remotes: add least-connections mirror strategy (round-robin remains default) (#122)

## Why

The mirrorlist (PR #121) always load-balances round-robin. Round-robin is oblivious to how busy each mirror is, so a slow or saturated mirror keeps getting its fair share of new requests. This adds an opt-in **least-connections** strategy that favors the mirror currently handling the fewest in-flight requests, steering new work toward idle mirrors. Round-robin stays the default, so existing remotes are unchanged.

## How

- **Model**: `models.Remote` gains `mirror_strategy` (`round_robin` default/empty, or `least_conn`). `ValidateMirrorStrategy` checks the enum and requires a non-empty mirrorlist for `least_conn`. Empty behaves as `round_robin` for back-compat.
- **DB**: additive `mirror_strategy TEXT NOT NULL DEFAULT 'round_robin'` column (CREATE TABLE + `ADD COLUMN IF NOT EXISTS`), wired through remoteCols/scanRemote/CreateRemote/UpdateRemote; empty normalized to `round_robin` on write.
- **Engine**: a per-remote, per-pool-URL atomic in-flight gauge is incremented around each upstream call (head/fetch/checkUpstream). For a `least_conn` remote the attempt order starts with the least-loaded pool URL (ties broken by the existing round-robin rotation). Round-robin path and failover order are unchanged; single-URL pools are a no-op.
- **Tests**: unit tests for least-loaded selection, round-robin default, gauge inc/dec, single-URL no-op, and validation; DB round-trip covers the new column; docker e2e adds a `least_conn` distribution test plus a real `dnf` install through a `least_conn` remote.

Back-compat: unset/empty `mirror_strategy` is `round_robin`, so all existing remotes keep their current behavior.
Reviewed-on: #122
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

.gitignore

@@ -1,2 +1,6 @@
 bin/
-terraform/
+/terraform/
+
+# e2e-docker fixtures are real package files (.rpm, .tgz, .whl, .zip, ...) that
+# are intentionally tracked, overriding any global ignore of those extensions.
+!e2e-docker/fixtures/**

.woodpecker/docker.yaml

@@ -8,6 +8,8 @@ steps:
     settings:
       registry: git.unkin.net
       repo: git.unkin.net/unkin/artifactapi
+      build_args:
+        VERSION: ${CI_COMMIT_TAG}
       username: droneci
       password:
         from_secret: DRONECI_PASSWORD
@@ -23,7 +25,7 @@ steps:
       dockerfile: ui/Dockerfile.ui
       context: ui
       build_args:
-        - BASE_PATH=/ui
+        BASE_PATH: /ui
       username: droneci
       password:
         from_secret: DRONECI_PASSWORD

Dockerfile

@@ -9,7 +9,8 @@ RUN go mod download
 
 COPY . .
 
-RUN CGO_ENABLED=0 go build -ldflags="-s -w" -o artifactapi ./cmd/artifactapi
+ARG VERSION=dev
+RUN CGO_ENABLED=0 go build -ldflags="-s -w -X main.version=${VERSION}" -o artifactapi ./cmd/artifactapi
 
 FROM gcr.io/distroless/static-debian12:nonroot
 

Makefile

@@ -1,4 +1,4 @@
-.PHONY: build test lint fmt e2e docker docker-ui compose clean tidy check-go
+.PHONY: build test lint fmt e2e docker-e2e docker docker-ui compose clean tidy check-go
 
 BINARY := bin/artifactapi
 MODULE := git.unkin.net/unkin/artifactapi
@@ -12,7 +12,7 @@ check-go:
 	fi
 
 build: check-go tidy
-	go build -ldflags="-s -w" -o $(BINARY) ./cmd/artifactapi
+	go build -ldflags="-s -w -X main.version=$(VERSION)" -o $(BINARY) ./cmd/artifactapi
 
 test: check-go
 	go test -race -count=1 ./pkg/... ./internal/...
@@ -28,6 +28,11 @@ fmt: check-go
 e2e: check-go
 	TESTCONTAINERS_RYUK_DISABLED=true go test -tags=e2e -race -count=1 -timeout=5m ./e2e/...
 
+# Build the container, bring up the full docker-compose stack + a mock upstream,
+# and run the black-box suite against the running product.
+docker-e2e: check-go
+	./scripts/docker-e2e.sh
+
 docker:
 	docker build -t artifactapi:$(VERSION) .
 

README.md

@@ -32,9 +32,150 @@ API: `http://localhost:8000` | Frontend: `http://localhost:5173`
 | `puppet` | `v3/modules/*`, `v3/releases*` | `.tar.gz` |
 | `terraform` | `*/versions` | `*/download/*/*` |
 | `goproxy` | `@v/list`, `@latest` | `.info`, `.mod`, `.zip` |
+| `github_rpm` | `repodata/*` (synthesized) | `.rpm` (redirected) |
 
 Providers classify paths automatically. Users only configure what to proxy and TTLs.
 
+### `github_rpm` — GitHub releases as a yum repo (metadata-only, no precache)
+
+A `github_rpm` remote turns a GitHub repo's **releases** into a real `dnf`/`yum`
+repository without ever caching the packages. It scans releases for `.rpm`
+assets, derives each package's metadata (NEVRA, requires/provides/conflicts/
+obsoletes, files, checksum) and **synthesizes `repodata/` on the fly**. Package
+metadata comes from a **ranged GET of just the RPM header** (the header sits at
+the front of the file, so the whole package is never downloaded); the sha256
+checksum comes from the GitHub asset `digest` when present, else a one-time
+lazy stream. Derived metadata is cached (keyed by asset) so repodata generation
+is served from primed DB rows, never a cold on-demand derive.
+
+Each package's `<location>` points back at the remote, which **302-redirects**
+the download to the `releases_remote` — an existing generic `github.com` remote
+that streams the actual bytes. `dnf` follows the redirect transparently.
+
+#### Background syncer
+
+A single process-wide **background syncer** keeps every `github_rpm` remote's
+derived metadata current off the client request path:
+
+- **Prime on create.** Creating a `github_rpm` remote enqueues a background prime
+  scan, so its metadata is derived right away without blocking the create call.
+  The first `dnf` request is served from cache. If a request arrives before the
+  prime lands, it returns a retryable `503` (with `Retry-After`) rather than
+  serving an empty repo or blocking on a multi-minute derive.
+- **Periodic re-check, driven by `mutable_ttl`.** Each remote is re-checked for
+  new or changed releases no more often than its `mutable_ttl`. New/changed
+  assets are derived incrementally; assets already cached are never re-fetched,
+  and assets that disappear upstream are pruned.
+- **ETag / 304 conditional requests.** The releases-list `ETag` is stored per
+  remote and sent as `If-None-Match`; a `304 Not Modified` means nothing changed
+  and the syncer derives nothing. GitHub does not count `304` conditional
+  responses against the rate limit, so an unchanged repo is nearly free — this is
+  the main lever keeping GitHub traffic low.
+- **Global rate limit.** Every GitHub call (releases list + each ranged asset
+  header GET) passes through a single token-bucket limiter **shared across all
+  remotes**, so GitHub is never hammered. Configure a token (`password`) on the
+  remote for the higher authenticated rate limit (~5000/hr vs ~60/hr
+  unauthenticated).
+- **Multi-replica coordination.** State is shared through the database. Before a
+  periodic scan a replica must atomically claim a per-remote lease
+  (`github_rpm_sync_state`: `last_synced_at`, `etag`, `sync_lease_owner`,
+  `sync_lease_expires`); only the winner scans. This bounds total GitHub load to
+  ~once per `mutable_ttl` regardless of replica count, and the shared `etag`
+  lets any replica issue the conditional request.
+
+```hcl
+# Backend that serves the actual .rpm bytes from github.com.
+resource "artifactapi_remote_generic" "github" {
+  name     = "github"
+  base_url = "https://github.com"
+  patterns = [
+    "acme/tools/releases/download/.*\\.rpm$", # allowlist the repo's release assets
+  ]
+}
+
+resource "artifactapi_remote_github_rpm" "acme-tools" {
+  name            = "acme-tools"
+  base_url        = "https://api.github.com/repos/acme/tools" # the releases API root
+  releases_remote = "github"                                  # backend for downloads
+  mutable_ttl     = 3600                                      # release re-scan interval
+
+  # Optional: restrict which release assets become packages (regex on filename).
+  patterns = [".*\\.x86_64\\.rpm$", ".*\\.noarch\\.rpm$"]
+
+  # Optional: a token for private repos / higher API rate limits.
+  # password = "ghp_..."
+}
+```
+
+`dnf` config: `baseurl=https://artifactapi.example/api/v1/remote/acme-tools`.
+The repo is multi-arch (no `$basearch` needed) — `dnf` selects matching packages
+from the synthesized metadata.
+
+### GitHub authentication
+
+Anonymous GitHub is capped at **60 requests/hour** and cannot read private
+repositories. Configure a **server-level GitHub credential** to raise the ceiling
+to roughly **5000 requests/hour** and to read private-repo release assets. The
+credential is a process-wide machine identity applied by default to *every*
+outbound GitHub request — the releases scan, the ranged asset-header fetches, and
+the generic-github byte proxy that streams private release assets.
+
+The credential is read from the environment (deliver it from a Vault or
+Kubernetes secret). It is **never** stored per-remote in the database, **never**
+returned by any API, and **never** logged. Configure **exactly one** mode.
+
+**Precedence.** A remote's own `username`/`password` credential still wins for
+that remote's requests; the server credential is the default for everything else.
+With no credential configured at all, requests stay anonymous (current behavior).
+Partial configuration (e.g. an App id with no private key) is a **startup error**
+— artifactapi fails closed rather than silently falling back to anonymous.
+
+Both modes share the syncer's single global rate limiter, so a token simply
+raises the effective GitHub ceiling; the default limiter settings stay safe.
+
+#### Mode 1 — Personal Access Token (minimum viable, recommended for free accounts)
+
+Set `GITHUB_TOKEN`. It is sent as `Authorization: Bearer <token>`.
+
+Recommended free-account setup — a **fine-grained PAT** scoped to just the target
+repositories:
+
+1. GitHub → *Settings → Developer settings → Personal access tokens →
+   Fine-grained tokens → Generate new token*.
+2. Limit *Repository access* to the specific repo(s) serving releases.
+3. Grant repository permissions **Contents: Read-only** and **Metadata:
+   Read-only** (Metadata is mandatory and auto-selected).
+
+A classic PAT with the `repo` scope also works but is broader than necessary.
+
+```bash
+GITHUB_TOKEN=github_pat_xxxxxxxx
+```
+
+#### Mode 2 — GitHub App installation token (proper machine identity)
+
+A GitHub App is not tied to a personal account and can be created and installed on
+free personal repos. artifactapi mints a short-lived RS256 **JWT** from the app
+private key, exchanges it at `POST /app/installations/{id}/access_tokens` for a
+~1-hour **installation access token**, caches that token, and refreshes it a few
+minutes before expiry (thread-safe, single-flighted).
+
+1. GitHub → *Settings → Developer settings → GitHub Apps → New GitHub App*.
+2. Under *Permissions → Repository permissions* grant **Contents: Read-only**
+   (Metadata: Read-only is implied).
+3. Generate a **private key** (downloads a PEM) and note the **App ID**.
+4. *Install* the App on the account and select the target repositories, then read
+   the **Installation ID** from the installation URL
+   (`.../settings/installations/<installation-id>`).
+
+```bash
+GITHUB_APP_ID=123456
+GITHUB_APP_INSTALLATION_ID=7654321
+GITHUB_APP_PRIVATE_KEY_PATH=/etc/artifactapi/github-app.pem
+# or inline PEM (e.g. mounted from a secret):
+# GITHUB_APP_PRIVATE_KEY="-----BEGIN RSA PRIVATE KEY-----\n...\n-----END RSA PRIVATE KEY-----"
+```
+
 ## Terraform
 
 Remotes and virtuals are managed by Terraform. Each package type has its own resource:
@@ -89,6 +230,54 @@ resource "artifactapi_virtual" "helm" {
 
 Provider: [terraform-provider-artifactapi](../terraform-provider-artifactapi)
 
+### Serving providers as a registry
+
+A local `terraform` repo is a real provider registry: upload
+`terraform-provider-{type}_{version}_{os}_{arch}.zip` files under
+`{namespace}/{type}/`, and Terraform installs them from a bare source address —
+no `.terraformrc` mirror config:
+
+```hcl
+terraform {
+  required_providers {
+    artifactapi = {
+      source  = "artifactapi.k8s.syd1.au.unkin.net/<repo>/<type>"
+      version = "0.1.2"
+    }
+  }
+}
+```
+
+The Terraform *namespace* segment is the artifactapi repo name; the provider is
+matched by *type*. The registry serves service discovery
+(`/.well-known/terraform.json`), the `providers.v1` version/download endpoints,
+and a GPG-signed `SHA256SUMS` per the provider registry protocol.
+
+Signing needs a GPG key. By default artifactapi generates one on first start and
+stores it in the database (`signing_keys` table), so every replica shares it and
+there's nothing to provision. To bring your own key instead, point
+`TF_SIGNING_KEY_PATH` at an armored private key (optionally
+`TF_SIGNING_KEY_PASSPHRASE`), which takes precedence over the generated one.
+`TF_PROVIDER_PROTOCOLS` (default `5.0,6.0`) sets the advertised plugin protocols.
+
+### Local docker registry
+
+A local `docker` repo is a real container registry, not a mirror: it serves the
+Docker Registry HTTP API V2 for both push and pull, so any client (`docker`,
+`podman`, `skopeo`, `buildah`) can use it directly.
+
+```sh
+docker tag myapp:latest artifactapi.k8s.syd1.au.unkin.net/docker-internal/myapp:latest
+docker push        artifactapi.k8s.syd1.au.unkin.net/docker-internal/myapp:latest
+docker pull        artifactapi.k8s.syd1.au.unkin.net/docker-internal/myapp:latest
+```
+
+The first path segment after `/v2/` is the artifactapi repo name; the remainder
+is the image name. Blobs and manifests are stored through the shared
+content-addressable store (deduplicated by digest, reaped by GC once
+unreferenced); tags are mutable references and re-pushing a tag moves it. Blob
+uploads support both the monolithic and chunked (`POST`/`PATCH`/`PUT`) flows.
+
 ## Access Control
 
 | Field | Default | Behaviour |
@@ -149,6 +338,15 @@ S3 client supports MinIO, Ceph RGW, and AWS S3 (via minio-go).
 | `MINIO_BUCKET` | `artifacts` | S3 bucket |
 | `MINIO_SECURE` | `false` | Use HTTPS for S3 |
 | `MINIO_REGION` | | S3 region (AWS) |
+| `GITHUB_SYNC_RATE` | `1` | `github_rpm` syncer global GitHub request rate (req/s), shared across all remotes. `1`/s = 3600/hr, under an authenticated token's ~5000/hr; unauthenticated (~60/hr) relies on ETag/304 |
+| `GITHUB_SYNC_BURST` | `5` | Token-bucket burst for the shared limiter |
+| `GITHUB_SYNC_WORKERS` | `3` | Concurrent `github_rpm` scan workers |
+| `GITHUB_SYNC_POLL_INTERVAL` | `60` | Base scheduler tick in seconds; per-remote cadence is its `mutable_ttl`, enforced by the DB lease |
+| `GITHUB_TOKEN` | | Server-level GitHub PAT (fine-grained or classic), sent as `Authorization: Bearer`. Applies to every GitHub request; per-remote creds override it. See [GitHub authentication](#github-authentication) |
+| `GITHUB_APP_ID` | | GitHub App id (App auth mode; mutually exclusive with `GITHUB_TOKEN`) |
+| `GITHUB_APP_INSTALLATION_ID` | | GitHub App installation id |
+| `GITHUB_APP_PRIVATE_KEY` | | GitHub App private key, inline PEM |
+| `GITHUB_APP_PRIVATE_KEY_PATH` | | GitHub App private key, file path (alternative to inline PEM) |
 
 ## Development
 

cmd/artifactapi/main.go

@@ -13,6 +13,8 @@ import (
 	"git.unkin.net/unkin/artifactapi/internal/tui"
 )
 
+var version = "dev"
+
 func main() {
 	if len(os.Args) > 1 && os.Args[1] == "tui" {
 		endpoint := os.Getenv("ARTIFACTAPI_ENDPOINT")
@@ -42,7 +44,7 @@ func main() {
 	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 	defer cancel()
 
-	srv, err := server.New(cfg)
+	srv, err := server.New(cfg, version)
 	if err != nil {
 		slog.Error("failed to create server", "error", err)
 		os.Exit(1)

docker-compose.e2e.yml

@@ -0,0 +1,34 @@
+# Overlay for the dockerised end-to-end suite (scripts/docker-e2e.sh).
+# Adds a static mock upstream that the artifactapi container proxies, so the
+# caching tests are hermetic and need no internet access.
+services:
+  mockupstream:
+    image: nginx:alpine
+    volumes:
+      - ./e2e-docker/fixtures:/usr/share/nginx/html:ro,z
+    # No host port needed: only the artifactapi container talks to it, and the
+    # tests compare served bytes against the on-disk fixtures.
+
+  # Two constant-body upstreams for the multi-base_url suite: each returns a
+  # distinct, upstream-identifying body for any path, so round-robin
+  # distribution across a two-mirror remote is directly observable.
+  mockupstreama:
+    image: nginx:alpine
+    volumes:
+      - ./e2e-docker/mirror-conf/a.conf:/etc/nginx/conf.d/default.conf:ro,z
+  mockupstreamb:
+    image: nginx:alpine
+    volumes:
+      - ./e2e-docker/mirror-conf/b.conf:/etc/nginx/conf.d/default.conf:ro,z
+
+  artifactapi:
+    # The host port is set via ARTIFACTAPI_PORT (see scripts/docker-e2e.sh),
+    # defaulting to 8000; the e2e run uses 8001 to avoid colliding with a
+    # locally-running instance.
+    depends_on:
+      mockupstream:
+        condition: service_started
+      mockupstreama:
+        condition: service_started
+      mockupstreamb:
+        condition: service_started

docker-compose.yml

@@ -2,7 +2,7 @@ services:
   artifactapi:
     build: .
     ports:
-      - "8000:8000"
+      - "${ARTIFACTAPI_PORT:-8000}:8000"
     environment:
       LISTEN_ADDR: ":8000"
       DBHOST: postgres

e2e-docker/README.md

@@ -0,0 +1,51 @@
+# Dockerised end-to-end suite
+
+Black-box tests that run against a fully **containerised** artifactapi stack
+(built image + Postgres + Redis + MinIO) plus a static mock upstream. Unlike the
+in-process `e2e/` suite (testcontainers, server run in-process), these only speak
+HTTP to the running product, so they exercise the shipped container image.
+
+## Run
+
+```bash
+make docker-e2e          # build image, compose up, run suite, compose down
+```
+
+`scripts/docker-e2e.sh` builds and starts `docker-compose.yml` +
+`docker-compose.e2e.yml`, waits for `/health`, then runs
+`go test -tags=dockere2e ./e2e-docker/...` and tears everything down.
+
+The stack publishes artifactapi on host port **8001** (to avoid colliding with a
+local instance on 8000). Override with `ARTIFACTAPI_URL` to point the tests at an
+already-running stack.
+
+## Coverage
+
+- **Repository lifecycle** — add / change / delete for remote, local and virtual repos.
+- **Caching** — one immutable artifact per remote package type (generic, docker,
+  helm, pypi, npm, rpm, alpine, puppet, terraform, goproxy) proxied through the
+  mock upstream: first fetch `X-Artifact-Source: remote`, second `cache`, bytes
+  verified against the origin fixture.
+- **Local uploads** — generic (upload/download), pypi (wheel + generated `simple/`
+  index), rpm (real package + **automatic repodata** generation).
+- **Virtual repositories** — pypi simple-index merge and helm `index.yaml` merge
+  across two members.
+- **Mirrorlist** — an rpm remote with a `mirrorlist` of extra upstream mirrors
+  (pool = `base_url` + `mirrorlist`): round-robin distribution across both mirrors
+  (constant-body `mockupstreama` / `mockupstreamb`), failover past a dead primary,
+  no-mirrorlist regression, and a real `dnf` (stock `rockylinux:9` container)
+  `makecache` + `install` through a two-mirror rpm remote whose `base_url` is dead
+  — a dead mirror must not break the client.
+- **Mirror strategy (`least_conn`)** — a `mirror_strategy: least_conn` rpm remote
+  over the two constant-body mirrors exercises the least-connections selection
+  path end-to-end (both mirrors serve, all requests succeed), plus a real `dnf`
+  install through a `least_conn` remote with a dead primary (failover unchanged).
+  The precise least-loaded pick is asserted deterministically in the proxy unit
+  test, since an in-flight-skew assertion over HTTP is timing-sensitive.
+
+## Fixtures
+
+`fixtures/` is served by the mock upstream at its web root. Paths mirror each
+provider's upstream URL layout (e.g. `v2/...` for docker, `v1/providers/...` for
+terraform). The RPM under `fixtures/rpmrepo/Packages/` is a real package so the
+rpm provider can parse its metadata for repodata generation.

e2e-docker/caching_test.go

@@ -0,0 +1,76 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"bytes"
+	"fmt"
+	"net/http"
+	"testing"
+)
+
+// TestCachingPerProvider proxies one immutable artifact for every remote
+// package type through the mock upstream and asserts: first fetch is served
+// from the remote, the second from cache, and the bytes match the origin.
+func TestCachingPerProvider(t *testing.T) {
+	cases := []struct {
+		pkgType string
+		// path is the request path under /api/v1/remote/<name>/. The provider
+		// derives the upstream URL from it (docker prepends /v2/, terraform
+		// prepends /v1/providers/), and the fixture lives at that resolved path.
+		path    string
+		fixture string
+	}{
+		{"generic", "blobs/hello.bin", "blobs/hello.bin"},
+		{"npm", "mypkg/-/mypkg-1.0.0.tgz", "mypkg/-/mypkg-1.0.0.tgz"},
+		{"helm", "charts/mychart-1.0.0.tgz", "charts/mychart-1.0.0.tgz"},
+		{"pypi", "packages/foo-1.0-py3-none-any.whl", "packages/foo-1.0-py3-none-any.whl"},
+		{"rpm", "rpmrepo/Packages/e2e-testpkg-1.0-1.noarch.rpm", "rpmrepo/Packages/e2e-testpkg-1.0-1.noarch.rpm"},
+		{"alpine", "alpine/x86_64/testpkg-1.0-r0.apk", "alpine/x86_64/testpkg-1.0-r0.apk"},
+		{"puppet", "puppet-releases/author-mod-1.0.0.tar.gz", "puppet-releases/author-mod-1.0.0.tar.gz"},
+		{"goproxy", "goproxy/example.com/mod/@v/v1.0.0.zip", "goproxy/example.com/mod/@v/v1.0.0.zip"},
+		{"terraform", "hashicorp/aws/download/pkg.zip", "v1/providers/hashicorp/aws/download/pkg.zip"},
+		{"docker", "library/testimg/blobs/blobdata", "v2/library/testimg/blobs/blobdata"},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.pkgType, func(t *testing.T) {
+			name := "cache-" + tc.pkgType
+			createRepo(t, fmt.Sprintf(`{
+				"name": %q,
+				"package_type": %q,
+				"repo_type": "remote",
+				"base_url": %q,
+				"stale_on_error": true
+			}`, name, tc.pkgType, mockUpstream()))
+			defer deleteRepo(t, name)
+
+			want := fixtureBytes(t, tc.fixture)
+			url := api("/api/v1/remote/" + name + "/" + tc.path)
+
+			// First fetch: from remote.
+			resp, body := doRequest(t, http.MethodGet, url, nil, "")
+			if resp.StatusCode != http.StatusOK {
+				t.Fatalf("first fetch: status %d: %s", resp.StatusCode, body)
+			}
+			if src := resp.Header.Get("X-Artifact-Source"); src != "remote" {
+				t.Fatalf("first fetch source = %q, want remote", src)
+			}
+			if !bytes.Equal(body, want) {
+				t.Fatalf("first fetch body mismatch: got %d bytes, want %d", len(body), len(want))
+			}
+
+			// Second fetch: from cache, identical bytes.
+			resp, body = doRequest(t, http.MethodGet, url, nil, "")
+			if resp.StatusCode != http.StatusOK {
+				t.Fatalf("second fetch: status %d: %s", resp.StatusCode, body)
+			}
+			if src := resp.Header.Get("X-Artifact-Source"); src != "cache" {
+				t.Fatalf("second fetch source = %q, want cache", src)
+			}
+			if !bytes.Equal(body, want) {
+				t.Fatalf("cached body mismatch: got %d bytes, want %d", len(body), len(want))
+			}
+		})
+	}
+}

e2e-docker/docker_local_test.go

@@ -0,0 +1,177 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"net/http"
+	"strings"
+	"testing"
+)
+
+func digestOf(b []byte) string {
+	sum := sha256.Sum256(b)
+	return "sha256:" + hex.EncodeToString(sum[:])
+}
+
+// pushBlobMonolithic uploads a blob with POST (open session) then PUT?digest
+// (whole body) — the monolithic-after-POST flow.
+func pushBlobMonolithic(t *testing.T, repo, image string, blob []byte) {
+	t.Helper()
+	dgst := digestOf(blob)
+
+	resp, body := doRequest(t, http.MethodPost, api("/v2/"+repo+"/"+image+"/blobs/uploads/"), nil, "")
+	if resp.StatusCode != http.StatusAccepted {
+		t.Fatalf("start upload: status %d: %s", resp.StatusCode, body)
+	}
+	loc := resp.Header.Get("Location")
+	if loc == "" {
+		t.Fatalf("start upload: no Location header")
+	}
+
+	resp, body = doRequest(t, http.MethodPut, baseURL()+loc+"?digest="+dgst, blob, "application/octet-stream")
+	if resp.StatusCode != http.StatusCreated {
+		t.Fatalf("finish upload: status %d: %s", resp.StatusCode, body)
+	}
+	if got := resp.Header.Get("Docker-Content-Digest"); got != dgst {
+		t.Fatalf("finish upload: digest mismatch: got %q want %q", got, dgst)
+	}
+}
+
+// pushBlobChunked uploads a blob with POST then PATCH (body) then PUT?digest
+// (empty) — the chunked flow a real docker daemon uses.
+func pushBlobChunked(t *testing.T, repo, image string, blob []byte) {
+	t.Helper()
+	dgst := digestOf(blob)
+
+	resp, body := doRequest(t, http.MethodPost, api("/v2/"+repo+"/"+image+"/blobs/uploads/"), nil, "")
+	if resp.StatusCode != http.StatusAccepted {
+		t.Fatalf("start upload: status %d: %s", resp.StatusCode, body)
+	}
+	loc := resp.Header.Get("Location")
+
+	resp, body = doRequest(t, http.MethodPatch, baseURL()+loc, blob, "application/octet-stream")
+	if resp.StatusCode != http.StatusAccepted {
+		t.Fatalf("patch upload: status %d: %s", resp.StatusCode, body)
+	}
+	if got := resp.Header.Get("Range"); got != fmt.Sprintf("0-%d", len(blob)-1) {
+		t.Fatalf("patch upload: unexpected Range %q", got)
+	}
+	loc = resp.Header.Get("Location")
+
+	resp, body = doRequest(t, http.MethodPut, baseURL()+loc+"?digest="+dgst, nil, "")
+	if resp.StatusCode != http.StatusCreated {
+		t.Fatalf("finish upload: status %d: %s", resp.StatusCode, body)
+	}
+}
+
+// TestLocalDockerPushPull exercises a full container push and pull against a
+// local docker repo using the Docker Registry HTTP API V2, the way a docker
+// client would: upload the config and layer blobs, push the manifest under a
+// tag, then pull the manifest and blobs back byte-identically.
+func TestLocalDockerPushPull(t *testing.T) {
+	createRepo(t, `{"name":"docker-internal","package_type":"docker","repo_type":"local"}`)
+	defer deleteRepo(t, "docker-internal")
+
+	const image = "team/app"
+	const tag = "v1.0.0"
+
+	// /v2/ version check.
+	resp, _ := doRequest(t, http.MethodGet, api("/v2/"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("/v2/ ping: status %d", resp.StatusCode)
+	}
+
+	config := []byte(`{"architecture":"amd64","os":"linux","config":{},"rootfs":{"type":"layers","diff_ids":["sha256:0000000000000000000000000000000000000000000000000000000000000000"]}}`)
+	layer := bytes.Repeat([]byte("artifactapi-layer-data-"), 4096) // ~90 KB opaque layer
+
+	configDigest := digestOf(config)
+	layerDigest := digestOf(layer)
+
+	// A brand-new blob should be absent (this is the client's mount check).
+	resp, _ = doRequest(t, http.MethodHead, api("/v2/"+"docker-internal/"+image+"/blobs/"+configDigest), nil, "")
+	if resp.StatusCode != http.StatusNotFound {
+		t.Fatalf("pre-push blob HEAD: expected 404, got %d", resp.StatusCode)
+	}
+
+	pushBlobMonolithic(t, "docker-internal", image, config)
+	pushBlobChunked(t, "docker-internal", image, layer)
+
+	manifest := []byte(fmt.Sprintf(`{"schemaVersion":2,"mediaType":"application/vnd.docker.distribution.manifest.v2+json","config":{"mediaType":"application/vnd.docker.container.image.v1+json","size":%d,"digest":%q},"layers":[{"mediaType":"application/vnd.docker.image.rootfs.diff.tar.gzip","size":%d,"digest":%q}]}`,
+		len(config), configDigest, len(layer), layerDigest))
+	manifestDigest := digestOf(manifest)
+	manifestType := "application/vnd.docker.distribution.manifest.v2+json"
+
+	resp, body := doRequest(t, http.MethodPut, api("/v2/docker-internal/"+image+"/manifests/"+tag), manifest, manifestType)
+	if resp.StatusCode != http.StatusCreated {
+		t.Fatalf("push manifest: status %d: %s", resp.StatusCode, body)
+	}
+	if got := resp.Header.Get("Docker-Content-Digest"); got != manifestDigest {
+		t.Fatalf("push manifest: digest %q want %q", got, manifestDigest)
+	}
+
+	// --- pull back ---
+
+	// Manifest by tag.
+	resp, body = doRequest(t, http.MethodGet, api("/v2/docker-internal/"+image+"/manifests/"+tag), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("pull manifest by tag: status %d: %s", resp.StatusCode, body)
+	}
+	if !bytes.Equal(body, manifest) {
+		t.Fatalf("pulled manifest bytes differ from pushed")
+	}
+	if ct := resp.Header.Get("Content-Type"); ct != manifestType {
+		t.Fatalf("pulled manifest content-type %q want %q", ct, manifestType)
+	}
+	if got := resp.Header.Get("Docker-Content-Digest"); got != manifestDigest {
+		t.Fatalf("pulled manifest digest %q want %q", got, manifestDigest)
+	}
+
+	// Manifest by digest.
+	resp, body = doRequest(t, http.MethodGet, api("/v2/docker-internal/"+image+"/manifests/"+manifestDigest), nil, "")
+	if resp.StatusCode != http.StatusOK || !bytes.Equal(body, manifest) {
+		t.Fatalf("pull manifest by digest: status %d, equal=%v", resp.StatusCode, bytes.Equal(body, manifest))
+	}
+
+	// Blobs by digest.
+	for _, tc := range []struct {
+		name   string
+		digest string
+		want   []byte
+	}{
+		{"config", configDigest, config},
+		{"layer", layerDigest, layer},
+	} {
+		resp, body = doRequest(t, http.MethodGet, api("/v2/docker-internal/"+image+"/blobs/"+tc.digest), nil, "")
+		if resp.StatusCode != http.StatusOK {
+			t.Fatalf("pull %s blob: status %d", tc.name, resp.StatusCode)
+		}
+		if !bytes.Equal(body, tc.want) {
+			t.Fatalf("pulled %s blob bytes differ", tc.name)
+		}
+		if got := resp.Header.Get("Docker-Content-Digest"); got != tc.digest {
+			t.Fatalf("pulled %s blob digest %q want %q", tc.name, got, tc.digest)
+		}
+	}
+
+	// tags/list reflects the pushed tag.
+	resp, body = doRequest(t, http.MethodGet, api("/v2/docker-internal/"+image+"/tags/list"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("tags/list: status %d: %s", resp.StatusCode, body)
+	}
+	if !strings.Contains(string(body), `"`+tag+`"`) {
+		t.Fatalf("tags/list missing tag %q: %s", tag, body)
+	}
+	if !strings.Contains(string(body), `"docker-internal/`+image+`"`) {
+		t.Fatalf("tags/list wrong repository name: %s", body)
+	}
+
+	// A now-present blob HEAD should succeed (client would skip re-upload).
+	resp, _ = doRequest(t, http.MethodHead, api("/v2/docker-internal/"+image+"/blobs/"+layerDigest), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("post-push blob HEAD: expected 200, got %d", resp.StatusCode)
+	}
+}

e2e-docker/fixtures/blobs/hello.bin

@@ -0,0 +1 @@
+hello artifactapi generic blob

e2e-docker/fixtures/helm-a/index.yaml

@@ -0,0 +1,8 @@
+apiVersion: v1
+entries:
+  alpha:
+    - name: alpha
+      version: 1.0.0
+      urls:
+        - charts/alpha-1.0.0.tgz
+generated: "2026-01-01T00:00:00Z"

e2e-docker/fixtures/helm-b/index.yaml

@@ -0,0 +1,8 @@
+apiVersion: v1
+entries:
+  beta:
+    - name: beta
+      version: 2.0.0
+      urls:
+        - charts/beta-2.0.0.tgz
+generated: "2026-01-01T00:00:00Z"

e2e-docker/fixtures/rpm-mirror/repodata/repomd.xml

@@ -0,0 +1,55 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<repomd xmlns="http://linux.duke.edu/metadata/repo" xmlns:rpm="http://linux.duke.edu/metadata/rpm">
+  <revision>1786573032</revision>
+  <data type="primary">
+    <checksum type="sha256">d82f717e4da1afe96b8e7857de9e852f5785c0d75734e50d0f8afdcbc6261b08</checksum>
+    <open-checksum type="sha256">3345bb631380ae6c0620fe2a29cf7dff2ed4e28c5cb06c91e8a1628ba1979bcb</open-checksum>
+    <location href="repodata/d82f717e4da1afe96b8e7857de9e852f5785c0d75734e50d0f8afdcbc6261b08-primary.xml.gz"/>
+    <timestamp>1786573032</timestamp>
+    <size>631</size>
+    <open-size>1192</open-size>
+  </data>
+  <data type="filelists">
+    <checksum type="sha256">daa313cc5eeb7df556e1d4885d7701b10b9f012f436ef239fa46827f966222be</checksum>
+    <open-checksum type="sha256">648bd0ce00fda09abbc6e9c3ff3278518a76f258576ac24cd10c12e41e0e5bd7</open-checksum>
+    <location href="repodata/daa313cc5eeb7df556e1d4885d7701b10b9f012f436ef239fa46827f966222be-filelists.xml.gz"/>
+    <timestamp>1786573032</timestamp>
+    <size>256</size>
+    <open-size>338</open-size>
+  </data>
+  <data type="other">
+    <checksum type="sha256">8510c74a6f288828bbc92abee5d0d8ae9687d3c31a2579ea95e31a4c3a320d85</checksum>
+    <open-checksum type="sha256">c42cfd3843e9c53a60ad84bded44aa46c65faae7b3da99a099a9ca0b018872a9</open-checksum>
+    <location href="repodata/8510c74a6f288828bbc92abee5d0d8ae9687d3c31a2579ea95e31a4c3a320d85-other.xml.gz"/>
+    <timestamp>1786573032</timestamp>
+    <size>296</size>
+    <open-size>399</open-size>
+  </data>
+  <data type="primary_db">
+    <checksum type="sha256">f6bd7755da13d9726381048f467992869104a4c5521338ef740dc35eb85b9b71</checksum>
+    <open-checksum type="sha256">c45c85d12ccb0f8172b7bfae466362c08ac1867559574a9fb9cb2118c04daddb</open-checksum>
+    <location href="repodata/f6bd7755da13d9726381048f467992869104a4c5521338ef740dc35eb85b9b71-primary.sqlite.bz2"/>
+    <timestamp>1786573032</timestamp>
+    <size>1740</size>
+    <open-size>106496</open-size>
+    <database_version>10</database_version>
+  </data>
+  <data type="filelists_db">
+    <checksum type="sha256">be3c6e4c7a13ece48bd5d6a4d6d5e6a2395fe006ef9c5f217f5b87144f465e57</checksum>
+    <open-checksum type="sha256">1ccfa3dff532d782ce3225aae807506a4ce4534291386f1c47455dcc6b70cfd6</open-checksum>
+    <location href="repodata/be3c6e4c7a13ece48bd5d6a4d6d5e6a2395fe006ef9c5f217f5b87144f465e57-filelists.sqlite.bz2"/>
+    <timestamp>1786573032</timestamp>
+    <size>764</size>
+    <open-size>28672</open-size>
+    <database_version>10</database_version>
+  </data>
+  <data type="other_db">
+    <checksum type="sha256">ba593cd8ab5ec1e127888707c1fd882920996f1ce173fd7a589d647918fd7da4</checksum>
+    <open-checksum type="sha256">5d4d38380f0e359bfc0a50033d4faa84c75c5ae8fe2ef11c1c82d64748e9b8e2</open-checksum>
+    <location href="repodata/ba593cd8ab5ec1e127888707c1fd882920996f1ce173fd7a589d647918fd7da4-other.sqlite.bz2"/>
+    <timestamp>1786573032</timestamp>
+    <size>738</size>
+    <open-size>24576</open-size>
+    <database_version>10</database_version>
+  </data>
+</repomd>

e2e-docker/helpers_test.go

@@ -0,0 +1,108 @@
+//go:build dockere2e
+
+// Package e2edocker holds the black-box end-to-end suite that runs against a
+// fully dockerised artifactapi stack (see scripts/docker-e2e.sh). Unlike the
+// in-process e2e suite, these tests only speak HTTP to the running container.
+package e2edocker
+
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+func baseURL() string {
+	if v := os.Getenv("ARTIFACTAPI_URL"); v != "" {
+		return strings.TrimRight(v, "/")
+	}
+	return "http://localhost:8000"
+}
+
+// mockUpstream is the base URL the artifactapi *container* uses to reach the
+// static mock upstream. It is resolved on the compose network, not the host.
+func mockUpstream() string {
+	if v := os.Getenv("MOCK_UPSTREAM_INTERNAL"); v != "" {
+		return strings.TrimRight(v, "/")
+	}
+	return "http://mockupstream"
+}
+
+func api(path string) string { return baseURL() + path }
+
+func fixtureBytes(t *testing.T, rel string) []byte {
+	t.Helper()
+	b, err := os.ReadFile(filepath.Join("fixtures", rel))
+	if err != nil {
+		t.Fatalf("read fixture %s: %v", rel, err)
+	}
+	return b
+}
+
+func doRequest(t *testing.T, method, url string, body []byte, contentType string) (*http.Response, []byte) {
+	t.Helper()
+	var r io.Reader
+	if body != nil {
+		r = bytes.NewReader(body)
+	}
+	req, err := http.NewRequest(method, url, r)
+	if err != nil {
+		t.Fatalf("%s %s: %v", method, url, err)
+	}
+	if contentType != "" {
+		req.Header.Set("Content-Type", contentType)
+	}
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatalf("%s %s: %v", method, url, err)
+	}
+	defer resp.Body.Close()
+	respBody, _ := io.ReadAll(resp.Body)
+	return resp, respBody
+}
+
+func createRepo(t *testing.T, jsonBody string) {
+	t.Helper()
+	resp, body := doRequest(t, http.MethodPost, api("/api/v2/remotes"), []byte(jsonBody), "application/json")
+	if resp.StatusCode != http.StatusCreated {
+		t.Fatalf("create repo: status %d: %s", resp.StatusCode, body)
+	}
+}
+
+func deleteRepo(t *testing.T, name string) {
+	t.Helper()
+	doRequest(t, http.MethodDelete, api("/api/v2/remotes/"+name), nil, "")
+}
+
+func createVirtual(t *testing.T, jsonBody string) {
+	t.Helper()
+	resp, body := doRequest(t, http.MethodPost, api("/api/v2/virtuals"), []byte(jsonBody), "application/json")
+	if resp.StatusCode != http.StatusCreated {
+		t.Fatalf("create virtual: status %d: %s", resp.StatusCode, body)
+	}
+}
+
+func deleteVirtual(t *testing.T, name string) {
+	t.Helper()
+	doRequest(t, http.MethodDelete, api("/api/v2/virtuals/"+name), nil, "")
+}
+
+// getEventually retries a GET until it returns 200 or the deadline passes. Used
+// for asynchronously-generated artifacts (e.g. rpm repodata after upload).
+func getEventually(t *testing.T, url string, timeout time.Duration) (*http.Response, []byte) {
+	t.Helper()
+	deadline := time.Now().Add(timeout)
+	var resp *http.Response
+	var body []byte
+	for {
+		resp, body = doRequest(t, http.MethodGet, url, nil, "")
+		if resp.StatusCode == http.StatusOK || time.Now().After(deadline) {
+			return resp, body
+		}
+		time.Sleep(250 * time.Millisecond)
+	}
+}

e2e-docker/leastconn_test.go

@@ -0,0 +1,105 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+)
+
+// TestLeastConnMultiBaseURL configures an rpm remote with mirror_strategy =
+// least_conn over a two-mirror pool and drives distinct cache-miss paths through
+// it, asserting every request succeeds and both mirrors serve traffic. This
+// exercises the least-connections selection path (leastConnOrder + the in-flight
+// gauge inc/dec around each upstream call) end-to-end through a real HTTP client.
+// A precise least-loaded assertion is timing-sensitive over HTTP and is covered
+// deterministically by the proxy unit test (TestLeastConnPicksLeastLoaded);
+// here, with requests issued serially, in-flight counts return to zero between
+// them so equal-load mirrors are spread by the round-robin tie-break.
+func TestLeastConnMultiBaseURL(t *testing.T) {
+	name := "e2e-leastconn"
+	createRepo(t, fmt.Sprintf(`{
+		"name": %q,
+		"package_type": "rpm",
+		"repo_type": "remote",
+		"base_url": %q,
+		"mirrorlist": [%q],
+		"mirror_strategy": "least_conn",
+		"stale_on_error": false
+	}`, name, mockUpstreamA(), mockUpstreamB()))
+	defer deleteRepo(t, name)
+
+	seenA, seenB := false, false
+	const n = 12
+	for i := 0; i < n; i++ {
+		url := api(fmt.Sprintf("/api/v1/remote/%s/lc/%d", name, i))
+		resp, body := doRequest(t, http.MethodGet, url, nil, "")
+		if resp.StatusCode != http.StatusOK {
+			t.Fatalf("request %d: status %d: %s", i, resp.StatusCode, body)
+		}
+		switch strings.TrimSpace(string(body)) {
+		case "UPSTREAM-A":
+			seenA = true
+		case "UPSTREAM-B":
+			seenB = true
+		default:
+			t.Fatalf("request %d: unexpected body %q", i, body)
+		}
+	}
+	if !seenA || !seenB {
+		t.Fatalf("least_conn remote did not reach both upstreams: A=%v B=%v", seenA, seenB)
+	}
+}
+
+// TestLeastConnDnfInstall drives a real dnf (stock rockylinux container) at a
+// two-mirror rpm remote configured with mirror_strategy = least_conn whose
+// primary base_url is dead: makecache + install must succeed via the live mirror.
+// This proves a real package-manager client installs correctly through a
+// least_conn remote and that failover semantics are unchanged under the new
+// strategy. Requires the compose network exported by scripts/docker-e2e.sh.
+func TestLeastConnDnfInstall(t *testing.T) {
+	network := os.Getenv("COMPOSE_NETWORK")
+	internal := os.Getenv("ARTIFACTAPI_INTERNAL")
+	if network == "" || internal == "" {
+		t.Skip("COMPOSE_NETWORK/ARTIFACTAPI_INTERNAL not set; run via scripts/docker-e2e.sh")
+	}
+	if _, err := exec.LookPath("docker"); err != nil {
+		t.Skip("docker not available on the test host")
+	}
+
+	name := "e2e-leastconn-dnf"
+	createRepo(t, fmt.Sprintf(`{
+		"name": %q,
+		"package_type": "rpm",
+		"repo_type": "remote",
+		"base_url": "http://mockupstream-dead:80",
+		"mirrorlist": [%q],
+		"mirror_strategy": "least_conn",
+		"stale_on_error": false
+	}`, name, mockUpstream()))
+	defer deleteRepo(t, name)
+
+	repoURL := strings.TrimRight(internal, "/") + "/api/v1/remote/" + name + "/rpm-mirror"
+	repoConf := fmt.Sprintf("[dnflc]\nname=dnflc\nbaseurl=%s\nenabled=1\ngpgcheck=0\nsslverify=0\nmetadata_expire=0\n", repoURL)
+	script := "set -euo pipefail; " +
+		"printf '%s' \"$REPO\" > /etc/yum.repos.d/dnflc.repo; " +
+		"dnf -y --disablerepo='*' --enablerepo=dnflc makecache; " +
+		"dnf -y --disablerepo='*' --enablerepo=dnflc install e2e-testpkg; " +
+		"rpm -q e2e-testpkg"
+
+	cmd := exec.Command("docker", "run", "--rm",
+		"--network", network,
+		"-e", "REPO="+repoConf,
+		"rockylinux:9", "bash", "-c", script)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("real dnf install through a least_conn remote failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(string(out), "e2e-testpkg-1.0-1") {
+		t.Fatalf("dnf did not install the expected package via least_conn remote; output:\n%s", out)
+	}
+}

e2e-docker/local_test.go

@@ -0,0 +1,193 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+)
+
+func uploadFile(t *testing.T, repo, filePath string, body []byte, contentType string) {
+	t.Helper()
+	url := api("/api/v2/remotes/" + repo + "/files/" + filePath)
+	resp, respBody := doRequest(t, http.MethodPut, url, body, contentType)
+	if resp.StatusCode != http.StatusCreated {
+		t.Fatalf("upload %s: status %d: %s", filePath, resp.StatusCode, respBody)
+	}
+}
+
+// TestLocalGenericUpload uploads a generic file and downloads it back.
+func TestLocalGenericUpload(t *testing.T) {
+	createRepo(t, `{"name":"local-generic","package_type":"generic","repo_type":"local"}`)
+	defer deleteRepo(t, "local-generic")
+
+	content := []byte("artifactapi local generic upload payload")
+	uploadFile(t, "local-generic", "data/hello.bin", content, "application/octet-stream")
+
+	resp, body := doRequest(t, http.MethodGet, api("/api/v1/local/local-generic/data/hello.bin"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("download: status %d: %s", resp.StatusCode, body)
+	}
+	if !bytes.Equal(body, content) {
+		t.Fatalf("downloaded content mismatch")
+	}
+}
+
+// TestLocalPyPIUpload uploads a wheel and validates the generated simple index.
+func TestLocalPyPIUpload(t *testing.T) {
+	createRepo(t, `{"name":"local-pypi","package_type":"pypi","repo_type":"local"}`)
+	defer deleteRepo(t, "local-pypi")
+
+	wheel := fixtureBytes(t, "packages/foo-1.0-py3-none-any.whl")
+	uploadFile(t, "local-pypi", "foo-1.0-py3-none-any.whl", wheel, "application/zip")
+
+	// Root index lists the package.
+	resp, body := doRequest(t, http.MethodGet, api("/api/v1/local/local-pypi/simple/"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("simple index: status %d: %s", resp.StatusCode, body)
+	}
+	if !strings.Contains(string(body), "foo") {
+		t.Fatalf("simple index missing package 'foo': %s", body)
+	}
+
+	// Per-package index lists the wheel file.
+	resp, body = doRequest(t, http.MethodGet, api("/api/v1/local/local-pypi/simple/foo/"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("package index: status %d: %s", resp.StatusCode, body)
+	}
+	if !strings.Contains(string(body), "foo-1.0-py3-none-any.whl") {
+		t.Fatalf("package index missing wheel: %s", body)
+	}
+
+	// The wheel downloads back byte-identical.
+	resp, body = doRequest(t, http.MethodGet, api("/api/v1/local/local-pypi/foo/foo-1.0-py3-none-any.whl"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("download wheel: status %d: %s", resp.StatusCode, body)
+	}
+	if !bytes.Equal(body, wheel) {
+		t.Fatalf("wheel content mismatch")
+	}
+}
+
+// TestLocalRPMRepodata uploads a real RPM and validates that repodata is
+// generated automatically (the special rpm-local feature).
+func TestLocalRPMRepodata(t *testing.T) {
+	createRepo(t, `{"name":"local-rpm","package_type":"rpm","repo_type":"local"}`)
+	defer deleteRepo(t, "local-rpm")
+
+	rpm := fixtureBytes(t, "rpmrepo/Packages/e2e-testpkg-1.0-1.noarch.rpm")
+	uploadFile(t, "local-rpm", "e2e-testpkg-1.0-1.noarch.rpm", rpm, "application/x-rpm")
+
+	// repodata is generated asynchronously after upload; poll for it.
+	resp, body := getEventually(t, api("/api/v1/local/local-rpm/repodata/repomd.xml"), 15*time.Second)
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("repomd.xml: status %d: %s", resp.StatusCode, body)
+	}
+	s := string(body)
+	if !strings.Contains(s, "<repomd") || !strings.Contains(s, "primary") {
+		t.Fatalf("repomd.xml not a valid repodata document: %s", s)
+	}
+}
+
+// TestLocalDebRepo uploads a .deb and validates that the flat apt index
+// (Packages / Release) is generated automatically from the parsed control
+// stanza (the deb-local analog of rpm repodata generation).
+func TestLocalDebRepo(t *testing.T) {
+	createRepo(t, `{"name":"local-deb","package_type":"deb","repo_type":"local"}`)
+	defer deleteRepo(t, "local-deb")
+
+	deb := testsupport.MinimalDeb("e2e-testpkg", "1.0.0", "amd64")
+	uploadFile(t, "local-deb", "e2e-testpkg_1.0.0_amd64.deb", deb, "application/vnd.debian.binary-package")
+
+	// The index is generated asynchronously after upload; poll for it.
+	resp, body := getEventually(t, api("/api/v1/local/local-deb/Packages"), 15*time.Second)
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("Packages: status %d: %s", resp.StatusCode, body)
+	}
+	pkgs := string(body)
+	for _, want := range []string{"Package: e2e-testpkg", "Version: 1.0.0", "Architecture: amd64", "Filename: pool/e2e-testpkg_1.0.0_amd64.deb", "SHA256:"} {
+		if !strings.Contains(pkgs, want) {
+			t.Fatalf("Packages missing %q:\n%s", want, pkgs)
+		}
+	}
+
+	resp, body = doRequest(t, http.MethodGet, api("/api/v1/local/local-deb/Release"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("Release: status %d: %s", resp.StatusCode, body)
+	}
+	rel := string(body)
+	for _, want := range []string{"Architectures: amd64", "SHA256:", "Packages"} {
+		if !strings.Contains(rel, want) {
+			t.Fatalf("Release missing %q:\n%s", want, rel)
+		}
+	}
+
+	// The .deb downloads back byte-identical from its pool path.
+	resp, body = doRequest(t, http.MethodGet, api("/api/v1/local/local-deb/pool/e2e-testpkg_1.0.0_amd64.deb"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("download deb: status %d: %s", resp.StatusCode, body)
+	}
+	if !bytes.Equal(body, deb) {
+		t.Fatalf("deb content mismatch")
+	}
+}
+
+// TestLocalAlpineIndex uploads an .apk to an alpine local repo and validates
+// that a per-arch APKINDEX.tar.gz is generated automatically from the parsed
+// .PKGINFO (the apk-local analog of rpm repodata / deb Packages generation).
+func TestLocalAlpineIndex(t *testing.T) {
+	createRepo(t, `{"name":"local-alpine","package_type":"alpine","repo_type":"local"}`)
+	defer deleteRepo(t, "local-alpine")
+
+	apk := testsupport.MinimalApk("e2e-testpkg", "1.0-r0", "x86_64")
+	uploadFile(t, "local-alpine", "x86_64/e2e-testpkg-1.0-r0.apk", apk, "application/vnd.android.package-archive")
+
+	// The index is generated asynchronously after upload; poll for it.
+	resp, body := getEventually(t, api("/api/v1/local/local-alpine/x86_64/APKINDEX.tar.gz"), 15*time.Second)
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("APKINDEX: status %d: %s", resp.StatusCode, body)
+	}
+
+	zr, err := gzip.NewReader(bytes.NewReader(body))
+	if err != nil {
+		t.Fatalf("APKINDEX not gzip: %v", err)
+	}
+	tarBytes, _ := io.ReadAll(zr)
+	tr := tar.NewReader(bytes.NewReader(tarBytes))
+	var index string
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatalf("APKINDEX not tar: %v", err)
+		}
+		if hdr.Name == "APKINDEX" {
+			b, _ := io.ReadAll(tr)
+			index = string(b)
+		}
+	}
+	for _, want := range []string{"P:e2e-testpkg", "V:1.0-r0", "A:x86_64", "C:Q1", "S:", "I:"} {
+		if !strings.Contains(index, want) {
+			t.Fatalf("APKINDEX missing %q:\n%s", want, index)
+		}
+	}
+
+	// The .apk downloads back byte-identical from its arch path.
+	resp, body = doRequest(t, http.MethodGet, api("/api/v1/local/local-alpine/x86_64/e2e-testpkg-1.0-r0.apk"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("download apk: status %d: %s", resp.StatusCode, body)
+	}
+	if !bytes.Equal(body, apk) {
+		t.Fatalf("apk content mismatch")
+	}
+}

e2e-docker/mirror-conf/a.conf

@@ -0,0 +1,9 @@
+# Mock upstream A for the multi-base_url e2e: any path returns a constant,
+# upstream-identifying body so round-robin distribution is observable.
+server {
+    listen 80;
+    location / {
+        default_type text/plain;
+        return 200 "UPSTREAM-A";
+    }
+}

e2e-docker/mirror-conf/b.conf

@@ -0,0 +1,8 @@
+# Mock upstream B for the multi-base_url e2e (see a.conf).
+server {
+    listen 80;
+    location / {
+        default_type text/plain;
+        return 200 "UPSTREAM-B";
+    }
+}

e2e-docker/multibaseurl_test.go

@@ -0,0 +1,163 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+)
+
+// mockUpstreamA/B are the constant-body upstreams (see docker-compose.e2e.yml)
+// that let the round-robin test observe which mirror served each request.
+func mockUpstreamA() string {
+	if v := os.Getenv("MOCK_UPSTREAM_A_INTERNAL"); v != "" {
+		return strings.TrimRight(v, "/")
+	}
+	return "http://mockupstreama"
+}
+
+func mockUpstreamB() string {
+	if v := os.Getenv("MOCK_UPSTREAM_B_INTERNAL"); v != "" {
+		return strings.TrimRight(v, "/")
+	}
+	return "http://mockupstreamb"
+}
+
+// TestMultiBaseURLRoundRobin configures an rpm remote with base_url = mirror A
+// and mirrorlist = [mirror B] and drives distinct paths through it, asserting
+// both mirrors serve traffic. Each path is a cache miss, so every request reaches
+// upstream and the round-robin cursor alternates mirrors.
+func TestMultiBaseURLRoundRobin(t *testing.T) {
+	name := "e2e-rr"
+	createRepo(t, fmt.Sprintf(`{
+		"name": %q,
+		"package_type": "rpm",
+		"repo_type": "remote",
+		"base_url": %q,
+		"mirrorlist": [%q],
+		"stale_on_error": false
+	}`, name, mockUpstreamA(), mockUpstreamB()))
+	defer deleteRepo(t, name)
+
+	seenA, seenB := false, false
+	const n = 12
+	for i := 0; i < n; i++ {
+		url := api(fmt.Sprintf("/api/v1/remote/%s/rr/%d", name, i))
+		resp, body := doRequest(t, http.MethodGet, url, nil, "")
+		if resp.StatusCode != http.StatusOK {
+			t.Fatalf("request %d: status %d: %s", i, resp.StatusCode, body)
+		}
+		switch strings.TrimSpace(string(body)) {
+		case "UPSTREAM-A":
+			seenA = true
+		case "UPSTREAM-B":
+			seenB = true
+		default:
+			t.Fatalf("request %d: unexpected body %q", i, body)
+		}
+	}
+	if !seenA || !seenB {
+		t.Fatalf("round-robin did not reach both upstreams: A=%v B=%v", seenA, seenB)
+	}
+}
+
+// TestMultiBaseURLFailover points a two-mirror remote at a dead primary and a
+// healthy secondary and asserts every request still succeeds via the secondary.
+func TestMultiBaseURLFailover(t *testing.T) {
+	name := "e2e-failover"
+	createRepo(t, fmt.Sprintf(`{
+		"name": %q,
+		"package_type": "rpm",
+		"repo_type": "remote",
+		"base_url": "http://mockupstream-dead:80",
+		"mirrorlist": [%q],
+		"stale_on_error": false
+	}`, name, mockUpstreamB()))
+	defer deleteRepo(t, name)
+
+	for i := 0; i < 6; i++ {
+		url := api(fmt.Sprintf("/api/v1/remote/%s/fo/%d", name, i))
+		resp, body := doRequest(t, http.MethodGet, url, nil, "")
+		if resp.StatusCode != http.StatusOK {
+			t.Fatalf("request %d: dead primary broke fetch: status %d: %s", i, resp.StatusCode, body)
+		}
+		if got := strings.TrimSpace(string(body)); got != "UPSTREAM-B" {
+			t.Fatalf("request %d: body %q, want UPSTREAM-B (served via failover)", i, got)
+		}
+	}
+}
+
+// TestSingleBaseURLRegression asserts a remote with no mirrorlist works exactly
+// as before the mirrorlist change.
+func TestSingleBaseURLRegression(t *testing.T) {
+	name := "e2e-single"
+	createRepo(t, fmt.Sprintf(`{
+		"name": %q,
+		"package_type": "rpm",
+		"repo_type": "remote",
+		"base_url": %q,
+		"stale_on_error": false
+	}`, name, mockUpstreamA()))
+	defer deleteRepo(t, name)
+
+	resp, body := doRequest(t, http.MethodGet, api("/api/v1/remote/"+name+"/solo/0"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("single-url fetch: status %d: %s", resp.StatusCode, body)
+	}
+	if got := strings.TrimSpace(string(body)); got != "UPSTREAM-A" {
+		t.Fatalf("single-url body %q, want UPSTREAM-A", got)
+	}
+}
+
+// TestMultiBaseURLDnfFailover drives a real dnf (stock rockylinux container) at
+// a two-mirror rpm remote whose primary is dead: makecache + install must
+// succeed via the live secondary mirror, proving a dead mirror does not break a
+// real package-manager client. Requires the compose network and internal API
+// URL exported by scripts/docker-e2e.sh; skipped when run standalone.
+func TestMultiBaseURLDnfFailover(t *testing.T) {
+	network := os.Getenv("COMPOSE_NETWORK")
+	internal := os.Getenv("ARTIFACTAPI_INTERNAL")
+	if network == "" || internal == "" {
+		t.Skip("COMPOSE_NETWORK/ARTIFACTAPI_INTERNAL not set; run via scripts/docker-e2e.sh")
+	}
+	if _, err := exec.LookPath("docker"); err != nil {
+		t.Skip("docker not available on the test host")
+	}
+
+	name := "e2e-dnf-failover"
+	// Primary base_url is dead; the live mirror serves the real yum repo under
+	// fixtures/rpm-mirror via the shared mock upstream.
+	createRepo(t, fmt.Sprintf(`{
+		"name": %q,
+		"package_type": "rpm",
+		"repo_type": "remote",
+		"base_url": "http://mockupstream-dead:80",
+		"mirrorlist": [%q],
+		"stale_on_error": false
+	}`, name, mockUpstream()))
+	defer deleteRepo(t, name)
+
+	repoURL := strings.TrimRight(internal, "/") + "/api/v1/remote/" + name + "/rpm-mirror"
+	repoConf := fmt.Sprintf("[dnffo]\nname=dnffo\nbaseurl=%s\nenabled=1\ngpgcheck=0\nsslverify=0\nmetadata_expire=0\n", repoURL)
+	script := "set -euo pipefail; " +
+		"printf '%s' \"$REPO\" > /etc/yum.repos.d/dnffo.repo; " +
+		"dnf -y --disablerepo='*' --enablerepo=dnffo makecache; " +
+		"dnf -y --disablerepo='*' --enablerepo=dnffo install e2e-testpkg; " +
+		"rpm -q e2e-testpkg"
+
+	cmd := exec.Command("docker", "run", "--rm",
+		"--network", network,
+		"-e", "REPO="+repoConf,
+		"rockylinux:9", "bash", "-c", script)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("real dnf install through a dead primary mirror failed: %v\n%s", err, out)
+	}
+	if !strings.Contains(string(out), "e2e-testpkg-1.0-1") {
+		t.Fatalf("dnf did not install the expected package via failover; output:\n%s", out)
+	}
+}

e2e-docker/repos_test.go

@@ -0,0 +1,134 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+)
+
+func TestHealth(t *testing.T) {
+	resp, body := doRequest(t, http.MethodGet, api("/health"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("health: status %d: %s", resp.StatusCode, body)
+	}
+}
+
+// TestRemoteLifecycle covers add/change/delete for a remote repository.
+func TestRemoteLifecycle(t *testing.T) {
+	createRepo(t, `{
+		"name": "crud-remote",
+		"package_type": "generic",
+		"repo_type": "remote",
+		"base_url": "https://example.com",
+		"mutable_ttl": 600,
+		"stale_on_error": true
+	}`)
+	defer deleteRepo(t, "crud-remote")
+
+	got := getRepo(t, "crud-remote")
+	if got["base_url"] != "https://example.com" || got["mutable_ttl"].(float64) != 600 {
+		t.Fatalf("unexpected created remote: %v", got)
+	}
+
+	// change
+	resp, body := doRequest(t, http.MethodPut, api("/api/v2/remotes/crud-remote"), []byte(`{
+		"package_type": "generic",
+		"base_url": "https://updated.example.com",
+		"mutable_ttl": 120,
+		"stale_on_error": true
+	}`), "application/json")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("update remote: status %d: %s", resp.StatusCode, body)
+	}
+	got = getRepo(t, "crud-remote")
+	if got["base_url"] != "https://updated.example.com" || got["mutable_ttl"].(float64) != 120 {
+		t.Fatalf("update not applied: %v", got)
+	}
+
+	// delete
+	resp, _ = doRequest(t, http.MethodDelete, api("/api/v2/remotes/crud-remote"), nil, "")
+	if resp.StatusCode != http.StatusNoContent {
+		t.Fatalf("delete remote: status %d", resp.StatusCode)
+	}
+	resp, _ = doRequest(t, http.MethodGet, api("/api/v2/remotes/crud-remote"), nil, "")
+	if resp.StatusCode != http.StatusNotFound {
+		t.Fatalf("expected 404 after delete, got %d", resp.StatusCode)
+	}
+}
+
+// TestLocalLifecycle covers add/delete for a local repository.
+func TestLocalLifecycle(t *testing.T) {
+	createRepo(t, `{
+		"name": "crud-local",
+		"package_type": "generic",
+		"repo_type": "local"
+	}`)
+	defer deleteRepo(t, "crud-local")
+
+	got := getRepo(t, "crud-local")
+	if got["repo_type"] != "local" {
+		t.Fatalf("expected repo_type local, got %v", got["repo_type"])
+	}
+
+	resp, _ := doRequest(t, http.MethodDelete, api("/api/v2/remotes/crud-local"), nil, "")
+	if resp.StatusCode != http.StatusNoContent {
+		t.Fatalf("delete local: status %d", resp.StatusCode)
+	}
+}
+
+// TestVirtualLifecycle covers add/change/delete for a virtual repository.
+func TestVirtualLifecycle(t *testing.T) {
+	createRepo(t, `{"name":"vmem-a","package_type":"helm","repo_type":"remote","base_url":"https://a.example.com","stale_on_error":true}`)
+	createRepo(t, `{"name":"vmem-b","package_type":"helm","repo_type":"remote","base_url":"https://b.example.com","stale_on_error":true}`)
+	defer deleteRepo(t, "vmem-a")
+	defer deleteRepo(t, "vmem-b")
+
+	createVirtual(t, `{
+		"name": "crud-virtual",
+		"package_type": "helm",
+		"members": ["vmem-a"]
+	}`)
+	defer deleteVirtual(t, "crud-virtual")
+
+	// change members
+	resp, body := doRequest(t, http.MethodPut, api("/api/v2/virtuals/crud-virtual"), []byte(`{
+		"package_type": "helm",
+		"members": ["vmem-a", "vmem-b"]
+	}`), "application/json")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("update virtual: status %d: %s", resp.StatusCode, body)
+	}
+
+	resp, body = doRequest(t, http.MethodGet, api("/api/v2/virtuals/crud-virtual"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("get virtual: status %d: %s", resp.StatusCode, body)
+	}
+	var v map[string]any
+	if err := json.Unmarshal(body, &v); err != nil {
+		t.Fatalf("decode virtual: %v", err)
+	}
+	members, _ := v["members"].([]any)
+	if len(members) != 2 {
+		t.Fatalf("expected 2 members after update, got %v", v["members"])
+	}
+
+	resp, _ = doRequest(t, http.MethodDelete, api("/api/v2/virtuals/crud-virtual"), nil, "")
+	if resp.StatusCode != http.StatusNoContent {
+		t.Fatalf("delete virtual: status %d", resp.StatusCode)
+	}
+}
+
+func getRepo(t *testing.T, name string) map[string]any {
+	t.Helper()
+	resp, body := doRequest(t, http.MethodGet, api("/api/v2/remotes/"+name), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("get remote %s: status %d: %s", name, resp.StatusCode, body)
+	}
+	var m map[string]any
+	if err := json.Unmarshal(body, &m); err != nil {
+		t.Fatalf("decode remote %s: %v", name, err)
+	}
+	return m
+}

e2e-docker/virtual_test.go

@@ -0,0 +1,54 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+)
+
+// TestVirtualPyPIMerge uploads different packages to two pypi locals and
+// checks that a virtual over them serves a merged simple index.
+func TestVirtualPyPIMerge(t *testing.T) {
+	createRepo(t, `{"name":"pmerge-a","package_type":"pypi","repo_type":"local"}`)
+	createRepo(t, `{"name":"pmerge-b","package_type":"pypi","repo_type":"local"}`)
+	defer deleteRepo(t, "pmerge-a")
+	defer deleteRepo(t, "pmerge-b")
+
+	uploadFile(t, "pmerge-a", "foo-1.0-py3-none-any.whl", fixtureBytes(t, "packages/foo-1.0-py3-none-any.whl"), "application/zip")
+	uploadFile(t, "pmerge-b", "bar-2.0-py3-none-any.whl", []byte("bar wheel payload"), "application/zip")
+
+	createVirtual(t, `{"name":"pmerge-v","package_type":"pypi","members":["pmerge-a","pmerge-b"]}`)
+	defer deleteVirtual(t, "pmerge-v")
+
+	resp, body := doRequest(t, http.MethodGet, api("/api/v1/virtual/pmerge-v/simple/"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("virtual simple index: status %d: %s", resp.StatusCode, body)
+	}
+	s := string(body)
+	if !strings.Contains(s, "foo") || !strings.Contains(s, "bar") {
+		t.Fatalf("merged index missing a member package (want foo and bar): %s", s)
+	}
+}
+
+// TestVirtualHelmMerge points two helm remotes at mock index.yaml documents
+// with distinct charts and checks the virtual merges both into one index.
+func TestVirtualHelmMerge(t *testing.T) {
+	createRepo(t, `{"name":"hmerge-a","package_type":"helm","repo_type":"remote","base_url":"`+mockUpstream()+`/helm-a","stale_on_error":true}`)
+	createRepo(t, `{"name":"hmerge-b","package_type":"helm","repo_type":"remote","base_url":"`+mockUpstream()+`/helm-b","stale_on_error":true}`)
+	defer deleteRepo(t, "hmerge-a")
+	defer deleteRepo(t, "hmerge-b")
+
+	createVirtual(t, `{"name":"hmerge-v","package_type":"helm","members":["hmerge-a","hmerge-b"]}`)
+	defer deleteVirtual(t, "hmerge-v")
+
+	resp, body := doRequest(t, http.MethodGet, api("/api/v1/virtual/hmerge-v/index.yaml"), nil, "")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("virtual index.yaml: status %d: %s", resp.StatusCode, body)
+	}
+	s := string(body)
+	if !strings.Contains(s, "alpha") || !strings.Contains(s, "beta") {
+		t.Fatalf("merged helm index missing a member chart (want alpha and beta): %s", s)
+	}
+}

e2e/e2e_test.go

@@ -95,7 +95,7 @@ func TestMain(m *testing.M) {
 	}
 	cfg.ListenAddr = "127.0.0.1:0"
 
-	srv, err := server.New(cfg)
+	srv, err := server.New(cfg, "e2e-test")
 	if err != nil {
 		log.Fatalf("server: %v", err)
 	}

e2e/management_test.go

@@ -24,6 +24,30 @@ func TestRoot(t *testing.T) {
 	}
 }
 
+func TestRemoteUpstreamTimeouts(t *testing.T) {
+	createRemote(t, `{
+		"name": "timeout-test",
+		"package_type": "generic",
+		"base_url": "https://example.com",
+		"stale_on_error": true,
+		"upstream_dial_timeout": 3,
+		"upstream_tls_timeout": 4,
+		"upstream_response_header_timeout": 5
+	}`)
+	defer deleteRemote(t, "timeout-test")
+
+	remote := getJSON(t, apiURL("/api/v2/remotes/timeout-test"))
+	for field, want := range map[string]float64{
+		"upstream_dial_timeout":            3,
+		"upstream_tls_timeout":             4,
+		"upstream_response_header_timeout": 5,
+	} {
+		if got, _ := remote[field].(float64); got != want {
+			t.Errorf("%s: got %v, want %v", field, remote[field], want)
+		}
+	}
+}
+
 func TestRemoteCRUD(t *testing.T) {
 	createRemote(t, `{
 		"name": "test-generic",

e2e/proxy_test.go

@@ -24,6 +24,39 @@ func TestProxyBlocklist(t *testing.T) {
 	assertStatus(t, apiURL("/api/v1/remote/blocklist-test/malware.exe"), http.StatusForbidden)
 }
 
+func TestProxyHeadBlocklist(t *testing.T) {
+	createRemote(t, `{
+		"name": "head-block-test",
+		"package_type": "generic",
+		"base_url": "https://example.com",
+		"blocklist": ["\\.exe$"],
+		"stale_on_error": true
+	}`)
+	defer deleteRemote(t, "head-block-test")
+
+	req, _ := http.NewRequest(http.MethodHead, apiURL("/v2/head-block-test/malware.exe"), nil)
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatalf("HEAD: %v", err)
+	}
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusForbidden {
+		t.Fatalf("HEAD blocklisted path: got %d, want 403", resp.StatusCode)
+	}
+}
+
+func TestProxyHeadUnknownRemote(t *testing.T) {
+	req, _ := http.NewRequest(http.MethodHead, apiURL("/v2/nonexistent/some/path"), nil)
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatalf("HEAD: %v", err)
+	}
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusNotFound {
+		t.Fatalf("HEAD unknown remote: got %d, want 404", resp.StatusCode)
+	}
+}
+
 func TestProxyPatterns(t *testing.T) {
 	createRemote(t, `{
 		"name": "patterns-test",

go.mod

@@ -7,12 +7,17 @@ require (
 	github.com/charmbracelet/bubbletea v1.3.10
 	github.com/charmbracelet/lipgloss v1.1.0
 	github.com/go-chi/chi/v5 v5.3.0
+	github.com/google/uuid v1.6.0
 	github.com/jackc/pgx/v5 v5.10.0
+	github.com/klauspost/compress v1.19.2
 	github.com/minio/minio-go/v7 v7.2.0
 	github.com/redis/go-redis/v9 v9.20.0
 	github.com/testcontainers/testcontainers-go v0.42.0
 	github.com/testcontainers/testcontainers-go/modules/postgres v0.42.0
 	github.com/testcontainers/testcontainers-go/modules/redis v0.42.0
+	github.com/ulikunitz/xz v0.5.16
+	golang.org/x/crypto v0.51.0
+	golang.org/x/time v0.15.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -45,11 +50,9 @@ require (
 	github.com/go-logr/logr v1.4.3 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-ole/go-ole v1.2.6 // indirect
-	github.com/google/uuid v1.6.0 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
 	github.com/jackc/puddle/v2 v2.2.2 // indirect
-	github.com/klauspost/compress v1.18.6 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.11 // indirect
 	github.com/klauspost/crc32 v1.3.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.4.0 // indirect
@@ -96,7 +99,6 @@ require (
 	go.opentelemetry.io/otel/trace v1.41.0 // indirect
 	go.uber.org/atomic v1.11.0 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
-	golang.org/x/crypto v0.51.0 // indirect
 	golang.org/x/net v0.53.0 // indirect
 	golang.org/x/sync v0.20.0 // indirect
 	golang.org/x/sys v0.44.0 // indirect

go.sum

@@ -85,8 +85,8 @@ github.com/jackc/pgx/v5 v5.10.0 h1:VhSvgU2jSli8o3AqIEOTJr7rZwAEUVo4E4XhR94Zfr0=
 github.com/jackc/pgx/v5 v5.10.0/go.mod h1:mal1tBGAFfLHvZzaYh77YS/eC6IX9OWbRV1QIIM0Jn4=
 github.com/jackc/puddle/v2 v2.2.2 h1:PR8nw+E/1w0GLuRFSmiioY6UooMp6KJv0/61nB7icHo=
 github.com/jackc/puddle/v2 v2.2.2/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
-github.com/klauspost/compress v1.18.6 h1:2jupLlAwFm95+YDR+NwD2MEfFO9d4z4Prjl1XXDjuao=
-github.com/klauspost/compress v1.18.6/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
+github.com/klauspost/compress v1.19.2 h1:hMRETovs/pu/dVWN7zIT1PGG8t509MwT6bO7XSi26R8=
+github.com/klauspost/compress v1.19.2/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
 github.com/klauspost/cpuid/v2 v2.0.1/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=
 github.com/klauspost/cpuid/v2 v2.2.11 h1:0OwqZRYI2rFrjS4kvkDnqJkKHdHaRnCm68/DY4OxRzU=
 github.com/klauspost/cpuid/v2 v2.2.11/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
@@ -189,6 +189,8 @@ github.com/tklauser/go-sysconf v0.3.16 h1:frioLaCQSsF5Cy1jgRBrzr6t502KIIwQ0MArYI
 github.com/tklauser/go-sysconf v0.3.16/go.mod h1:/qNL9xxDhc7tx3HSRsLWNnuzbVfh3e7gh/BmM179nYI=
 github.com/tklauser/numcpus v0.11.0 h1:nSTwhKH5e1dMNsCdVBukSZrURJRoHbSEQjdEbY+9RXw=
 github.com/tklauser/numcpus v0.11.0/go.mod h1:z+LwcLq54uWZTX0u/bGobaV34u6V7KNlTZejzM6/3MQ=
+github.com/ulikunitz/xz v0.5.16 h1:ld6NyySjx5lowVKwJvMRLnW5nxKX/xnpSiFYZ/Lxur0=
+github.com/ulikunitz/xz v0.5.16/go.mod h1:H9Rt/W6/Qj27PGauhQc6nfCDy7vHpzsOThBSaYDoEhw=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
 github.com/yusufpapurcu/wmi v1.2.4 h1:zFUKzehAFReQwLys1b/iSMl+JQGSCSjtVqQn9bBrPo0=
@@ -234,6 +236,8 @@ golang.org/x/term v0.43.0 h1:S4RLU2sB31O/NCl+zFN9Aru9A/Cq2aqKpTZJ6B+DwT4=
 golang.org/x/term v0.43.0/go.mod h1:lrhlHNdQJHO+1qVYiHfFKVuVioJIheAc3fBSMFYEIsk=
 golang.org/x/text v0.37.0 h1:Cqjiwd9eSg8e0QAkyCaQTNHFIIzWtidPahFWR83rTrc=
 golang.org/x/text v0.37.0/go.mod h1:a5sjxXGs9hsn/AJVwuElvCAo9v8QYLzvavO5z2PiM38=
+golang.org/x/time v0.15.0 h1:bbrp8t3bGUeFOx08pvsMYRTCVSMk89u4tKbNOZbp88U=
+golang.org/x/time v0.15.0/go.mod h1:Y4YMaQmXwGQZoFaVFk4YpCt4FLQMYKZe9oeV/f4MSno=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=

internal/api/terraform/registry.go

@@ -0,0 +1,301 @@
+// Package terraform serves local terraform repos as a real Terraform provider
+// registry: service discovery, version listing, and GPG-signed downloads, so
+// `terraform init` installs from a bare source address with no client config.
+package terraform
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"path"
+	"sort"
+	"strings"
+
+	"github.com/go-chi/chi/v5"
+
+	"git.unkin.net/unkin/artifactapi/internal/database"
+	tfprov "git.unkin.net/unkin/artifactapi/internal/provider/terraform"
+	"git.unkin.net/unkin/artifactapi/internal/tfsign"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// ProvidersV1Path is the base the service-discovery document advertises (Terraform
+// appends "{namespace}/{type}/versions" etc). MountPath is the same prefix without
+// the trailing slash, for chi.Mount.
+const (
+	ProvidersV1Path = "/terraform/v1/providers/"
+	MountPath       = "/terraform/v1/providers"
+)
+
+type Handler struct {
+	db        *database.DB
+	signer    *tfsign.Signer
+	protocols []string
+}
+
+func NewHandler(db *database.DB, signer *tfsign.Signer, protocols string) *Handler {
+	var protos []string
+	for _, p := range strings.Split(protocols, ",") {
+		if p = strings.TrimSpace(p); p != "" {
+			protos = append(protos, p)
+		}
+	}
+	if len(protos) == 0 {
+		protos = []string{"5.0", "6.0"}
+	}
+	return &Handler{db: db, signer: signer, protocols: protos}
+}
+
+// Enabled reports whether a signing key is configured. Without one the registry
+// cannot produce the signed SHA256SUMS the protocol requires, so it stays off.
+func (h *Handler) Enabled() bool { return h.signer != nil }
+
+func (h *Handler) Routes() chi.Router {
+	r := chi.NewRouter()
+	r.Get("/{namespace}/{type}/versions", h.versions)
+	r.Get("/{namespace}/{type}/{version}/download/{os}/{arch}", h.download)
+	r.Get("/{namespace}/{type}/{version}/sha256sums", h.sha256sums)
+	r.Get("/{namespace}/{type}/{version}/sha256sums.sig", h.sha256sumsSig)
+	return r
+}
+
+// ServiceDiscovery answers /.well-known/terraform.json, pointing Terraform at the
+// providers.v1 protocol base.
+func (h *Handler) ServiceDiscovery(w http.ResponseWriter, r *http.Request) {
+	if !h.Enabled() {
+		http.NotFound(w, r)
+		return
+	}
+	writeJSON(w, map[string]string{"providers.v1": ProvidersV1Path})
+}
+
+// providerFile is one resolved platform artifact within a repo.
+type providerFile struct {
+	version  string
+	os       string
+	arch     string
+	filePath string // path within the repo, e.g. unkin/artifactapi/...zip
+	sha256   string // hex, no "sha256:" prefix
+}
+
+// resolve finds every provider zip of the given type in the repo (namespace).
+// The Terraform source namespace maps to the artifactapi repo name; the provider
+// is matched by type across whatever in-repo folder it was uploaded under.
+func (h *Handler) resolve(r *http.Request, namespace, typeName string) ([]providerFile, error) {
+	remote, err := h.db.GetRemote(r.Context(), namespace)
+	if err != nil || remote.PackageType != models.PackageTerraform {
+		return nil, nil
+	}
+
+	rows, err := h.db.ListLocalFiles(r.Context(), namespace, 10000, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	var out []providerFile
+	for _, row := range rows {
+		parsed := tfprov.ParseProviderZip(path.Base(row.FilePath))
+		if !parsed.Ok || parsed.Type != typeName {
+			continue
+		}
+		out = append(out, providerFile{
+			version:  parsed.Version,
+			os:       parsed.OS,
+			arch:     parsed.Arch,
+			filePath: row.FilePath,
+			sha256:   strings.TrimPrefix(row.ContentHash, "sha256:"),
+		})
+	}
+	return out, nil
+}
+
+func (h *Handler) versions(w http.ResponseWriter, r *http.Request) {
+	if !h.Enabled() {
+		http.NotFound(w, r)
+		return
+	}
+	namespace := chi.URLParam(r, "namespace")
+	typeName := chi.URLParam(r, "type")
+
+	files, err := h.resolve(r, namespace, typeName)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	if len(files) == 0 {
+		http.NotFound(w, r)
+		return
+	}
+
+	// Group platforms by version, de-duplicated and stably ordered.
+	type platform struct {
+		OS   string `json:"os"`
+		Arch string `json:"arch"`
+	}
+	platforms := map[string]map[string]platform{}
+	for _, f := range files {
+		if platforms[f.version] == nil {
+			platforms[f.version] = map[string]platform{}
+		}
+		platforms[f.version][f.os+"_"+f.arch] = platform{OS: f.os, Arch: f.arch}
+	}
+
+	type versionEntry struct {
+		Version   string     `json:"version"`
+		Protocols []string   `json:"protocols"`
+		Platforms []platform `json:"platforms"`
+	}
+	out := struct {
+		Versions []versionEntry `json:"versions"`
+	}{}
+	for version, plats := range platforms {
+		entry := versionEntry{Version: version, Protocols: h.protocols}
+		for _, p := range plats {
+			entry.Platforms = append(entry.Platforms, p)
+		}
+		sort.Slice(entry.Platforms, func(i, j int) bool {
+			return entry.Platforms[i].OS+entry.Platforms[i].Arch < entry.Platforms[j].OS+entry.Platforms[j].Arch
+		})
+		out.Versions = append(out.Versions, entry)
+	}
+	sort.Slice(out.Versions, func(i, j int) bool { return out.Versions[i].Version < out.Versions[j].Version })
+
+	writeJSON(w, out)
+}
+
+func (h *Handler) download(w http.ResponseWriter, r *http.Request) {
+	if !h.Enabled() {
+		http.NotFound(w, r)
+		return
+	}
+	namespace := chi.URLParam(r, "namespace")
+	typeName := chi.URLParam(r, "type")
+	version := chi.URLParam(r, "version")
+	osName := chi.URLParam(r, "os")
+	arch := chi.URLParam(r, "arch")
+
+	files, err := h.resolve(r, namespace, typeName)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	var match *providerFile
+	for i := range files {
+		if files[i].version == version && files[i].os == osName && files[i].arch == arch {
+			match = &files[i]
+			break
+		}
+	}
+	if match == nil {
+		http.NotFound(w, r)
+		return
+	}
+
+	base := baseURL(r)
+	verBase := fmt.Sprintf("%s%s/%s/%s", base+ProvidersV1Path, namespace, typeName, version)
+
+	type gpgKey struct {
+		KeyID      string `json:"key_id"`
+		ASCIIArmor string `json:"ascii_armor"`
+	}
+	resp := struct {
+		Protocols           []string `json:"protocols"`
+		OS                  string   `json:"os"`
+		Arch                string   `json:"arch"`
+		Filename            string   `json:"filename"`
+		DownloadURL         string   `json:"download_url"`
+		SHASumsURL          string   `json:"shasums_url"`
+		SHASumsSignatureURL string   `json:"shasums_signature_url"`
+		SHASum              string   `json:"shasum"`
+		SigningKeys         struct {
+			GPGPublicKeys []gpgKey `json:"gpg_public_keys"`
+		} `json:"signing_keys"`
+	}{
+		Protocols:           h.protocols,
+		OS:                  match.os,
+		Arch:                match.arch,
+		Filename:            path.Base(match.filePath),
+		DownloadURL:         fmt.Sprintf("%s/api/v1/local/%s/%s", base, namespace, match.filePath),
+		SHASumsURL:          verBase + "/sha256sums",
+		SHASumsSignatureURL: verBase + "/sha256sums.sig",
+		SHASum:              match.sha256,
+	}
+	resp.SigningKeys.GPGPublicKeys = []gpgKey{{
+		KeyID:      h.signer.KeyID(),
+		ASCIIArmor: h.signer.PublicKeyArmor(),
+	}}
+
+	writeJSON(w, resp)
+}
+
+func (h *Handler) sha256sums(w http.ResponseWriter, r *http.Request) {
+	sums, ok := h.buildSums(w, r)
+	if !ok {
+		return
+	}
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	w.Write(sums)
+}
+
+func (h *Handler) sha256sumsSig(w http.ResponseWriter, r *http.Request) {
+	sums, ok := h.buildSums(w, r)
+	if !ok {
+		return
+	}
+	sig, err := h.signer.Sign(sums)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	w.Header().Set("Content-Type", "application/octet-stream")
+	w.Write(sig)
+}
+
+// buildSums renders the SHA256SUMS body for one version: one "<hex>  <filename>"
+// line per platform zip, sorted by filename so the signed bytes are stable.
+func (h *Handler) buildSums(w http.ResponseWriter, r *http.Request) ([]byte, bool) {
+	if !h.Enabled() {
+		http.NotFound(w, r)
+		return nil, false
+	}
+	namespace := chi.URLParam(r, "namespace")
+	typeName := chi.URLParam(r, "type")
+	version := chi.URLParam(r, "version")
+
+	files, err := h.resolve(r, namespace, typeName)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return nil, false
+	}
+
+	var lines []string
+	for _, f := range files {
+		if f.version != version {
+			continue
+		}
+		lines = append(lines, fmt.Sprintf("%s  %s", f.sha256, path.Base(f.filePath)))
+	}
+	if len(lines) == 0 {
+		http.NotFound(w, r)
+		return nil, false
+	}
+	sort.Strings(lines)
+	return []byte(strings.Join(lines, "\n") + "\n"), true
+}
+
+func writeJSON(w http.ResponseWriter, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(v)
+}
+
+func baseURL(r *http.Request) string {
+	scheme := "http"
+	if r.TLS != nil {
+		scheme = "https"
+	}
+	if fwd := r.Header.Get("X-Forwarded-Proto"); fwd != "" {
+		scheme = fwd
+	}
+	return scheme + "://" + r.Host
+}

internal/api/terraform/registry_test.go

@@ -0,0 +1,186 @@
+package terraform
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/go-chi/chi/v5"
+	"golang.org/x/crypto/openpgp"
+	"golang.org/x/crypto/openpgp/armor"
+
+	"git.unkin.net/unkin/artifactapi/internal/database"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+	"git.unkin.net/unkin/artifactapi/internal/tfsign"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+var testDSN string
+
+func TestMain(m *testing.M) {
+	ctx := context.Background()
+	dsn, terminate, err := testsupport.StartPostgres(ctx)
+	if err != nil {
+		os.Exit(m.Run())
+	}
+	testDSN = dsn
+	code := m.Run()
+	terminate()
+	os.Exit(code)
+}
+
+// testSigner writes a throwaway armored key and loads it.
+func testSigner(t *testing.T) *tfsign.Signer {
+	t.Helper()
+	e, err := openpgp.NewEntity("artifactapi test", "tf", "tf@example.com", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var buf bytes.Buffer
+	w, _ := armor.Encode(&buf, openpgp.PrivateKeyType, nil)
+	if err := e.SerializePrivate(w, nil); err != nil {
+		t.Fatal(err)
+	}
+	w.Close()
+	p := filepath.Join(t.TempDir(), "private-key.asc")
+	if err := os.WriteFile(p, buf.Bytes(), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	s, err := tfsign.Load(p, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	return s
+}
+
+func TestProviderRegistryFlow(t *testing.T) {
+	if testDSN == "" {
+		t.Skip("Docker unavailable")
+	}
+	ctx := context.Background()
+	db, err := database.New(testDSN)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	const repo = "tf-reg" // Terraform namespace == repo name
+	const filePath = "unkin/artifactapi/terraform-provider-artifactapi_1.2.3_linux_amd64.zip"
+	const hash = "sha256:983cdb25cb7b976538e4334d26e52dee5f44749b9be1500c760cf5cf66be659b"
+	const wantSha = "983cdb25cb7b976538e4334d26e52dee5f44749b9be1500c760cf5cf66be659b"
+
+	if err := db.CreateRemote(ctx, &models.Remote{Name: repo, PackageType: models.PackageTerraform, RepoType: models.RepoTypeLocal}); err != nil {
+		t.Fatal(err)
+	}
+	if err := db.UpsertBlob(ctx, hash, "blobs/98/3c", 6381007, "application/zip"); err != nil {
+		t.Fatal(err)
+	}
+	if err := db.CreateLocalFile(ctx, repo, filePath, hash); err != nil {
+		t.Fatal(err)
+	}
+
+	signer := testSigner(t)
+	h := NewHandler(db, signer, "5.0,6.0")
+	router := chi.NewRouter()
+	router.Get("/.well-known/terraform.json", h.ServiceDiscovery)
+	router.Mount(MountPath, h.Routes())
+
+	get := func(p string) *httptest.ResponseRecorder {
+		req := httptest.NewRequest("GET", p, nil)
+		w := httptest.NewRecorder()
+		router.ServeHTTP(w, req)
+		return w
+	}
+
+	// Service discovery.
+	w := get("/.well-known/terraform.json")
+	if w.Code != 200 {
+		t.Fatalf("discovery = %d", w.Code)
+	}
+	var disc map[string]string
+	json.Unmarshal(w.Body.Bytes(), &disc)
+	if disc["providers.v1"] != ProvidersV1Path {
+		t.Errorf("providers.v1 = %q", disc["providers.v1"])
+	}
+
+	// Versions.
+	w = get("/terraform/v1/providers/tf-reg/artifactapi/versions")
+	if w.Code != 200 {
+		t.Fatalf("versions = %d %s", w.Code, w.Body)
+	}
+	var vresp struct {
+		Versions []struct {
+			Version   string              `json:"version"`
+			Protocols []string            `json:"protocols"`
+			Platforms []map[string]string `json:"platforms"`
+		} `json:"versions"`
+	}
+	json.Unmarshal(w.Body.Bytes(), &vresp)
+	if len(vresp.Versions) != 1 || vresp.Versions[0].Version != "1.2.3" {
+		t.Fatalf("unexpected versions: %+v", vresp)
+	}
+	if len(vresp.Versions[0].Platforms) != 1 || vresp.Versions[0].Platforms[0]["os"] != "linux" {
+		t.Fatalf("unexpected platforms: %+v", vresp.Versions[0].Platforms)
+	}
+
+	// Download.
+	w = get("/terraform/v1/providers/tf-reg/artifactapi/1.2.3/download/linux/amd64")
+	if w.Code != 200 {
+		t.Fatalf("download = %d %s", w.Code, w.Body)
+	}
+	var dl struct {
+		Filename            string `json:"filename"`
+		DownloadURL         string `json:"download_url"`
+		SHASumsURL          string `json:"shasums_url"`
+		SHASumsSignatureURL string `json:"shasums_signature_url"`
+		SHASum              string `json:"shasum"`
+		SigningKeys         struct {
+			GPGPublicKeys []struct {
+				KeyID      string `json:"key_id"`
+				ASCIIArmor string `json:"ascii_armor"`
+			} `json:"gpg_public_keys"`
+		} `json:"signing_keys"`
+	}
+	json.Unmarshal(w.Body.Bytes(), &dl)
+	if dl.SHASum != wantSha {
+		t.Errorf("shasum = %q", dl.SHASum)
+	}
+	wantURL := "http://example.com/api/v1/local/tf-reg/" + filePath
+	if dl.DownloadURL != wantURL {
+		t.Errorf("download_url = %q, want %q", dl.DownloadURL, wantURL)
+	}
+	if len(dl.SigningKeys.GPGPublicKeys) != 1 || dl.SigningKeys.GPGPublicKeys[0].KeyID != signer.KeyID() {
+		t.Errorf("signing key mismatch: %+v", dl.SigningKeys)
+	}
+
+	// SHA256SUMS + signature verify against the advertised key.
+	sums := get("/terraform/v1/providers/tf-reg/artifactapi/1.2.3/sha256sums")
+	wantLine := wantSha + "  terraform-provider-artifactapi_1.2.3_linux_amd64.zip\n"
+	if sums.Body.String() != wantLine {
+		t.Errorf("sha256sums = %q, want %q", sums.Body.String(), wantLine)
+	}
+	sig := get("/terraform/v1/providers/tf-reg/artifactapi/1.2.3/sha256sums.sig")
+	keyring, err := openpgp.ReadArmoredKeyRing(bytes.NewReader([]byte(dl.SigningKeys.GPGPublicKeys[0].ASCIIArmor)))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := openpgp.CheckDetachedSignature(keyring, bytes.NewReader(sums.Body.Bytes()), bytes.NewReader(sig.Body.Bytes())); err != nil {
+		t.Errorf("sha256sums.sig did not verify: %v", err)
+	}
+}
+
+func TestRegistryDisabledWithoutSigner(t *testing.T) {
+	h := NewHandler(nil, nil, "")
+	router := chi.NewRouter()
+	router.Get("/.well-known/terraform.json", h.ServiceDiscovery)
+	req := httptest.NewRequest("GET", "/.well-known/terraform.json", nil)
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+	if w.Code != 404 {
+		t.Errorf("disabled discovery = %d, want 404", w.Code)
+	}
+}

internal/api/v1/docker.go

@@ -0,0 +1,486 @@
+package v1
+
+import (
+	"bytes"
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"os"
+	"sort"
+	"strings"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/google/uuid"
+
+	"git.unkin.net/unkin/artifactapi/internal/database"
+	"git.unkin.net/unkin/artifactapi/internal/storage"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// This file implements the write half of the Docker Registry HTTP API V2 for
+// *local* docker repositories, so a `docker push` / `docker pull` against
+// artifactapi treats a local docker repo as a genuine registry (matching the
+// project's "local repos are the real thing" principle) rather than a mirror.
+//
+// Storage reuses the existing content-addressable primitives:
+//   - blob and manifest bytes are stored via the CAS (deduplicated by sha256)
+//   - a local_files row per (repo, "<image>/blobs/<digest>") and
+//     (repo, "<image>/manifests/<ref>") keeps the blob referenced so the GC
+//     does not reap it, and lets pulls resolve a reference back to a blob.
+// Tags are mutable references (UpsertLocalFile); digests and blobs are
+// immutable (CreateLocalFile, tolerating an already-exists on re-push).
+
+const dockerAPIVersionHeader = "registry/2.0"
+
+// Chunked blob uploads are staged in object storage under uploads/<uuid> rather
+// than in process memory, so the POST / PATCH / PUT of a single push can each be
+// served by a different replica (the API runs with minReplicas>1 and no session
+// affinity). The upload UUID travels in the Location URL handed back to the
+// client, so any replica reconstructs the staging key with no shared in-process
+// state. Abandoned stages are dropped by the GC's uploads sweep.
+func uploadKey(id string) string { return "uploads/" + id }
+
+var errUploadUnknown = errors.New("unknown upload")
+
+// appendUpload appends a chunk to the staged upload object and returns the new
+// total size. The staged bytes live entirely in object storage (download,
+// append to a per-request temp file, re-upload), which keeps the session state
+// replica-independent. Docker sends the whole layer in one PATCH, so this is a
+// single append in the common case.
+func (h *ProxyHandler) appendUpload(ctx context.Context, id string, chunk io.Reader) (int64, error) {
+	key := uploadKey(id)
+	reader, info, err := h.store.Download(ctx, key)
+	if err != nil {
+		return 0, errUploadUnknown
+	}
+
+	tmp, err := os.CreateTemp("", "docker-upload-*")
+	if err != nil {
+		reader.Close()
+		return 0, err
+	}
+	defer os.Remove(tmp.Name())
+	defer tmp.Close()
+
+	if _, err := io.Copy(tmp, reader); err != nil {
+		reader.Close()
+		return 0, err
+	}
+	reader.Close()
+
+	n, err := io.Copy(tmp, chunk)
+	if err != nil {
+		return 0, err
+	}
+	size := info.Size + n
+	if _, err := tmp.Seek(0, io.SeekStart); err != nil {
+		return 0, err
+	}
+	if err := h.store.Upload(ctx, key, tmp, size, "application/octet-stream"); err != nil {
+		return 0, err
+	}
+	return size, nil
+}
+
+// dockerReq is a parsed /v2/<remote>/<image>/... request. kind is one of
+// "manifest", "blob", "upload", "tags".
+type dockerReq struct {
+	image string
+	kind  string
+	ref   string // tag, digest, or upload uuid depending on kind
+}
+
+// parseDockerPath splits the chi "*" remainder (everything after the repo name)
+// into the image name and the registry operation. The image name may itself
+// contain slashes, so operations are located by their well-known infixes.
+func parseDockerPath(rest string) (dockerReq, bool) {
+	rest = strings.TrimPrefix(rest, "/")
+	switch {
+	case strings.HasSuffix(rest, "/tags/list"):
+		return dockerReq{image: strings.TrimSuffix(rest, "/tags/list"), kind: "tags"}, true
+	case rest == "tags/list":
+		return dockerReq{}, false // no image
+	}
+	if i := strings.Index(rest, "/blobs/uploads"); i >= 0 {
+		image := rest[:i]
+		ref := strings.TrimPrefix(rest[i+len("/blobs/uploads"):], "/")
+		return dockerReq{image: image, kind: "upload", ref: ref}, image != ""
+	}
+	if i := strings.LastIndex(rest, "/manifests/"); i >= 0 {
+		return dockerReq{image: rest[:i], kind: "manifest", ref: rest[i+len("/manifests/"):]}, true
+	}
+	if i := strings.LastIndex(rest, "/blobs/"); i >= 0 {
+		return dockerReq{image: rest[:i], kind: "blob", ref: rest[i+len("/blobs/"):]}, true
+	}
+	return dockerReq{}, false
+}
+
+func isDigest(ref string) bool { return strings.HasPrefix(ref, "sha256:") }
+
+// localDockerRemote returns the repo if name is a local docker repository.
+func (h *ProxyHandler) localDockerRemote(r *http.Request, name string) (*models.Remote, bool) {
+	remote, err := h.db.GetRemote(r.Context(), name)
+	if err != nil {
+		return nil, false
+	}
+	return remote, remote.RepoType == models.RepoTypeLocal && remote.PackageType == models.PackageDocker
+}
+
+func dockerError(w http.ResponseWriter, status int, code, msg string) {
+	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Docker-Distribution-Api-Version", dockerAPIVersionHeader)
+	w.WriteHeader(status)
+	fmt.Fprintf(w, `{"errors":[{"code":%q,"message":%q}]}`, code, msg)
+}
+
+// dockerGet dispatches a registry GET to the local handler for local docker
+// repos and falls through to the upstream proxy for everything else.
+func (h *ProxyHandler) dockerGet(w http.ResponseWriter, r *http.Request) {
+	name := chi.URLParam(r, "remoteName")
+	if remote, ok := h.localDockerRemote(r, name); ok {
+		h.dockerLocalGet(w, r, remote, false)
+		return
+	}
+	h.handleProxy(w, r)
+}
+
+func (h *ProxyHandler) dockerHead(w http.ResponseWriter, r *http.Request) {
+	name := chi.URLParam(r, "remoteName")
+	if remote, ok := h.localDockerRemote(r, name); ok {
+		h.dockerLocalGet(w, r, remote, true)
+		return
+	}
+	h.handleProxyHead(w, r)
+}
+
+func (h *ProxyHandler) dockerPost(w http.ResponseWriter, r *http.Request) {
+	name := chi.URLParam(r, "remoteName")
+	remote, ok := h.localDockerRemote(r, name)
+	if !ok {
+		dockerError(w, http.StatusMethodNotAllowed, "UNSUPPORTED", "push is only supported for local docker repositories")
+		return
+	}
+	h.dockerStartUpload(w, r, remote)
+}
+
+func (h *ProxyHandler) dockerPatch(w http.ResponseWriter, r *http.Request) {
+	name := chi.URLParam(r, "remoteName")
+	remote, ok := h.localDockerRemote(r, name)
+	if !ok {
+		dockerError(w, http.StatusMethodNotAllowed, "UNSUPPORTED", "push is only supported for local docker repositories")
+		return
+	}
+	h.dockerPatchUpload(w, r, remote)
+}
+
+func (h *ProxyHandler) dockerPut(w http.ResponseWriter, r *http.Request) {
+	name := chi.URLParam(r, "remoteName")
+	remote, ok := h.localDockerRemote(r, name)
+	if !ok {
+		dockerError(w, http.StatusMethodNotAllowed, "UNSUPPORTED", "push is only supported for local docker repositories")
+		return
+	}
+	req, ok := parseDockerPath(chi.URLParam(r, "*"))
+	if !ok {
+		dockerError(w, http.StatusNotFound, "NAME_UNKNOWN", "unrecognised registry path")
+		return
+	}
+	switch req.kind {
+	case "upload":
+		h.dockerFinishUpload(w, r, remote, req)
+	case "manifest":
+		h.dockerPutManifest(w, r, remote, req)
+	default:
+		dockerError(w, http.StatusMethodNotAllowed, "UNSUPPORTED", "PUT not supported for this path")
+	}
+}
+
+func (h *ProxyHandler) dockerDelete(w http.ResponseWriter, r *http.Request) {
+	name := chi.URLParam(r, "remoteName")
+	remote, ok := h.localDockerRemote(r, name)
+	if !ok {
+		dockerError(w, http.StatusMethodNotAllowed, "UNSUPPORTED", "delete is only supported for local docker repositories")
+		return
+	}
+	req, ok := parseDockerPath(chi.URLParam(r, "*"))
+	if !ok {
+		dockerError(w, http.StatusNotFound, "NAME_UNKNOWN", "unrecognised registry path")
+		return
+	}
+	// Cancel an in-progress upload: drop its staging object.
+	if req.kind == "upload" && req.ref != "" {
+		_ = h.store.Delete(r.Context(), uploadKey(req.ref))
+		w.Header().Set("Docker-Distribution-Api-Version", dockerAPIVersionHeader)
+		w.WriteHeader(http.StatusNoContent)
+		return
+	}
+	if req.kind != "manifest" && req.kind != "blob" {
+		dockerError(w, http.StatusNotFound, "NAME_UNKNOWN", "unrecognised registry path")
+		return
+	}
+	filePath := req.image + "/" + req.kind + "s/" + req.ref
+	if err := h.db.DeleteLocalFile(r.Context(), remote.Name, filePath); err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	w.Header().Set("Docker-Distribution-Api-Version", dockerAPIVersionHeader)
+	w.WriteHeader(http.StatusAccepted)
+}
+
+// dockerLocalGet serves manifest / blob / tags-list reads for a local repo.
+func (h *ProxyHandler) dockerLocalGet(w http.ResponseWriter, r *http.Request, remote *models.Remote, head bool) {
+	req, ok := parseDockerPath(chi.URLParam(r, "*"))
+	if !ok {
+		dockerError(w, http.StatusNotFound, "NAME_UNKNOWN", "unrecognised registry path")
+		return
+	}
+	switch req.kind {
+	case "tags":
+		h.dockerTagsList(w, r, remote, req.image)
+	case "manifest":
+		h.dockerServeRef(w, r, remote, req.image+"/manifests/"+req.ref, head, true)
+	case "blob":
+		h.dockerServeRef(w, r, remote, req.image+"/blobs/"+req.ref, head, false)
+	default:
+		dockerError(w, http.StatusNotFound, "NAME_UNKNOWN", "unrecognised registry path")
+	}
+}
+
+// dockerServeRef streams the blob backing a local_files path. isManifest
+// controls only the default content type; the stored blob content type wins.
+func (h *ProxyHandler) dockerServeRef(w http.ResponseWriter, r *http.Request, remote *models.Remote, filePath string, head, isManifest bool) {
+	file, err := h.db.GetLocalFile(r.Context(), remote.Name, filePath)
+	if err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	if file == nil {
+		code := "BLOB_UNKNOWN"
+		if isManifest {
+			code = "MANIFEST_UNKNOWN"
+		}
+		dockerError(w, http.StatusNotFound, code, "not found")
+		return
+	}
+
+	s3Key := storage.BlobKey(file.ContentHash[len("sha256:"):])
+	reader, info, err := h.store.Download(r.Context(), s3Key)
+	if err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	defer reader.Close()
+
+	contentType := info.ContentType
+	if contentType == "" {
+		if isManifest {
+			contentType = "application/vnd.docker.distribution.manifest.v2+json"
+		} else {
+			contentType = "application/octet-stream"
+		}
+	}
+	w.Header().Set("Content-Type", contentType)
+	w.Header().Set("Content-Length", fmt.Sprintf("%d", info.Size))
+	w.Header().Set("Docker-Content-Digest", file.ContentHash)
+	w.Header().Set("Docker-Distribution-Api-Version", dockerAPIVersionHeader)
+	w.Header().Set("X-Artifact-Source", "local")
+	if head {
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+	w.WriteHeader(http.StatusOK)
+	io.Copy(w, reader)
+}
+
+func (h *ProxyHandler) dockerTagsList(w http.ResponseWriter, r *http.Request, remote *models.Remote, image string) {
+	prefix := image + "/manifests/"
+	files, err := h.db.ListLocalFilesByPrefix(r.Context(), remote.Name, prefix)
+	if err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	tags := []string{}
+	for _, f := range files {
+		ref := strings.TrimPrefix(f.FilePath, prefix)
+		if ref == "" || isDigest(ref) {
+			continue
+		}
+		tags = append(tags, ref)
+	}
+	sort.Strings(tags)
+	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Docker-Distribution-Api-Version", dockerAPIVersionHeader)
+	w.WriteHeader(http.StatusOK)
+	fmt.Fprintf(w, `{"name":%q,"tags":`, remote.Name+"/"+image)
+	writeJSONStringList(w, tags)
+	fmt.Fprint(w, "}")
+}
+
+func writeJSONStringList(w io.Writer, items []string) {
+	fmt.Fprint(w, "[")
+	for i, s := range items {
+		if i > 0 {
+			fmt.Fprint(w, ",")
+		}
+		fmt.Fprintf(w, "%q", s)
+	}
+	fmt.Fprint(w, "]")
+}
+
+// dockerStartUpload begins a blob upload. It honours a monolithic
+// POST?digest=... (blob in the POST body) and otherwise opens a chunked
+// session, returning its Location for the client's PATCH/PUT.
+func (h *ProxyHandler) dockerStartUpload(w http.ResponseWriter, r *http.Request, remote *models.Remote) {
+	req, ok := parseDockerPath(chi.URLParam(r, "*"))
+	if !ok || req.kind != "upload" {
+		dockerError(w, http.StatusNotFound, "NAME_UNKNOWN", "unrecognised registry path")
+		return
+	}
+
+	if digest := r.URL.Query().Get("digest"); digest != "" {
+		h.dockerCommitBlob(w, r, remote, req.image, digest, r.Body)
+		return
+	}
+
+	// Stage an empty object keyed by the upload UUID; PATCH/PUT append to it.
+	id := uuid.NewString()
+	if err := h.store.Upload(r.Context(), uploadKey(id), bytes.NewReader(nil), 0, "application/octet-stream"); err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	loc := fmt.Sprintf("/v2/%s/%s/blobs/uploads/%s", remote.Name, req.image, id)
+	w.Header().Set("Location", loc)
+	w.Header().Set("Docker-Upload-UUID", id)
+	w.Header().Set("Range", "0-0")
+	w.Header().Set("Docker-Distribution-Api-Version", dockerAPIVersionHeader)
+	w.WriteHeader(http.StatusAccepted)
+}
+
+func (h *ProxyHandler) dockerPatchUpload(w http.ResponseWriter, r *http.Request, remote *models.Remote) {
+	req, ok := parseDockerPath(chi.URLParam(r, "*"))
+	if !ok || req.kind != "upload" || req.ref == "" {
+		dockerError(w, http.StatusNotFound, "BLOB_UPLOAD_UNKNOWN", "unknown upload")
+		return
+	}
+	size, err := h.appendUpload(r.Context(), req.ref, r.Body)
+	if err != nil {
+		if errors.Is(err, errUploadUnknown) {
+			dockerError(w, http.StatusNotFound, "BLOB_UPLOAD_UNKNOWN", "unknown upload")
+			return
+		}
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	loc := fmt.Sprintf("/v2/%s/%s/blobs/uploads/%s", remote.Name, req.image, req.ref)
+	w.Header().Set("Location", loc)
+	w.Header().Set("Docker-Upload-UUID", req.ref)
+	w.Header().Set("Range", fmt.Sprintf("0-%d", size-1))
+	w.Header().Set("Docker-Distribution-Api-Version", dockerAPIVersionHeader)
+	w.WriteHeader(http.StatusAccepted)
+}
+
+// dockerFinishUpload completes a chunked upload: appends any final PUT body,
+// stores the assembled blob, and verifies its digest.
+func (h *ProxyHandler) dockerFinishUpload(w http.ResponseWriter, r *http.Request, remote *models.Remote, req dockerReq) {
+	digest := r.URL.Query().Get("digest")
+	if digest == "" {
+		dockerError(w, http.StatusBadRequest, "DIGEST_INVALID", "digest query parameter required")
+		return
+	}
+	if req.ref == "" {
+		// Monolithic PUT with no prior session: body is the whole blob.
+		h.dockerCommitBlob(w, r, remote, req.image, digest, r.Body)
+		return
+	}
+
+	key := uploadKey(req.ref)
+	reader, _, err := h.store.Download(r.Context(), key)
+	if err != nil {
+		dockerError(w, http.StatusNotFound, "BLOB_UPLOAD_UNKNOWN", "unknown upload")
+		return
+	}
+	defer reader.Close()
+	// Drop the staging object once we're done, regardless of outcome; a fresh
+	// context so cleanup still runs if the client disconnects.
+	defer h.store.Delete(context.Background(), key)
+
+	// Stream the staged bytes plus any trailing PUT body through the CAS in one
+	// pass — no extra round trip to re-assemble.
+	combined := io.MultiReader(reader, r.Body)
+	h.dockerCommitBlob(w, r, remote, req.image, digest, combined)
+}
+
+// dockerCommitBlob stores blob bytes through the CAS, verifies the client's
+// declared digest, and records the per-image local_files reference.
+func (h *ProxyHandler) dockerCommitBlob(w http.ResponseWriter, r *http.Request, remote *models.Remote, image, digest string, body io.Reader) {
+	result, err := h.cas.Store(r.Context(), body, "application/octet-stream")
+	if err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", fmt.Sprintf("store failed: %v", err))
+		return
+	}
+	if result.ContentHash != digest {
+		dockerError(w, http.StatusBadRequest, "DIGEST_INVALID", fmt.Sprintf("digest mismatch: got %s, declared %s", result.ContentHash, digest))
+		return
+	}
+	if err := h.db.UpsertBlob(r.Context(), result.ContentHash, result.S3Key, result.SizeBytes, "application/octet-stream"); err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	if err := h.db.CreateLocalFile(r.Context(), remote.Name, image+"/blobs/"+digest, result.ContentHash); err != nil && !errors.Is(err, database.ErrAlreadyExists) {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	w.Header().Set("Location", fmt.Sprintf("/v2/%s/%s/blobs/%s", remote.Name, image, digest))
+	w.Header().Set("Docker-Content-Digest", digest)
+	w.Header().Set("Docker-Distribution-Api-Version", dockerAPIVersionHeader)
+	w.WriteHeader(http.StatusCreated)
+}
+
+// dockerPutManifest stores a manifest and points its reference (tag or digest)
+// at it. Tags are mutable so a re-push moves the tag; digests are immutable.
+func (h *ProxyHandler) dockerPutManifest(w http.ResponseWriter, r *http.Request, remote *models.Remote, req dockerReq) {
+	body, err := io.ReadAll(r.Body)
+	if err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	contentType := r.Header.Get("Content-Type")
+	if contentType == "" {
+		contentType = "application/vnd.docker.distribution.manifest.v2+json"
+	}
+	sum := sha256.Sum256(body)
+	digest := "sha256:" + hex.EncodeToString(sum[:])
+
+	result, err := h.cas.Store(r.Context(), strings.NewReader(string(body)), contentType)
+	if err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", fmt.Sprintf("store failed: %v", err))
+		return
+	}
+	if err := h.db.UpsertBlob(r.Context(), result.ContentHash, result.S3Key, result.SizeBytes, contentType); err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	// Always addressable by digest (immutable).
+	if err := h.db.CreateLocalFile(r.Context(), remote.Name, req.image+"/manifests/"+digest, result.ContentHash); err != nil && !errors.Is(err, database.ErrAlreadyExists) {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	// If pushed under a tag, (re)point the tag at this manifest.
+	if !isDigest(req.ref) {
+		if err := h.db.UpsertLocalFile(r.Context(), remote.Name, req.image+"/manifests/"+req.ref, result.ContentHash); err != nil {
+			dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+			return
+		}
+	}
+
+	slog.Info("local docker manifest pushed", "repo", remote.Name, "image", req.image, "ref", req.ref, "digest", digest)
+	w.Header().Set("Location", fmt.Sprintf("/v2/%s/%s/manifests/%s", remote.Name, req.image, req.ref))
+	w.Header().Set("Docker-Content-Digest", digest)
+	w.Header().Set("Docker-Distribution-Api-Version", dockerAPIVersionHeader)
+	w.WriteHeader(http.StatusCreated)
+}

internal/api/v1/docker_test.go

@@ -0,0 +1,50 @@
+package v1
+
+import "testing"
+
+func TestParseDockerPath(t *testing.T) {
+	tests := []struct {
+		name      string
+		rest      string
+		wantOK    bool
+		wantImage string
+		wantKind  string
+		wantRef   string
+	}{
+		{"start upload trailing slash", "team/app/blobs/uploads/", true, "team/app", "upload", ""},
+		{"start upload no slash", "team/app/blobs/uploads", true, "team/app", "upload", ""},
+		{"patch upload with uuid", "team/app/blobs/uploads/abc-123", true, "team/app", "upload", "abc-123"},
+		{"single-segment image upload", "app/blobs/uploads/", true, "app", "upload", ""},
+		{"blob by digest", "team/app/blobs/sha256:deadbeef", true, "team/app", "blob", "sha256:deadbeef"},
+		{"manifest by tag", "team/app/manifests/v1.0.0", true, "team/app", "manifest", "v1.0.0"},
+		{"manifest by digest", "team/app/manifests/sha256:cafe", true, "team/app", "manifest", "sha256:cafe"},
+		{"tags list", "team/app/tags/list", true, "team/app", "tags", ""},
+		{"leading slash tolerated", "/team/app/manifests/latest", true, "team/app", "manifest", "latest"},
+		{"deep image name", "a/b/c/manifests/latest", true, "a/b/c", "manifest", "latest"},
+		{"unrecognised", "team/app/whatever", false, "", "", ""},
+		{"tags list without image", "tags/list", false, "", "", ""},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got, ok := parseDockerPath(tc.rest)
+			if ok != tc.wantOK {
+				t.Fatalf("ok = %v, want %v", ok, tc.wantOK)
+			}
+			if !tc.wantOK {
+				return
+			}
+			if got.image != tc.wantImage || got.kind != tc.wantKind || got.ref != tc.wantRef {
+				t.Fatalf("got %+v, want image=%q kind=%q ref=%q", got, tc.wantImage, tc.wantKind, tc.wantRef)
+			}
+		})
+	}
+}
+
+func TestIsDigest(t *testing.T) {
+	if !isDigest("sha256:abc") {
+		t.Fatal("sha256: prefix should be a digest")
+	}
+	if isDigest("v1.0.0") {
+		t.Fatal("a tag is not a digest")
+	}
+}

internal/api/v1/proxy.go

@@ -23,10 +23,18 @@ type ProxyHandler struct {
 	db            *database.DB
 	store         *storage.S3
 	local         *v2.LocalHandler
+	cas           *storage.CAS
 }
 
 func NewProxyHandler(engine *proxy.Engine, virtualEngine *virtual.Engine, db *database.DB, store *storage.S3, local *v2.LocalHandler) *ProxyHandler {
-	return &ProxyHandler{engine: engine, virtualEngine: virtualEngine, db: db, store: store, local: local}
+	return &ProxyHandler{
+		engine:        engine,
+		virtualEngine: virtualEngine,
+		db:            db,
+		store:         store,
+		local:         local,
+		cas:           storage.NewCAS(store),
+	}
 }
 
 func (h *ProxyHandler) Routes() chi.Router {
@@ -37,12 +45,20 @@ func (h *ProxyHandler) Routes() chi.Router {
 	return r
 }
 
+// DockerV2Routes mounts the Docker Registry HTTP API V2. Reads (GET/HEAD)
+// dispatch to a local registry implementation for local docker repos and fall
+// through to the upstream proxy otherwise; writes (POST/PATCH/PUT/DELETE) are
+// only valid for local docker repos and drive push.
 func (h *ProxyHandler) DockerV2Routes() chi.Router {
 	r := chi.NewRouter()
 	r.Get("/", h.handleDockerPing)
 	r.Head("/", h.handleDockerPing)
-	r.Get("/{remoteName}/*", h.handleProxy)
-	r.Head("/{remoteName}/*", h.handleProxy)
+	r.Get("/{remoteName}/*", h.dockerGet)
+	r.Head("/{remoteName}/*", h.dockerHead)
+	r.Post("/{remoteName}/*", h.dockerPost)
+	r.Patch("/{remoteName}/*", h.dockerPatch)
+	r.Put("/{remoteName}/*", h.dockerPut)
+	r.Delete("/{remoteName}/*", h.dockerDelete)
 	return r
 }
 
@@ -67,7 +83,16 @@ func (h *ProxyHandler) handleProxy(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	result, err := h.engine.Fetch(r.Context(), *remote, path, prov)
+	// Metadata-only remotes (e.g. github_rpm) synthesize their own responses and
+	// redirect package downloads to a backend remote instead of proxying bytes.
+	if rs, ok := prov.(provider.RemoteServer); ok {
+		proxyBaseURL := fmt.Sprintf("%s://%s", scheme(r), r.Host)
+		if rs.ServeRemote(w, r, *remote, path, proxyBaseURL, h.db) {
+			return
+		}
+	}
+
+	result, err := h.engine.Fetch(r.Context(), *remote, path, prov, r.Header)
 	if err != nil {
 		var proxyErr *proxy.ProxyError
 		if errors.As(err, &proxyErr) {
@@ -89,6 +114,42 @@ func (h *ProxyHandler) handleProxy(w http.ResponseWriter, r *http.Request) {
 	io.Copy(w, result.Reader)
 }
 
+func (h *ProxyHandler) handleProxyHead(w http.ResponseWriter, r *http.Request) {
+	remoteName := chi.URLParam(r, "remoteName")
+	path := chi.URLParam(r, "*")
+
+	remote, err := h.db.GetRemote(r.Context(), remoteName)
+	if err != nil {
+		http.Error(w, fmt.Sprintf("remote %q not found", remoteName), http.StatusNotFound)
+		return
+	}
+
+	prov, err := provider.Get(remote.PackageType)
+	if err != nil {
+		http.Error(w, fmt.Sprintf("no provider for %q", remote.PackageType), http.StatusInternalServerError)
+		return
+	}
+
+	result, err := h.engine.Head(r.Context(), *remote, path, prov)
+	if err != nil {
+		var proxyErr *proxy.ProxyError
+		if errors.As(err, &proxyErr) {
+			http.Error(w, proxyErr.Message, proxyErr.Status)
+			return
+		}
+		slog.Error("proxy head failed", "remote", remoteName, "path", path, "error", err)
+		http.Error(w, "bad gateway", http.StatusBadGateway)
+		return
+	}
+
+	w.Header().Set("Content-Type", result.ContentType)
+	w.Header().Set("X-Artifact-Source", result.Source)
+	if result.Size > 0 {
+		w.Header().Set("Content-Length", fmt.Sprintf("%d", result.Size))
+	}
+	w.WriteHeader(http.StatusOK)
+}
+
 func (h *ProxyHandler) handleVirtual(w http.ResponseWriter, r *http.Request) {
 	virtualName := chi.URLParam(r, "virtualName")
 	path := chi.URLParam(r, "*")

internal/api/v1/scheme_test.go

@@ -0,0 +1,20 @@
+package v1
+
+import (
+	"crypto/tls"
+	"net/http"
+	"testing"
+)
+
+func TestScheme(t *testing.T) {
+	if got := scheme(&http.Request{TLS: &tls.ConnectionState{}}); got != "https" {
+		t.Errorf("TLS request scheme = %q, want https", got)
+	}
+	r := &http.Request{Header: http.Header{"X-Forwarded-Proto": {"https"}}}
+	if got := scheme(r); got != "https" {
+		t.Errorf("X-Forwarded-Proto scheme = %q, want https", got)
+	}
+	if got := scheme(&http.Request{Header: http.Header{}}); got != "http" {
+		t.Errorf("default scheme = %q, want http", got)
+	}
+}

internal/api/v2/errorpaths_test.go

@@ -0,0 +1,130 @@
+package v2
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"strings"
+	"testing"
+
+	"git.unkin.net/unkin/artifactapi/internal/database"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+)
+
+var testDSN string
+
+func TestMain(m *testing.M) {
+	ctx := context.Background()
+	dsn, terminate, err := testsupport.StartPostgres(ctx)
+	if err != nil {
+		os.Exit(m.Run())
+	}
+	testDSN = dsn
+	code := m.Run()
+	terminate()
+	if code != 0 {
+		os.Exit(code)
+	}
+}
+
+// closedDB returns a DB whose pool has been closed, so every query fails —
+// used to drive the handlers' error branches.
+func closedDB(t *testing.T) *database.DB {
+	t.Helper()
+	if testDSN == "" {
+		t.Skip("Docker unavailable")
+	}
+	db, err := database.New(testDSN)
+	if err != nil {
+		t.Fatalf("new db: %v", err)
+	}
+	db.Close()
+	return db
+}
+
+func do(t *testing.T, h http.Handler, method, path, body string) int {
+	t.Helper()
+	var r io.Reader
+	if body != "" {
+		r = strings.NewReader(body)
+	}
+	req := httptest.NewRequest(method, path, r)
+	w := httptest.NewRecorder()
+	h.ServeHTTP(w, req)
+	return w.Code
+}
+
+func TestRemotesErrorPaths(t *testing.T) {
+	h := NewRemotesHandler(closedDB(t), nil, nil).Routes()
+	if c := do(t, h, "GET", "/", ""); c != 500 {
+		t.Errorf("list with dead db = %d, want 500", c)
+	}
+	if c := do(t, h, "POST", "/", `{"name":"x","package_type":"generic","repo_type":"remote","base_url":"https://x"}`); c != 500 {
+		t.Errorf("create with dead db = %d, want 500", c)
+	}
+	if c := do(t, h, "PUT", "/x", `{"package_type":"generic","base_url":"https://x"}`); c != 500 {
+		t.Errorf("update with dead db = %d, want 500", c)
+	}
+	if c := do(t, h, "GET", "/x", ""); c != 404 {
+		t.Errorf("get missing = %d, want 404", c)
+	}
+	if c := do(t, h, "DELETE", "/x", ""); c != 500 {
+		t.Errorf("delete with dead db = %d, want 500", c)
+	}
+	// Bad request bodies never reach the db.
+	if c := do(t, h, "POST", "/", `not json`); c != 400 {
+		t.Errorf("invalid json = %d, want 400", c)
+	}
+}
+
+func TestVirtualsErrorPaths(t *testing.T) {
+	h := NewVirtualsHandler(closedDB(t)).Routes()
+	if c := do(t, h, "GET", "/", ""); c != 500 {
+		t.Errorf("list = %d, want 500", c)
+	}
+	if c := do(t, h, "GET", "/x", ""); c != 404 {
+		t.Errorf("get missing = %d, want 404", c)
+	}
+	if c := do(t, h, "POST", "/", `{"name":"v","package_type":"helm","members":["a"]}`); c != 500 {
+		t.Errorf("create = %d, want 500", c)
+	}
+	if c := do(t, h, "PUT", "/v", `{"package_type":"helm","members":["a"]}`); c != 500 {
+		t.Errorf("update = %d, want 500", c)
+	}
+	if c := do(t, h, "DELETE", "/v", ""); c != 500 {
+		t.Errorf("delete = %d, want 500", c)
+	}
+}
+
+func TestStatsErrorPaths(t *testing.T) {
+	h := NewStatsHandler(closedDB(t)).Routes()
+	for _, p := range []string{"/", "/top-remotes", "/top-files-by-hits", "/top-files-by-bandwidth"} {
+		if c := do(t, h, "GET", p, ""); c != 500 {
+			t.Errorf("stats %s = %d, want 500", p, c)
+		}
+	}
+}
+
+func TestLocalErrorPaths(t *testing.T) {
+	h := NewLocalHandler(closedDB(t), nil).Routes()
+	// GetRemote fails on the closed db -> not found.
+	if c := do(t, h, "PUT", "/x/files/a.bin", "data"); c != 404 {
+		t.Errorf("upload unknown repo = %d, want 404", c)
+	}
+	// download / remove hit the db and 500.
+	if c := do(t, h, "GET", "/x/files/a.bin", ""); c != 500 {
+		t.Errorf("download = %d, want 500", c)
+	}
+	if c := do(t, h, "DELETE", "/x/files/a.bin", ""); c != 500 {
+		t.Errorf("remove = %d, want 500", c)
+	}
+}
+
+func TestLocalHandlerDBAccessor(t *testing.T) {
+	db := closedDB(t)
+	if NewLocalHandler(db, nil).DB() != db {
+		t.Error("DB() should return the handler's database")
+	}
+}

internal/api/v2/local.go

@@ -185,13 +185,35 @@ func (h *LocalHandler) remove(w http.ResponseWriter, r *http.Request) {
 	repoName := chi.URLParam(r, "name")
 	filePath := chi.URLParam(r, "*")
 
-	if err := h.db.DeleteLocalFile(r.Context(), repoName, filePath); err != nil {
+	if err := deleteLocalFile(r.Context(), h.db, repoName, filePath); err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
 	w.WriteHeader(http.StatusNoContent)
 }
 
+// deleteLocalFile removes a local file and runs the provider's post-delete hook,
+// so provider-derived state (e.g. RPM metadata that feeds generated repodata)
+// stops referencing a package that no longer exists.
+func deleteLocalFile(ctx context.Context, db *database.DB, repoName, filePath string) error {
+	if err := db.DeleteLocalFile(ctx, repoName, filePath); err != nil {
+		return err
+	}
+
+	remote, err := db.GetRemote(ctx, repoName)
+	if err != nil {
+		return nil // file is gone; no repo left to resolve a cleanup hook from
+	}
+	prov, err := provider.Get(remote.PackageType)
+	if err != nil {
+		return nil
+	}
+	if hook, ok := prov.(provider.PostDeleteHook); ok {
+		return hook.AfterDelete(ctx, repoName, filePath, db)
+	}
+	return nil
+}
+
 func (h *LocalHandler) DB() *database.DB {
 	return h.db
 }

internal/api/v2/local_evict_cleanup_test.go

@@ -0,0 +1,75 @@
+package v2
+
+import (
+	"context"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/go-chi/chi/v5"
+
+	"git.unkin.net/unkin/artifactapi/internal/database"
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	_ "git.unkin.net/unkin/artifactapi/internal/provider/rpm" // register the rpm provider so its PostDeleteHook runs
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// TestLocalEvictCleansRPMMetadata verifies that evicting an RPM from a local
+// repo also removes the derived rpm_metadata row, so generated repodata stops
+// listing the deleted package.
+func TestLocalEvictCleansRPMMetadata(t *testing.T) {
+	if testDSN == "" {
+		t.Skip("Docker unavailable")
+	}
+	ctx := context.Background()
+	db, err := database.New(testDSN)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	const repo = "rpm-evict-cleanup"
+	if err := db.CreateRemote(ctx, &models.Remote{Name: repo, PackageType: models.PackageRPM, RepoType: models.RepoTypeLocal}); err != nil {
+		t.Fatal(err)
+	}
+
+	const hash = "sha256:bb22"
+	const path = "Packages/example-0.1.0-1.x86_64.rpm"
+	if err := db.UpsertBlob(ctx, hash, "blobs/bb/22", 2048, "application/x-rpm"); err != nil {
+		t.Fatal(err)
+	}
+	if err := db.CreateLocalFile(ctx, repo, path, hash); err != nil {
+		t.Fatal(err)
+	}
+	if err := db.InsertRPMMetadata(ctx, &provider.RPMMetadata{
+		RepoName: repo, FilePath: path, ContentHash: hash,
+		Name: "example", Version: "0.1.0", Release: "1", Arch: "x86_64",
+		Requires: []provider.RPMDep{}, Provides: []provider.RPMDep{},
+		Files: []provider.RPMFile{}, Changelogs: []provider.RPMChangelog{},
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	h := NewObjectsHandler(db)
+	router := chi.NewRouter()
+	router.Route("/locals/{name}/objects", func(r chi.Router) {
+		r.Delete("/*", h.LocalRoutes().ServeHTTP)
+	})
+
+	del := httptest.NewRequest("DELETE", "/locals/"+repo+"/objects/"+path, nil)
+	dw := httptest.NewRecorder()
+	router.ServeHTTP(dw, del)
+	if dw.Code != 204 {
+		t.Fatalf("evict = %d, want 204", dw.Code)
+	}
+
+	if f, _ := db.GetLocalFile(ctx, repo, path); f != nil {
+		t.Fatalf("local file still present after evict: %+v", f)
+	}
+	entries, err := db.ListRPMMetadataEntries(ctx, repo)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(entries) != 0 {
+		t.Fatalf("rpm_metadata still present after evict: %+v", entries)
+	}
+}

internal/api/v2/local_fault_test.go

@@ -0,0 +1,88 @@
+package v2
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+
+	"git.unkin.net/unkin/artifactapi/internal/database"
+	"git.unkin.net/unkin/artifactapi/internal/storage"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// TestLocalUploadStoreFailure covers the upload handlers' store-error branches
+// by killing the object store after a successful upload.
+func TestLocalUploadStoreFailure(t *testing.T) {
+	if testDSN == "" {
+		t.Skip("Docker unavailable")
+	}
+	ctx := context.Background()
+	db, err := database.New(testDSN)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	conn, termMinio, err := testsupport.StartMinio(ctx)
+	if err != nil {
+		t.Skip("minio unavailable")
+	}
+	var store *storage.S3
+	for i := 0; i < 20; i++ {
+		if store, err = storage.NewS3(conn.Endpoint, conn.AccessKey, conn.SecretKey, "fault", false, ""); err == nil {
+			break
+		}
+		time.Sleep(500 * time.Millisecond)
+	}
+	if err != nil {
+		termMinio()
+		t.Fatal(err)
+	}
+
+	for _, pt := range []models.PackageType{models.PackageGeneric, models.PackagePyPI} {
+		if err := db.CreateRemote(ctx, &models.Remote{Name: "fault-" + string(pt), PackageType: pt, RepoType: models.RepoTypeLocal}); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	h := NewLocalHandler(db, store)
+	router := chi.NewRouter()
+	router.Route("/remotes/{name}/files", func(r chi.Router) {
+		r.Put("/*", h.Routes().ServeHTTP)
+	})
+	srv := httptest.NewServer(router)
+	defer srv.Close()
+
+	put := func(name, path, body string) int {
+		rq, _ := http.NewRequest("PUT", srv.URL+"/remotes/"+name+"/files/"+path, strings.NewReader(body))
+		resp, err := http.DefaultClient.Do(rq)
+		if err != nil {
+			t.Fatalf("put: %v", err)
+		}
+		resp.Body.Close()
+		return resp.StatusCode
+	}
+
+	// Sanity: uploads succeed while the store is up.
+	if c := put("fault-generic", "ok.bin", "data"); c != 201 {
+		t.Fatalf("generic upload while up = %d", c)
+	}
+	if c := put("fault-pypi", "foo-1.0-py3-none-any.whl", "wheel"); c != 201 {
+		t.Fatalf("pypi upload while up = %d", c)
+	}
+
+	// Kill the store; subsequent CAS.Store calls fail -> 500.
+	termMinio()
+	if c := put("fault-generic", "after.bin", "data"); c != 500 {
+		t.Errorf("generic upload after store down = %d, want 500", c)
+	}
+	if c := put("fault-pypi", "bar-1.0-py3-none-any.whl", "wheel"); c != 500 {
+		t.Errorf("pypi upload after store down = %d, want 500", c)
+	}
+}

internal/api/v2/local_objects_test.go

@@ -0,0 +1,78 @@
+package v2
+
+import (
+	"context"
+	"encoding/json"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/go-chi/chi/v5"
+
+	"git.unkin.net/unkin/artifactapi/internal/database"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// TestLocalObjectsListing verifies that files uploaded to a local repo (which
+// live in local_files, not artifacts) are listed by the local objects endpoint
+// and can be evicted through it.
+func TestLocalObjectsListing(t *testing.T) {
+	if testDSN == "" {
+		t.Skip("Docker unavailable")
+	}
+	ctx := context.Background()
+	db, err := database.New(testDSN)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	const repo = "rpm-local-objs"
+	if err := db.CreateRemote(ctx, &models.Remote{Name: repo, PackageType: models.PackageRPM, RepoType: models.RepoTypeLocal}); err != nil {
+		t.Fatal(err)
+	}
+
+	const hash = "sha256:aa11"
+	const path = "Packages/example-0.1.0-1.x86_64.rpm"
+	if err := db.UpsertBlob(ctx, hash, "blobs/aa/11", 1234, "application/x-rpm"); err != nil {
+		t.Fatal(err)
+	}
+	if err := db.CreateLocalFile(ctx, repo, path, hash); err != nil {
+		t.Fatal(err)
+	}
+
+	h := NewObjectsHandler(db)
+	router := chi.NewRouter()
+	router.Route("/locals/{name}/objects", func(r chi.Router) {
+		r.Get("/", h.LocalRoutes().ServeHTTP)
+		r.Delete("/*", h.LocalRoutes().ServeHTTP)
+	})
+
+	// The uploaded package must appear in the listing with its blob size.
+	req := httptest.NewRequest("GET", "/locals/"+repo+"/objects", nil)
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+	if w.Code != 200 {
+		t.Fatalf("list = %d, want 200", w.Code)
+	}
+	var got []models.Artifact
+	if err := json.Unmarshal(w.Body.Bytes(), &got); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if len(got) != 1 {
+		t.Fatalf("got %d objects, want 1", len(got))
+	}
+	if got[0].Path != path || got[0].SizeBytes != 1234 || got[0].ContentHash != hash {
+		t.Fatalf("unexpected object: %+v", got[0])
+	}
+
+	// Eviction removes it from local_files.
+	del := httptest.NewRequest("DELETE", "/locals/"+repo+"/objects/"+path, nil)
+	dw := httptest.NewRecorder()
+	router.ServeHTTP(dw, del)
+	if dw.Code != 204 {
+		t.Fatalf("evict = %d, want 204", dw.Code)
+	}
+	if f, _ := db.GetLocalFile(ctx, repo, path); f != nil {
+		t.Fatalf("file still present after evict: %+v", f)
+	}
+}

internal/api/v2/objects.go

@@ -25,9 +25,18 @@ func (h *ObjectsHandler) Routes() chi.Router {
 	return r
 }
 
-func (h *ObjectsHandler) list(w http.ResponseWriter, r *http.Request) {
-	remoteName := chi.URLParam(r, "name")
-	limit, _ := strconv.Atoi(r.URL.Query().Get("per_page"))
+// LocalRoutes lists and evicts objects for local repos, which live in the
+// local_files table rather than the artifacts table used by remotes.
+func (h *ObjectsHandler) LocalRoutes() chi.Router {
+	r := chi.NewRouter()
+	r.Get("/", h.listLocal)
+	r.Delete("/*", h.evictLocal)
+	return r
+}
+
+// pageBounds parses the shared page/per_page query params into a SQL limit and offset.
+func pageBounds(r *http.Request) (limit, offset int) {
+	limit, _ = strconv.Atoi(r.URL.Query().Get("per_page"))
 	if limit <= 0 || limit > 5000 {
 		limit = 50
 	}
@@ -35,7 +44,12 @@ func (h *ObjectsHandler) list(w http.ResponseWriter, r *http.Request) {
 	if page <= 0 {
 		page = 1
 	}
-	offset := (page - 1) * limit
+	return limit, (page - 1) * limit
+}
+
+func (h *ObjectsHandler) list(w http.ResponseWriter, r *http.Request) {
+	remoteName := chi.URLParam(r, "name")
+	limit, offset := pageBounds(r)
 
 	artifacts, err := h.db.ListArtifacts(r.Context(), remoteName, limit, offset)
 	if err != nil {
@@ -45,6 +59,29 @@ func (h *ObjectsHandler) list(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, artifacts)
 }
 
+func (h *ObjectsHandler) listLocal(w http.ResponseWriter, r *http.Request) {
+	repoName := chi.URLParam(r, "name")
+	limit, offset := pageBounds(r)
+
+	artifacts, err := h.db.ListLocalArtifacts(r.Context(), repoName, limit, offset)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, http.StatusOK, artifacts)
+}
+
+func (h *ObjectsHandler) evictLocal(w http.ResponseWriter, r *http.Request) {
+	repoName := chi.URLParam(r, "name")
+	path := chi.URLParam(r, "*")
+
+	if err := deleteLocalFile(r.Context(), h.db, repoName, path); err != nil {
+		http.Error(w, fmt.Sprintf("evict failed: %v", err), http.StatusInternalServerError)
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
 func (h *ObjectsHandler) evict(w http.ResponseWriter, r *http.Request) {
 	remoteName := chi.URLParam(r, "name")
 	path := chi.URLParam(r, "*")

internal/api/v2/remotes.go

@@ -1,8 +1,10 @@
 package v2
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
+	"log/slog"
 	"net/http"
 
 	"github.com/go-chi/chi/v5"
@@ -11,12 +13,29 @@ import (
 	"git.unkin.net/unkin/artifactapi/pkg/models"
 )
 
-type RemotesHandler struct {
-	db *database.DB
+// Primer enqueues a background metadata prime for a newly created remote so the
+// create call never blocks on a derive. *rpm.Syncer and *deb.Syncer satisfy it.
+type Primer interface {
+	EnqueuePrime(remote models.Remote)
 }
 
-func NewRemotesHandler(db *database.DB) *RemotesHandler {
-	return &RemotesHandler{db: db}
+// MetadataFlusher purges a remote's cached mutable metadata (repodata / Release
+// / APKINDEX freshness keys). *cache.Redis satisfies it.
+type MetadataFlusher interface {
+	FlushRemote(ctx context.Context, remote string) error
+}
+
+type RemotesHandler struct {
+	db      *database.DB
+	cache   MetadataFlusher
+	primers map[models.PackageType]Primer
+}
+
+// NewRemotesHandler wires the handler to the metadata cache and per-type
+// primers. cache may be nil (flush-on-backend-change is skipped); primers may
+// be nil (a package type with no registered primer simply skips priming).
+func NewRemotesHandler(db *database.DB, cache MetadataFlusher, primers map[models.PackageType]Primer) *RemotesHandler {
+	return &RemotesHandler{db: db, cache: cache, primers: primers}
 }
 
 func (h *RemotesHandler) Routes() chi.Router {
@@ -69,10 +88,27 @@ func (h *RemotesHandler) create(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "base_url is required for remote repositories", http.StatusBadRequest)
 		return
 	}
+	if err := remote.ValidateMirrorlist(); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	if err := remote.ValidateMirrorStrategy(); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	if err := remote.ValidatePatterns(); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
 	if err := h.db.CreateRemote(r.Context(), &remote); err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
+	// Prime a metadata-only remote (github_rpm/github_deb) in the background so
+	// its first index request is served from cache instead of a cold derive.
+	if primer := h.primers[remote.PackageType]; primer != nil {
+		primer.EnqueuePrime(remote)
+	}
 	writeJSON(w, http.StatusCreated, remote)
 }
 
@@ -84,10 +120,42 @@ func (h *RemotesHandler) update(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	remote.Name = name
+	if err := remote.ValidateMirrorlist(); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	if err := remote.ValidateMirrorStrategy(); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	if err := remote.ValidatePatterns(); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	// Capture the current backend before the update so we can tell whether the
+	// remote's base_url (its upstream) changed. A read failure just means we
+	// skip the freshness flush; it must not block the update.
+	oldBaseURL, oldKnown := "", false
+	if existing, err := h.db.GetRemote(r.Context(), name); err == nil {
+		oldBaseURL, oldKnown = existing.BaseURL, true
+	}
 	if err := h.db.UpdateRemote(r.Context(), &remote); err != nil {
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
 	}
+	// Changing the backend invalidates any cached mutable metadata (repodata /
+	// Release / APKINDEX): purge it so the next request re-fetches from the new
+	// upstream instead of serving stale data until TTL expiry. A flush failure
+	// is logged but does not fail the request — the DB update already landed.
+	if oldKnown && oldBaseURL != remote.BaseURL && h.cache != nil {
+		if err := h.cache.FlushRemote(r.Context(), name); err != nil {
+			slog.Warn("flush cached metadata after base_url change failed",
+				"remote", name, "error", err)
+		} else {
+			slog.Info("flushed cached metadata after base_url change",
+				"remote", name, "old_base_url", oldBaseURL, "new_base_url", remote.BaseURL)
+		}
+	}
 	writeJSON(w, http.StatusOK, remote)
 }
 

internal/api/v2/remotes_flush_test.go

@@ -0,0 +1,96 @@
+package v2
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"git.unkin.net/unkin/artifactapi/internal/database"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// fakeFlusher records FlushRemote calls so a test can assert whether — and how
+// often — a remote's cached metadata was purged.
+type fakeFlusher struct {
+	calls []string
+	err   error
+}
+
+func (f *fakeFlusher) FlushRemote(_ context.Context, remote string) error {
+	f.calls = append(f.calls, remote)
+	return f.err
+}
+
+func seedRemote(t *testing.T, db *database.DB, name, baseURL string) {
+	t.Helper()
+	err := db.CreateRemote(context.Background(), &models.Remote{
+		Name:        name,
+		PackageType: models.PackageRPM,
+		RepoType:    models.RepoTypeRemote,
+		BaseURL:     baseURL,
+	})
+	if err != nil {
+		t.Fatalf("seed remote: %v", err)
+	}
+}
+
+// A base_url change must flush the remote's cached metadata exactly once, while
+// an update that leaves base_url untouched must not flush at all.
+func TestUpdateFlushesCacheOnBaseURLChange(t *testing.T) {
+	if testDSN == "" {
+		t.Skip("Docker unavailable")
+	}
+	db, err := database.New(testDSN)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	const name = "rpm-flush-change"
+	seedRemote(t, db, name, "https://old.example.com/repo")
+
+	ff := &fakeFlusher{}
+	h := NewRemotesHandler(db, ff, nil).Routes()
+
+	if c := do(t, h, "PUT", "/"+name, `{"package_type":"rpm","repo_type":"remote","base_url":"https://new.example.com/repo"}`); c != 200 {
+		t.Fatalf("update (backend change) = %d, want 200", c)
+	}
+	if len(ff.calls) != 1 || ff.calls[0] != name {
+		t.Fatalf("flush calls = %v, want exactly one flush of %q", ff.calls, name)
+	}
+
+	// Re-updating with the same (now current) base_url must not flush again.
+	ff.calls = nil
+	if c := do(t, h, "PUT", "/"+name, `{"package_type":"rpm","repo_type":"remote","base_url":"https://new.example.com/repo"}`); c != 200 {
+		t.Fatalf("update (no backend change) = %d, want 200", c)
+	}
+	if len(ff.calls) != 0 {
+		t.Fatalf("flush calls = %v, want no flush when base_url is unchanged", ff.calls)
+	}
+}
+
+// A flush error must be swallowed: the DB update already succeeded, so the
+// request still returns 200.
+func TestUpdateFlushFailureStillSucceeds(t *testing.T) {
+	if testDSN == "" {
+		t.Skip("Docker unavailable")
+	}
+	db, err := database.New(testDSN)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	const name = "rpm-flush-error"
+	seedRemote(t, db, name, "https://old.example.com/repo")
+
+	ff := &fakeFlusher{err: errors.New("redis down")}
+	h := NewRemotesHandler(db, ff, nil).Routes()
+
+	if c := do(t, h, "PUT", "/"+name, `{"package_type":"rpm","repo_type":"remote","base_url":"https://new.example.com/repo"}`); c != 200 {
+		t.Fatalf("update with failing flush = %d, want 200", c)
+	}
+	if len(ff.calls) != 1 {
+		t.Fatalf("flush calls = %v, want exactly one attempted flush", ff.calls)
+	}
+}

internal/auth/basic_test.go

@@ -0,0 +1,23 @@
+package auth
+
+import (
+	"encoding/base64"
+	"testing"
+
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+func TestBasicHeaders(t *testing.T) {
+	h := BasicHeaders(models.Remote{Username: "alice", Password: "secret"})
+	got := h.Get("Authorization")
+	want := "Basic " + base64.StdEncoding.EncodeToString([]byte("alice:secret"))
+	if got != want {
+		t.Errorf("Authorization = %q, want %q", got, want)
+	}
+}
+
+func TestBasicHeadersNoUser(t *testing.T) {
+	if h := BasicHeaders(models.Remote{}); h.Get("Authorization") != "" {
+		t.Error("expected no Authorization header without a username")
+	}
+}

internal/cache/cache_test.go

@@ -0,0 +1,133 @@
+package cache
+
+import (
+	"context"
+	"os"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+)
+
+var testRedis *Redis
+
+func TestMain(m *testing.M) {
+	ctx := context.Background()
+	url, terminate, err := testsupport.StartRedis(ctx)
+	if err != nil {
+		os.Exit(m.Run())
+	}
+	r, err := NewRedis(url)
+	if err != nil {
+		terminate()
+		panic(err)
+	}
+	testRedis = r
+	code := m.Run()
+	r.Close()
+	terminate()
+	if code != 0 {
+		os.Exit(code)
+	}
+}
+
+func requireRedis(t *testing.T) {
+	t.Helper()
+	if testRedis == nil {
+		t.Skip("Docker unavailable; skipping cache integration test")
+	}
+}
+
+func TestNewRedisInvalid(t *testing.T) {
+	if _, err := NewRedis("://bad-url"); err == nil {
+		t.Error("expected error for invalid redis URL")
+	}
+}
+
+func TestTTL(t *testing.T) {
+	requireRedis(t)
+	ctx := context.Background()
+	if fresh, _ := testRedis.CheckTTL(ctx, "r", "missing"); fresh {
+		t.Error("missing key should not be fresh")
+	}
+	if err := testRedis.SetTTL(ctx, "r", "p", time.Minute); err != nil {
+		t.Fatal(err)
+	}
+	if fresh, err := testRedis.CheckTTL(ctx, "r", "p"); err != nil || !fresh {
+		t.Errorf("expected fresh after SetTTL: %v %v", fresh, err)
+	}
+}
+
+func TestLock(t *testing.T) {
+	requireRedis(t)
+	ctx := context.Background()
+	ok, err := testRedis.AcquireLock(ctx, "r", "lockpath", time.Minute)
+	if err != nil || !ok {
+		t.Fatalf("first acquire should succeed: %v %v", ok, err)
+	}
+	if ok, _ := testRedis.AcquireLock(ctx, "r", "lockpath", time.Minute); ok {
+		t.Error("second acquire should fail while held")
+	}
+	if err := testRedis.ReleaseLock(ctx, "r", "lockpath"); err != nil {
+		t.Fatal(err)
+	}
+	if ok, _ := testRedis.AcquireLock(ctx, "r", "lockpath", time.Minute); !ok {
+		t.Error("acquire should succeed after release")
+	}
+}
+
+func TestETagAndToken(t *testing.T) {
+	requireRedis(t)
+	ctx := context.Background()
+	if v, _ := testRedis.GetETag(ctx, "r", "missing"); v != "" {
+		t.Error("missing etag should be empty")
+	}
+	testRedis.SetETag(ctx, "r", "p", `"abc"`, time.Minute)
+	if v, _ := testRedis.GetETag(ctx, "r", "p"); v != `"abc"` {
+		t.Errorf("etag = %q", v)
+	}
+
+	if v, _ := testRedis.GetToken(ctx, "missing"); v != "" {
+		t.Error("missing token should be empty")
+	}
+	testRedis.SetToken(ctx, "key", "tok", time.Minute)
+	if v, _ := testRedis.GetToken(ctx, "key"); v != "tok" {
+		t.Errorf("token = %q", v)
+	}
+}
+
+func TestCircuit(t *testing.T) {
+	requireRedis(t)
+	ctx := context.Background()
+	if n, _ := testRedis.GetCircuitFailures(ctx, "cr"); n != 0 {
+		t.Errorf("initial failures = %d", n)
+	}
+	n1, err := testRedis.IncrCircuitFailure(ctx, "cr", time.Minute)
+	if err != nil || n1 != 1 {
+		t.Fatalf("first incr = %d %v", n1, err)
+	}
+	n2, _ := testRedis.IncrCircuitFailure(ctx, "cr", time.Minute)
+	if n2 != 2 {
+		t.Errorf("second incr = %d", n2)
+	}
+	if n, _ := testRedis.GetCircuitFailures(ctx, "cr"); n != 2 {
+		t.Errorf("get failures = %d", n)
+	}
+	testRedis.ResetCircuit(ctx, "cr")
+	if n, _ := testRedis.GetCircuitFailures(ctx, "cr"); n != 0 {
+		t.Errorf("failures after reset = %d", n)
+	}
+}
+
+func TestFlushRemote(t *testing.T) {
+	requireRedis(t)
+	ctx := context.Background()
+	testRedis.SetTTL(ctx, "flushme", "a", time.Hour)
+	testRedis.SetETag(ctx, "flushme", "a", "x", time.Hour)
+	if err := testRedis.FlushRemote(ctx, "flushme"); err != nil {
+		t.Fatal(err)
+	}
+	if fresh, _ := testRedis.CheckTTL(ctx, "flushme", "a"); fresh {
+		t.Error("expected keys flushed")
+	}
+}

internal/cache/redis.go

@@ -70,6 +70,18 @@ func (r *Redis) GetETag(ctx context.Context, remote, path string) (string, error
 	return val, err
 }
 
+func (r *Redis) GetToken(ctx context.Context, key string) (string, error) {
+	val, err := r.client.Get(ctx, "token:"+key).Result()
+	if err == redis.Nil {
+		return "", nil
+	}
+	return val, err
+}
+
+func (r *Redis) SetToken(ctx context.Context, key, token string, ttl time.Duration) error {
+	return r.client.Set(ctx, "token:"+key, token, ttl).Err()
+}
+
 func (r *Redis) IncrCircuitFailure(ctx context.Context, remote string, cooldown time.Duration) (int64, error) {
 	key := fmt.Sprintf("circuit:%s", remote)
 	pipe := r.client.Pipeline()

internal/config/env.go

@@ -24,6 +24,38 @@ type Config struct {
 	S3Bucket    string
 	S3Secure    bool
 	S3Region    string
+
+	// Terraform provider registry signing. When TFSigningKeyPath points at a
+	// readable armored GPG private key, artifactapi serves local terraform
+	// repos as a real provider registry (service discovery + signed
+	// SHA256SUMS). Left empty, the registry endpoints stay disabled.
+	TFSigningKeyPath       string
+	TFSigningKeyPassphrase string
+	TFProviderProtocols    string
+
+	// github_rpm background syncer. The syncer keeps derived RPM metadata for
+	// every github_rpm remote fresh off the client request path, sharing a
+	// single global token-bucket limiter across all remotes so GitHub is never
+	// hammered. Defaults are conservative: 1 req/s (3600/hr) sits well under an
+	// authenticated token's 5000/hr. Unauthenticated remotes (60/hr) lean on
+	// ETag/304 — an unchanged repo costs nothing — so keep those repos small or
+	// configure a token.
+	GitHubSyncRatePerSec   float64
+	GitHubSyncBurst        int
+	GitHubSyncWorkers      int
+	GitHubSyncPollInterval int
+
+	// Server-level GitHub machine credential, applied by default to every
+	// outbound GitHub request (releases scan, ranged asset fetches, and the
+	// generic-github byte proxy for private assets). Delivered via env/secret
+	// only — never stored per-remote, never returned by an API, never logged.
+	// Configure exactly one mode: a Personal Access Token, or a GitHub App
+	// (id + installation id + private key). Partial App config fails at startup.
+	GitHubToken             string
+	GitHubAppID             string
+	GitHubAppInstallationID string
+	GitHubAppPrivateKey     string
+	GitHubAppPrivateKeyPath string
 }
 
 func (c *Config) DatabaseDSN() string {
@@ -41,6 +73,23 @@ func Load() (*Config, error) {
 
 	s3Secure, _ := strconv.ParseBool(getenv("MINIO_SECURE", "false"))
 
+	syncRate, err := strconv.ParseFloat(getenv("GITHUB_SYNC_RATE", "1"), 64)
+	if err != nil {
+		return nil, fmt.Errorf("invalid GITHUB_SYNC_RATE: %w", err)
+	}
+	syncBurst, err := strconv.Atoi(getenv("GITHUB_SYNC_BURST", "5"))
+	if err != nil {
+		return nil, fmt.Errorf("invalid GITHUB_SYNC_BURST: %w", err)
+	}
+	syncWorkers, err := strconv.Atoi(getenv("GITHUB_SYNC_WORKERS", "3"))
+	if err != nil {
+		return nil, fmt.Errorf("invalid GITHUB_SYNC_WORKERS: %w", err)
+	}
+	syncPoll, err := strconv.Atoi(getenv("GITHUB_SYNC_POLL_INTERVAL", "60"))
+	if err != nil {
+		return nil, fmt.Errorf("invalid GITHUB_SYNC_POLL_INTERVAL: %w", err)
+	}
+
 	cfg := &Config{
 		ListenAddr: getenv("LISTEN_ADDR", ":8000"),
 
@@ -59,13 +108,28 @@ func Load() (*Config, error) {
 		S3Bucket:    getenv("MINIO_BUCKET", "artifacts"),
 		S3Secure:    s3Secure,
 		S3Region:    getenv("MINIO_REGION", ""),
+
+		TFSigningKeyPath:       getenv("TF_SIGNING_KEY_PATH", ""),
+		TFSigningKeyPassphrase: getenv("TF_SIGNING_KEY_PASSPHRASE", ""),
+		TFProviderProtocols:    getenv("TF_PROVIDER_PROTOCOLS", "5.0,6.0"),
+
+		GitHubSyncRatePerSec:   syncRate,
+		GitHubSyncBurst:        syncBurst,
+		GitHubSyncWorkers:      syncWorkers,
+		GitHubSyncPollInterval: syncPoll,
+
+		GitHubToken:             getenv("GITHUB_TOKEN", ""),
+		GitHubAppID:             getenv("GITHUB_APP_ID", ""),
+		GitHubAppInstallationID: getenv("GITHUB_APP_INSTALLATION_ID", ""),
+		GitHubAppPrivateKey:     getenv("GITHUB_APP_PRIVATE_KEY", ""),
+		GitHubAppPrivateKeyPath: getenv("GITHUB_APP_PRIVATE_KEY_PATH", ""),
 	}
 
 	return cfg, nil
 }
 
 func getenv(key, fallback string) string {
-	if v := os.Getenv(key); v != "" {
+	if v, ok := os.LookupEnv(key); ok {
 		return v
 	}
 	return fallback

internal/config/env_test.go

@@ -0,0 +1,66 @@
+package config
+
+import (
+	"os"
+	"testing"
+)
+
+func TestLoadDefaults(t *testing.T) {
+	// Unset the vars Load reads so the fallback defaults are exercised.
+	for _, k := range []string{
+		"LISTEN_ADDR", "DBHOST", "DBPORT", "DBUSER", "DBPASS", "DBNAME", "DBSSL",
+		"REDIS_URL", "MINIO_ENDPOINT", "MINIO_ACCESS_KEY", "MINIO_SECRET_KEY",
+		"MINIO_BUCKET", "MINIO_SECURE", "MINIO_REGION",
+	} {
+		old, ok := os.LookupEnv(k)
+		os.Unsetenv(k)
+		if ok {
+			t.Cleanup(func() { os.Setenv(k, old) })
+		}
+	}
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+	if cfg.ListenAddr != ":8000" || cfg.DBPort != 5432 || cfg.DBUser != "artifacts" {
+		t.Errorf("unexpected defaults: %+v", cfg)
+	}
+	if cfg.RedisURL != "redis://localhost:6379" || cfg.S3Bucket != "artifacts" || cfg.S3Secure {
+		t.Errorf("unexpected defaults: %+v", cfg)
+	}
+}
+
+func TestLoadOverrides(t *testing.T) {
+	t.Setenv("LISTEN_ADDR", ":9999")
+	t.Setenv("DBHOST", "db.example.com")
+	t.Setenv("DBPORT", "6000")
+	t.Setenv("DBUSER", "u")
+	t.Setenv("DBPASS", "pw")
+	t.Setenv("DBNAME", "n")
+	t.Setenv("DBSSL", "require")
+	t.Setenv("MINIO_SECURE", "true")
+	t.Setenv("MINIO_REGION", "us-east-1")
+
+	cfg, err := Load()
+	if err != nil {
+		t.Fatalf("load: %v", err)
+	}
+	if cfg.ListenAddr != ":9999" || cfg.DBHost != "db.example.com" || cfg.DBPort != 6000 {
+		t.Errorf("overrides not applied: %+v", cfg)
+	}
+	if !cfg.S3Secure {
+		t.Error("MINIO_SECURE=true not parsed")
+	}
+	want := "postgres://u:pw@db.example.com:6000/n?sslmode=require"
+	if got := cfg.DatabaseDSN(); got != want {
+		t.Errorf("DSN = %q, want %q", got, want)
+	}
+}
+
+func TestLoadInvalidPort(t *testing.T) {
+	t.Setenv("DBPORT", "not-a-number")
+	if _, err := Load(); err == nil {
+		t.Error("expected error for invalid DBPORT")
+	}
+}

internal/database/alpine_github_sync.go

@@ -0,0 +1,71 @@
+package database
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// ListGitHubAlpineRemotes returns every github_alpine remote so the syncer can
+// sweep them on each poll tick.
+func (db *DB) ListGitHubAlpineRemotes(ctx context.Context) ([]models.Remote, error) {
+	rows, err := db.Pool.Query(ctx, `SELECT `+remoteCols+` FROM remotes WHERE package_type = $1 ORDER BY name`, models.PackageGitHubAlpine)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var remotes []models.Remote
+	for rows.Next() {
+		var r models.Remote
+		if err := scanRemote(rows, &r); err != nil {
+			return nil, err
+		}
+		remotes = append(remotes, r)
+	}
+	return remotes, rows.Err()
+}
+
+// ClaimGitHubAlpineSyncLease atomically claims the per-remote sync lease. It
+// succeeds only when the remote is due (never synced, or synced longer than
+// freshness ago) and no live lease is held by another replica. A zero freshness
+// (prime scans) ignores the recency gate. The returned etag is the stored
+// releases-list ETag, shared across replicas.
+func (db *DB) ClaimGitHubAlpineSyncLease(ctx context.Context, remoteName, owner string, freshness, lease time.Duration) (bool, string, error) {
+	row := db.Pool.QueryRow(ctx, `
+		INSERT INTO github_alpine_sync_state AS s (remote_name, sync_lease_owner, sync_lease_expires)
+		VALUES ($1, $2, now() + make_interval(secs => $4))
+		ON CONFLICT (remote_name) DO UPDATE
+			SET sync_lease_owner   = $2,
+			    sync_lease_expires = now() + make_interval(secs => $4)
+			WHERE (s.last_synced_at IS NULL OR s.last_synced_at < now() - make_interval(secs => $3))
+			  AND (s.sync_lease_expires IS NULL OR s.sync_lease_expires < now())
+		RETURNING s.etag
+	`, remoteName, owner, freshness.Seconds(), lease.Seconds())
+
+	var etag string
+	if err := row.Scan(&etag); err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return false, "", nil
+		}
+		return false, "", err
+	}
+	return true, etag, nil
+}
+
+// ReleaseGitHubAlpineSyncLease records the completed scan and frees the lease.
+// Only the owning replica may release; last_synced_at advances so the next poll
+// waits a full freshness window, and etag is persisted for the next conditional
+// request.
+func (db *DB) ReleaseGitHubAlpineSyncLease(ctx context.Context, remoteName, owner, etag string, syncedAt time.Time) error {
+	_, err := db.Pool.Exec(ctx, `
+		UPDATE github_alpine_sync_state
+		   SET last_synced_at = $3, etag = $4, sync_lease_owner = '', sync_lease_expires = NULL
+		 WHERE remote_name = $1 AND sync_lease_owner = $2
+	`, remoteName, owner, syncedAt, etag)
+	return err
+}

internal/database/alpine_metadata.go

@@ -0,0 +1,70 @@
+package database
+
+import (
+	"context"
+	"strings"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+)
+
+func (db *DB) InsertAlpineMetadata(ctx context.Context, meta *provider.AlpineMetadata) error {
+	_, err := db.Pool.Exec(ctx, `
+		INSERT INTO alpine_metadata (
+			repo_name, file_path, content_hash, checksum,
+			name, version, arch, download_size, installed_size,
+			description, url, license, origin, maintainer,
+			build_time, commit_hash, provider_priority,
+			depends, provides, install_if
+		) VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20)
+		ON CONFLICT (repo_name, file_path) DO NOTHING
+	`,
+		meta.RepoName, meta.FilePath, meta.ContentHash, meta.Checksum,
+		meta.Name, meta.Version, meta.Arch, meta.DownloadSize, meta.InstalledSize,
+		meta.Description, meta.URL, meta.License, meta.Origin, meta.Maintainer,
+		meta.BuildTime, meta.Commit, meta.ProviderPriority,
+		strings.Join(meta.Depends, " "), strings.Join(meta.Provides, " "), strings.Join(meta.InstallIf, " "),
+	)
+	return err
+}
+
+func (db *DB) DeleteAlpineMetadata(ctx context.Context, repoName, filePath string) error {
+	_, err := db.Pool.Exec(ctx, `DELETE FROM alpine_metadata WHERE repo_name = $1 AND file_path = $2`, repoName, filePath)
+	return err
+}
+
+func (db *DB) ListAlpineMetadataEntries(ctx context.Context, repoName string) ([]provider.AlpineMetadata, error) {
+	rows, err := db.Pool.Query(ctx, `
+		SELECT repo_name, file_path, content_hash, checksum,
+			name, version, arch, download_size, installed_size,
+			description, url, license, origin, maintainer,
+			build_time, commit_hash, provider_priority,
+			depends, provides, install_if
+		FROM alpine_metadata
+		WHERE repo_name = $1
+		ORDER BY name, version, arch, file_path
+	`, repoName)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var result []provider.AlpineMetadata
+	for rows.Next() {
+		var m provider.AlpineMetadata
+		var depends, provides, installIf string
+		if err := rows.Scan(
+			&m.RepoName, &m.FilePath, &m.ContentHash, &m.Checksum,
+			&m.Name, &m.Version, &m.Arch, &m.DownloadSize, &m.InstalledSize,
+			&m.Description, &m.URL, &m.License, &m.Origin, &m.Maintainer,
+			&m.BuildTime, &m.Commit, &m.ProviderPriority,
+			&depends, &provides, &installIf,
+		); err != nil {
+			return nil, err
+		}
+		m.Depends = strings.Fields(depends)
+		m.Provides = strings.Fields(provides)
+		m.InstallIf = strings.Fields(installIf)
+		result = append(result, m)
+	}
+	return result, rows.Err()
+}

internal/database/artifacts.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"time"
 
+	"github.com/jackc/pgx/v5"
+
 	"git.unkin.net/unkin/artifactapi/pkg/models"
 )
 
@@ -109,16 +111,49 @@ func (db *DB) InsertAccessLog(ctx context.Context, remoteName, path string, cach
 	return err
 }
 
-func (db *DB) FindOrphanedBlobs(ctx context.Context) ([]models.Blob, error) {
+// AccessLogEntry is one buffered access-log record.
+type AccessLogEntry struct {
+	RemoteName string
+	Path       string
+	CacheHit   bool
+	SizeBytes  int64
+	UpstreamMS int
+	ClientIP   string
+}
+
+// InsertAccessLogBatch bulk-inserts access-log rows with a single COPY.
+func (db *DB) InsertAccessLogBatch(ctx context.Context, entries []AccessLogEntry) error {
+	if len(entries) == 0 {
+		return nil
+	}
+	rows := make([][]any, len(entries))
+	for i, e := range entries {
+		rows[i] = []any{e.RemoteName, e.Path, e.CacheHit, e.SizeBytes, e.UpstreamMS, e.ClientIP}
+	}
+	_, err := db.Pool.CopyFrom(ctx,
+		pgx.Identifier{"access_log"},
+		[]string{"remote_name", "path", "cache_hit", "size_bytes", "upstream_ms", "client_ip"},
+		pgx.CopyFromRows(rows),
+	)
+	return err
+}
+
+// FindOrphanedBlobs returns blobs no longer referenced by any artifact or
+// local file, restricted to those created before now()-minAge. The age cutoff
+// is a grace period that avoids a TOCTOU race with in-flight dedup uploads,
+// which insert the blob row before the referencing artifact/local_files row.
+func (db *DB) FindOrphanedBlobs(ctx context.Context, minAge time.Duration) ([]models.Blob, error) {
+	cutoff := time.Now().Add(-minAge)
 	rows, err := db.Pool.Query(ctx, `
 		SELECT b.content_hash, b.s3_key, b.size_bytes, b.content_type, b.created_at
 		FROM blobs b
-		WHERE b.content_hash NOT IN (
+		WHERE b.created_at < $1
+		  AND b.content_hash NOT IN (
 			SELECT content_hash FROM artifacts
 			UNION
 			SELECT content_hash FROM local_files
 		)
-	`)
+	`, cutoff)
 	if err != nil {
 		return nil, err
 	}

internal/database/database_test.go

@@ -0,0 +1,381 @@
+package database
+
+import (
+	"context"
+	"os"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+var (
+	testDB  *DB
+	testDSN string
+)
+
+func TestMain(m *testing.M) {
+	c := context.Background()
+	dsn, terminate, err := testsupport.StartPostgres(c)
+	if err != nil {
+		// Docker unavailable: run anyway so tests self-skip via requireDB.
+		os.Exit(m.Run())
+	}
+	testDSN = dsn
+	db, err := New(dsn)
+	if err != nil {
+		terminate()
+		panic(err)
+	}
+	testDB = db
+
+	code := m.Run()
+
+	db.Close()
+	terminate()
+	// Return normally on success so the coverage profile is flushed; os.Exit
+	// would truncate it.
+	if code != 0 {
+		os.Exit(code)
+	}
+}
+
+func requireDB(t *testing.T) {
+	t.Helper()
+	if testDB == nil {
+		t.Skip("Docker unavailable; skipping database integration test")
+	}
+}
+
+func ctx() context.Context { return context.Background() }
+
+func seedRemote(t *testing.T, name string) {
+	t.Helper()
+	if err := testDB.CreateRemote(ctx(), &models.Remote{
+		Name: name, PackageType: models.PackageGeneric, RepoType: models.RepoTypeRemote,
+		BaseURL: "https://example.com", MutableTTL: 3600,
+	}); err != nil {
+		t.Fatalf("seed remote: %v", err)
+	}
+}
+
+// seedBlob inserts a blob and returns its full content hash (sha256:<hash>),
+// matching the reference convention used by artifacts and local files.
+func seedBlob(t *testing.T, hash string) string {
+	t.Helper()
+	full := "sha256:" + hash
+	if err := testDB.UpsertBlob(ctx(), full, "blobs/sha256/"+hash, 10, "application/octet-stream"); err != nil {
+		t.Fatalf("seed blob: %v", err)
+	}
+	return full
+}
+
+func TestRemotesCRUD(t *testing.T) {
+	requireDB(t)
+	seedRemote(t, "r-crud")
+	got, err := testDB.GetRemote(ctx(), "r-crud")
+	if err != nil || got.BaseURL != "https://example.com" {
+		t.Fatalf("get: %v %v", got, err)
+	}
+	got.BaseURL = "https://updated.example.com"
+	if err := testDB.UpdateRemote(ctx(), got); err != nil {
+		t.Fatalf("update: %v", err)
+	}
+	got, _ = testDB.GetRemote(ctx(), "r-crud")
+	if got.BaseURL != "https://updated.example.com" {
+		t.Errorf("update not applied: %v", got.BaseURL)
+	}
+	list, err := testDB.ListRemotes(ctx())
+	if err != nil || len(list) == 0 {
+		t.Fatalf("list: %v %v", len(list), err)
+	}
+	if err := testDB.DeleteRemote(ctx(), "r-crud"); err != nil {
+		t.Fatalf("delete: %v", err)
+	}
+	if _, err := testDB.GetRemote(ctx(), "r-crud"); err == nil {
+		t.Error("expected error after delete")
+	}
+}
+
+func TestRemoteMirrorlistRoundTrip(t *testing.T) {
+	requireDB(t)
+	mirrors := []string{"https://b.example", "https://c.example"}
+	if err := testDB.CreateRemote(ctx(), &models.Remote{
+		Name: "r-mirror", PackageType: models.PackageRPM, RepoType: models.RepoTypeRemote,
+		BaseURL: "https://a.example", Mirrorlist: mirrors, MutableTTL: 3600,
+	}); err != nil {
+		t.Fatalf("create mirrorlist remote: %v", err)
+	}
+	defer testDB.DeleteRemote(ctx(), "r-mirror")
+
+	got, err := testDB.GetRemote(ctx(), "r-mirror")
+	if err != nil {
+		t.Fatalf("get: %v", err)
+	}
+	if got.BaseURL != "https://a.example" {
+		t.Fatalf("BaseURL = %q, want https://a.example", got.BaseURL)
+	}
+	if len(got.Mirrorlist) != 2 || got.Mirrorlist[0] != mirrors[0] || got.Mirrorlist[1] != mirrors[1] {
+		t.Fatalf("Mirrorlist round-trip = %v, want %v", got.Mirrorlist, mirrors)
+	}
+	// An unset strategy is stored as the round_robin default.
+	if got.MirrorStrategy != models.MirrorStrategyRoundRobin {
+		t.Fatalf("MirrorStrategy default = %q, want %q", got.MirrorStrategy, models.MirrorStrategyRoundRobin)
+	}
+
+	// Updating to least_conn round-trips.
+	got.MirrorStrategy = models.MirrorStrategyLeastConn
+	if err := testDB.UpdateRemote(ctx(), got); err != nil {
+		t.Fatalf("update to least_conn: %v", err)
+	}
+	got, _ = testDB.GetRemote(ctx(), "r-mirror")
+	if got.MirrorStrategy != models.MirrorStrategyLeastConn {
+		t.Fatalf("MirrorStrategy after update = %q, want least_conn", got.MirrorStrategy)
+	}
+
+	// Clearing the mirrorlist on update persists an empty list.
+	got.Mirrorlist = nil
+	if err := testDB.UpdateRemote(ctx(), got); err != nil {
+		t.Fatalf("update clearing mirrorlist: %v", err)
+	}
+	got, _ = testDB.GetRemote(ctx(), "r-mirror")
+	if len(got.Mirrorlist) != 0 {
+		t.Fatalf("mirrorlist after clear = %v, want empty", got.Mirrorlist)
+	}
+}
+
+func TestArtifactsAndBlobs(t *testing.T) {
+	requireDB(t)
+	seedRemote(t, "r-art")
+	seedBlob(t, "aaaa")
+	hash := "sha256:aaaa"
+	if err := testDB.UpsertBlob(ctx(), hash, "blobs/sha256/aaaa", 10, "text/plain"); err != nil {
+		t.Fatal(err)
+	}
+	if err := testDB.UpsertArtifact(ctx(), "r-art", "path/a.txt", hash, "etag1"); err != nil {
+		t.Fatal(err)
+	}
+	// Upsert again to exercise the ON CONFLICT update branch.
+	if err := testDB.UpsertArtifact(ctx(), "r-art", "path/a.txt", hash, "etag2"); err != nil {
+		t.Fatal(err)
+	}
+	art, err := testDB.GetArtifact(ctx(), "r-art", "path/a.txt")
+	if err != nil || art.ContentHash != hash {
+		t.Fatalf("get artifact: %v %v", art, err)
+	}
+	if err := testDB.TouchArtifactAccess(ctx(), "r-art", "path/a.txt"); err != nil {
+		t.Fatal(err)
+	}
+	arts, err := testDB.ListArtifacts(ctx(), "r-art", 10, 0)
+	if err != nil || len(arts) != 1 {
+		t.Fatalf("list artifacts: %v %v", len(arts), err)
+	}
+	if err := testDB.InsertAccessLog(ctx(), "r-art", "path/a.txt", true, 10, 5, "1.2.3.4"); err != nil {
+		t.Fatal(err)
+	}
+	if err := testDB.InsertAccessLogBatch(ctx(), []AccessLogEntry{
+		{RemoteName: "r-art", Path: "b", CacheHit: false, SizeBytes: 20, UpstreamMS: 3},
+	}); err != nil {
+		t.Fatal(err)
+	}
+	if err := testDB.InsertAccessLogBatch(ctx(), nil); err != nil {
+		t.Fatalf("empty batch should be a no-op: %v", err)
+	}
+	if err := testDB.DeleteArtifact(ctx(), "r-art", "path/a.txt"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestOrphanAndColdCleanup(t *testing.T) {
+	requireDB(t)
+	seedBlob(t, "orphanhash")
+	// A blob with no artifact/local_file reference is orphaned, but only past
+	// the grace period.
+	if got, _ := testDB.FindOrphanedBlobs(ctx(), time.Hour); containsHash(got, "sha256:orphanhash") {
+		t.Error("fresh orphan should be excluded by grace period")
+	}
+	orphans, err := testDB.FindOrphanedBlobs(ctx(), -time.Hour) // cutoff in the future => include fresh
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !containsHash(orphans, "sha256:orphanhash") {
+		t.Error("expected orphan to be found with zero grace")
+	}
+	if err := testDB.DeleteBlob(ctx(), "sha256:orphanhash"); err != nil {
+		t.Fatal(err)
+	}
+
+	seedRemote(t, "r-cold")
+	seedBlob(t, "coldhash")
+	testDB.UpsertArtifact(ctx(), "r-cold", "cold.txt", "sha256:coldhash", "")
+	n, err := testDB.DeleteColdArtifacts(ctx(), "r-cold", -time.Hour) // negative => everything is "cold"
+	if err != nil || n < 1 {
+		t.Fatalf("delete cold: n=%d err=%v", n, err)
+	}
+}
+
+func containsHash(blobs []models.Blob, hash string) bool {
+	for _, b := range blobs {
+		if b.ContentHash == hash {
+			return true
+		}
+	}
+	return false
+}
+
+func TestLocalFiles(t *testing.T) {
+	requireDB(t)
+	seedRemote(t, "r-local")
+	seedBlob(t, "localhash")
+	hash := "sha256:localhash"
+	if err := testDB.CreateLocalFile(ctx(), "r-local", "foo/foo-1.0.whl", hash); err != nil {
+		t.Fatal(err)
+	}
+	// Duplicate create must be rejected.
+	if err := testDB.CreateLocalFile(ctx(), "r-local", "foo/foo-1.0.whl", hash); err == nil {
+		t.Error("expected duplicate local file error")
+	}
+	f, err := testDB.GetLocalFile(ctx(), "r-local", "foo/foo-1.0.whl")
+	if err != nil || f == nil {
+		t.Fatalf("get local file: %v %v", f, err)
+	}
+	if files, err := testDB.ListLocalFiles(ctx(), "r-local", 10, 0); err != nil || len(files) != 1 {
+		t.Fatalf("list: %v %v", len(files), err)
+	}
+	if files, err := testDB.ListLocalFilesByPrefix(ctx(), "r-local", "foo/"); err != nil || len(files) != 1 {
+		t.Fatalf("list by prefix: %v %v", len(files), err)
+	}
+	if entries, err := testDB.ListFilesByPrefix(ctx(), "r-local", "foo/"); err != nil || len(entries) != 1 {
+		t.Fatalf("provider list by prefix: %v %v", len(entries), err)
+	}
+	if pkgs, err := testDB.ListLocalFilePackages(ctx(), "r-local"); err != nil || len(pkgs) == 0 {
+		t.Fatalf("list packages: %v %v", pkgs, err)
+	}
+	if pkgs, err := testDB.ListPackages(ctx(), "r-local"); err != nil || len(pkgs) == 0 {
+		t.Fatalf("provider list packages: %v %v", pkgs, err)
+	}
+	if err := testDB.DeleteLocalFile(ctx(), "r-local", "foo/foo-1.0.whl"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestVirtualsCRUD(t *testing.T) {
+	requireDB(t)
+	if err := testDB.CreateVirtual(ctx(), &models.Virtual{
+		Name: "v-crud", PackageType: models.PackageHelm, Members: []string{"a", "b"},
+	}); err != nil {
+		t.Fatal(err)
+	}
+	v, err := testDB.GetVirtual(ctx(), "v-crud")
+	if err != nil || len(v.Members) != 2 {
+		t.Fatalf("get virtual: %v %v", v, err)
+	}
+	v.Members = []string{"a"}
+	if err := testDB.UpdateVirtual(ctx(), v); err != nil {
+		t.Fatal(err)
+	}
+	if vs, err := testDB.ListVirtuals(ctx()); err != nil || len(vs) == 0 {
+		t.Fatalf("list virtuals: %v %v", len(vs), err)
+	}
+	if err := testDB.DeleteVirtual(ctx(), "v-crud"); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestStats(t *testing.T) {
+	requireDB(t)
+	seedRemote(t, "r-stats")
+	seedBlob(t, "statshash")
+	testDB.UpsertArtifact(ctx(), "r-stats", "s.txt", "sha256:statshash", "")
+	testDB.InsertAccessLog(ctx(), "r-stats", "s.txt", true, 100, 2, "")
+
+	if _, err := testDB.GetOverviewStats(ctx()); err != nil {
+		t.Fatalf("overview: %v", err)
+	}
+	if _, err := testDB.GetTopRemotes(ctx(), 5); err != nil {
+		t.Fatalf("top remotes: %v", err)
+	}
+	if _, err := testDB.GetTopFilesByHits(ctx(), 5); err != nil {
+		t.Fatalf("top files by hits: %v", err)
+	}
+	if _, err := testDB.GetTopFilesByBandwidth(ctx(), 5); err != nil {
+		t.Fatalf("top files by bandwidth: %v", err)
+	}
+}
+
+func TestDatabaseErrorPaths(t *testing.T) {
+	requireDB(t)
+	bad, err := New(testDSN)
+	if err != nil {
+		t.Fatal(err)
+	}
+	bad.Close() // every query now fails
+	ctx := context.Background()
+
+	if _, err := bad.ListRemotes(ctx); err == nil {
+		t.Error("ListRemotes should error on closed db")
+	}
+	if _, err := bad.ListVirtuals(ctx); err == nil {
+		t.Error("ListVirtuals should error")
+	}
+	if _, err := bad.ListArtifacts(ctx, "r", 10, 0); err == nil {
+		t.Error("ListArtifacts should error")
+	}
+	if _, err := bad.ListLocalFiles(ctx, "r", 10, 0); err == nil {
+		t.Error("ListLocalFiles should error")
+	}
+	if _, err := bad.ListLocalFilesByPrefix(ctx, "r", "p"); err == nil {
+		t.Error("ListLocalFilesByPrefix should error")
+	}
+	if _, err := bad.ListLocalFilePackages(ctx, "r"); err == nil {
+		t.Error("ListLocalFilePackages should error")
+	}
+	if _, err := bad.ListFilesByPrefix(ctx, "r", "p"); err == nil {
+		t.Error("ListFilesByPrefix should error")
+	}
+	if _, err := bad.ListPackages(ctx, "r"); err == nil {
+		t.Error("ListPackages should error")
+	}
+	if _, err := bad.FindOrphanedBlobs(ctx, 0); err == nil {
+		t.Error("FindOrphanedBlobs should error")
+	}
+	if _, err := bad.GetOverviewStats(ctx); err == nil {
+		t.Error("GetOverviewStats should error")
+	}
+	if _, err := bad.GetTopRemotes(ctx, 5); err == nil {
+		t.Error("GetTopRemotes should error")
+	}
+	if _, err := bad.GetTopFilesByHits(ctx, 5); err == nil {
+		t.Error("GetTopFilesByHits should error")
+	}
+	if _, err := bad.GetTopFilesByBandwidth(ctx, 5); err == nil {
+		t.Error("GetTopFilesByBandwidth should error")
+	}
+	if _, err := bad.ListRPMMetadataEntries(ctx, "r"); err == nil {
+		t.Error("ListRPMMetadataEntries should error")
+	}
+}
+
+func TestRPMMetadata(t *testing.T) {
+	requireDB(t)
+	seedRemote(t, "r-rpm")
+	meta := &provider.RPMMetadata{
+		RepoName: "r-rpm", FilePath: "Packages/x.rpm", ContentHash: "sha256:rpm",
+		Name: "x", Version: "1.0", Release: "1", Arch: "noarch",
+		Requires: []provider.RPMDep{{Name: "libc"}},
+		Provides: []provider.RPMDep{{Name: "x"}},
+		Files:    []provider.RPMFile{},
+	}
+	if err := testDB.InsertRPMMetadata(ctx(), meta); err != nil {
+		t.Fatal(err)
+	}
+	entries, err := testDB.ListRPMMetadataEntries(ctx(), "r-rpm")
+	if err != nil || len(entries) != 1 {
+		t.Fatalf("list rpm entries: %v %v", len(entries), err)
+	}
+	if rows, err := testDB.ListRPMMetadata(ctx(), "r-rpm"); err != nil || len(rows) != 1 {
+		t.Fatalf("list rpm rows: %v %v", len(rows), err)
+	}
+}

internal/database/deb_github_sync.go

@@ -0,0 +1,70 @@
+package database
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// ListGitHubDebRemotes returns every github_deb remote so the syncer can sweep
+// them on each poll tick.
+func (db *DB) ListGitHubDebRemotes(ctx context.Context) ([]models.Remote, error) {
+	rows, err := db.Pool.Query(ctx, `SELECT `+remoteCols+` FROM remotes WHERE package_type = $1 ORDER BY name`, models.PackageGitHubDeb)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var remotes []models.Remote
+	for rows.Next() {
+		var r models.Remote
+		if err := scanRemote(rows, &r); err != nil {
+			return nil, err
+		}
+		remotes = append(remotes, r)
+	}
+	return remotes, rows.Err()
+}
+
+// ClaimGitHubDebSyncLease atomically claims the per-remote sync lease. It
+// succeeds only when the remote is due (never synced, or synced longer than
+// freshness ago) and no live lease is held by another replica. A zero freshness
+// (prime scans) ignores the recency gate. The returned etag is the stored
+// releases-list ETag, shared across replicas.
+func (db *DB) ClaimGitHubDebSyncLease(ctx context.Context, remoteName, owner string, freshness, lease time.Duration) (bool, string, error) {
+	row := db.Pool.QueryRow(ctx, `
+		INSERT INTO github_deb_sync_state AS s (remote_name, sync_lease_owner, sync_lease_expires)
+		VALUES ($1, $2, now() + make_interval(secs => $4))
+		ON CONFLICT (remote_name) DO UPDATE
+			SET sync_lease_owner   = $2,
+			    sync_lease_expires = now() + make_interval(secs => $4)
+			WHERE (s.last_synced_at IS NULL OR s.last_synced_at < now() - make_interval(secs => $3))
+			  AND (s.sync_lease_expires IS NULL OR s.sync_lease_expires < now())
+		RETURNING s.etag
+	`, remoteName, owner, freshness.Seconds(), lease.Seconds())
+
+	var etag string
+	if err := row.Scan(&etag); err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return false, "", nil
+		}
+		return false, "", err
+	}
+	return true, etag, nil
+}
+
+// ReleaseGitHubDebSyncLease records the completed scan and frees the lease. Only
+// the owning replica may release; last_synced_at advances so the next poll waits
+// a full freshness window, and etag is persisted for the next conditional request.
+func (db *DB) ReleaseGitHubDebSyncLease(ctx context.Context, remoteName, owner, etag string, syncedAt time.Time) error {
+	_, err := db.Pool.Exec(ctx, `
+		UPDATE github_deb_sync_state
+		   SET last_synced_at = $3, etag = $4, sync_lease_owner = '', sync_lease_expires = NULL
+		 WHERE remote_name = $1 AND sync_lease_owner = $2
+	`, remoteName, owner, syncedAt, etag)
+	return err
+}

internal/database/deb_github_sync_test.go

@@ -0,0 +1,90 @@
+package database
+
+import (
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+func seedGitHubDebRemote(t *testing.T, name string) {
+	t.Helper()
+	if err := testDB.CreateRemote(ctx(), &models.Remote{
+		Name: name, PackageType: models.PackageGitHubDeb, RepoType: models.RepoTypeRemote,
+		BaseURL: "https://api.github.com/repos/acme/tools", ReleasesRemote: "github", MutableTTL: 3600,
+	}); err != nil {
+		t.Fatalf("seed github_deb remote: %v", err)
+	}
+}
+
+// TestGitHubDebSyncLease exercises the real SQL: exactly one replica may hold the
+// lease, the recency window blocks a too-soon periodic re-claim, and a prime
+// (freshness 0) bypasses recency but still respects a live lease.
+func TestGitHubDebSyncLease(t *testing.T) {
+	requireDB(t)
+	name := "ghdeb-lease-" + time.Now().Format("150405.000000")
+	seedGitHubDebRemote(t, name)
+
+	const lease = 15 * time.Minute
+	freshness := time.Hour
+
+	claimed, etag, err := testDB.ClaimGitHubDebSyncLease(ctx(), name, "replica-1", freshness, lease)
+	if err != nil || !claimed {
+		t.Fatalf("replica-1 first claim: claimed=%v err=%v", claimed, err)
+	}
+	if etag != "" {
+		t.Fatalf("initial etag should be empty, got %q", etag)
+	}
+
+	claimed2, _, err := testDB.ClaimGitHubDebSyncLease(ctx(), name, "replica-2", freshness, lease)
+	if err != nil {
+		t.Fatalf("replica-2 claim err: %v", err)
+	}
+	if claimed2 {
+		t.Fatal("replica-2 claimed while replica-1 holds the lease")
+	}
+
+	if err := testDB.ReleaseGitHubDebSyncLease(ctx(), name, "replica-1", `"etag-1"`, time.Now()); err != nil {
+		t.Fatalf("release: %v", err)
+	}
+
+	claimed3, _, err := testDB.ClaimGitHubDebSyncLease(ctx(), name, "replica-2", freshness, lease)
+	if err != nil {
+		t.Fatalf("replica-2 recency claim err: %v", err)
+	}
+	if claimed3 {
+		t.Fatal("periodic claim succeeded inside the freshness window")
+	}
+
+	claimed4, etag4, err := testDB.ClaimGitHubDebSyncLease(ctx(), name, "replica-2", 0, lease)
+	if err != nil || !claimed4 {
+		t.Fatalf("prime claim: claimed=%v err=%v", claimed4, err)
+	}
+	if etag4 != `"etag-1"` {
+		t.Fatalf("prime claim etag = %q, want persisted \"etag-1\"", etag4)
+	}
+}
+
+func TestListGitHubDebRemotes(t *testing.T) {
+	requireDB(t)
+	name := "ghdeb-list-" + time.Now().Format("150405.000000")
+	seedGitHubDebRemote(t, name)
+	seedRemote(t, "generic-"+time.Now().Format("150405.000000"))
+
+	remotes, err := testDB.ListGitHubDebRemotes(ctx())
+	if err != nil {
+		t.Fatalf("list: %v", err)
+	}
+	found := false
+	for _, r := range remotes {
+		if r.PackageType != models.PackageGitHubDeb {
+			t.Fatalf("non-github_deb remote returned: %s (%s)", r.Name, r.PackageType)
+		}
+		if r.Name == name {
+			found = true
+		}
+	}
+	if !found {
+		t.Fatalf("seeded remote %q not returned", name)
+	}
+}

internal/database/deb_metadata.go

@@ -0,0 +1,57 @@
+package database
+
+import (
+	"context"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+)
+
+func (db *DB) InsertDebMetadata(ctx context.Context, meta *provider.DebMetadata) error {
+	_, err := db.Pool.Exec(ctx, `
+		INSERT INTO deb_metadata (
+			repo_name, file_path, content_hash,
+			name, version, architecture, control,
+			size, md5, sha256
+		) VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10)
+		ON CONFLICT (repo_name, file_path) DO NOTHING
+	`,
+		meta.RepoName, meta.FilePath, meta.ContentHash,
+		meta.Name, meta.Version, meta.Architecture, meta.Control,
+		meta.Size, meta.MD5, meta.SHA256,
+	)
+	return err
+}
+
+func (db *DB) DeleteDebMetadata(ctx context.Context, repoName, filePath string) error {
+	_, err := db.Pool.Exec(ctx, `DELETE FROM deb_metadata WHERE repo_name = $1 AND file_path = $2`, repoName, filePath)
+	return err
+}
+
+func (db *DB) ListDebMetadataEntries(ctx context.Context, repoName string) ([]provider.DebMetadata, error) {
+	rows, err := db.Pool.Query(ctx, `
+		SELECT repo_name, file_path, content_hash,
+			name, version, architecture, control,
+			size, md5, sha256, created_at
+		FROM deb_metadata
+		WHERE repo_name = $1
+		ORDER BY name, version, architecture, file_path
+	`, repoName)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var result []provider.DebMetadata
+	for rows.Next() {
+		var m provider.DebMetadata
+		if err := rows.Scan(
+			&m.RepoName, &m.FilePath, &m.ContentHash,
+			&m.Name, &m.Version, &m.Architecture, &m.Control,
+			&m.Size, &m.MD5, &m.SHA256, &m.CreatedAt,
+		); err != nil {
+			return nil, err
+		}
+		result = append(result, m)
+	}
+	return result, rows.Err()
+}

internal/database/github_sync.go

@@ -0,0 +1,73 @@
+package database
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/jackc/pgx/v5"
+
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// ListGitHubRPMRemotes returns every github_rpm remote so the syncer can sweep
+// them on each poll tick.
+func (db *DB) ListGitHubRPMRemotes(ctx context.Context) ([]models.Remote, error) {
+	rows, err := db.Pool.Query(ctx, `SELECT `+remoteCols+` FROM remotes WHERE package_type = $1 ORDER BY name`, models.PackageGitHubRPM)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var remotes []models.Remote
+	for rows.Next() {
+		var r models.Remote
+		if err := scanRemote(rows, &r); err != nil {
+			return nil, err
+		}
+		remotes = append(remotes, r)
+	}
+	return remotes, rows.Err()
+}
+
+// ClaimGitHubSyncLease atomically claims the per-remote sync lease. It succeeds
+// (claimed=true) only when the remote is due — never synced, or synced longer
+// than freshness ago — and no live lease is held by another replica. This bounds
+// total GitHub load to roughly one scan per freshness window regardless of how
+// many replicas poll. The returned etag is the stored releases-list ETag, shared
+// across replicas so a conditional request can short-circuit an unchanged repo.
+// A zero freshness (used for prime scans) ignores the recency gate and claims
+// whenever no live lease is held.
+func (db *DB) ClaimGitHubSyncLease(ctx context.Context, remoteName, owner string, freshness, lease time.Duration) (bool, string, error) {
+	row := db.Pool.QueryRow(ctx, `
+		INSERT INTO github_rpm_sync_state AS s (remote_name, sync_lease_owner, sync_lease_expires)
+		VALUES ($1, $2, now() + make_interval(secs => $4))
+		ON CONFLICT (remote_name) DO UPDATE
+			SET sync_lease_owner   = $2,
+			    sync_lease_expires = now() + make_interval(secs => $4)
+			WHERE (s.last_synced_at IS NULL OR s.last_synced_at < now() - make_interval(secs => $3))
+			  AND (s.sync_lease_expires IS NULL OR s.sync_lease_expires < now())
+		RETURNING s.etag
+	`, remoteName, owner, freshness.Seconds(), lease.Seconds())
+
+	var etag string
+	if err := row.Scan(&etag); err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return false, "", nil
+		}
+		return false, "", err
+	}
+	return true, etag, nil
+}
+
+// ReleaseGitHubSyncLease records the completed scan and frees the lease. Only the
+// owning replica may release; last_synced_at advances so the next poll waits a
+// full freshness window, and etag is persisted for the next conditional request.
+func (db *DB) ReleaseGitHubSyncLease(ctx context.Context, remoteName, owner, etag string, syncedAt time.Time) error {
+	_, err := db.Pool.Exec(ctx, `
+		UPDATE github_rpm_sync_state
+		   SET last_synced_at = $3, etag = $4, sync_lease_owner = '', sync_lease_expires = NULL
+		 WHERE remote_name = $1 AND sync_lease_owner = $2
+	`, remoteName, owner, syncedAt, etag)
+	return err
+}

internal/database/github_sync_test.go

@@ -0,0 +1,95 @@
+package database
+
+import (
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+func seedGitHubRPMRemote(t *testing.T, name string) {
+	t.Helper()
+	if err := testDB.CreateRemote(ctx(), &models.Remote{
+		Name: name, PackageType: models.PackageGitHubRPM, RepoType: models.RepoTypeRemote,
+		BaseURL: "https://api.github.com/repos/acme/tools", ReleasesRemote: "github", MutableTTL: 3600,
+	}); err != nil {
+		t.Fatalf("seed github_rpm remote: %v", err)
+	}
+}
+
+// TestGitHubSyncLease exercises the real SQL: exactly one replica may hold the
+// lease, the recency window blocks a too-soon periodic re-claim, and a prime
+// (freshness 0) bypasses recency but still respects a live lease.
+func TestGitHubSyncLease(t *testing.T) {
+	requireDB(t)
+	name := "gh-lease-" + time.Now().Format("150405.000000")
+	seedGitHubRPMRemote(t, name)
+
+	const lease = 15 * time.Minute
+	freshness := time.Hour
+
+	// First claim on a never-synced remote wins; etag starts empty.
+	claimed, etag, err := testDB.ClaimGitHubSyncLease(ctx(), name, "replica-1", freshness, lease)
+	if err != nil || !claimed {
+		t.Fatalf("replica-1 first claim: claimed=%v err=%v", claimed, err)
+	}
+	if etag != "" {
+		t.Fatalf("initial etag should be empty, got %q", etag)
+	}
+
+	// A second replica cannot claim while the lease is held.
+	claimed2, _, err := testDB.ClaimGitHubSyncLease(ctx(), name, "replica-2", freshness, lease)
+	if err != nil {
+		t.Fatalf("replica-2 claim err: %v", err)
+	}
+	if claimed2 {
+		t.Fatal("replica-2 claimed while replica-1 holds the lease")
+	}
+
+	// Replica 1 finishes: record the sync and persist an etag.
+	if err := testDB.ReleaseGitHubSyncLease(ctx(), name, "replica-1", `"etag-1"`, time.Now()); err != nil {
+		t.Fatalf("release: %v", err)
+	}
+
+	// A periodic re-claim inside the freshness window is blocked by recency.
+	claimed3, _, err := testDB.ClaimGitHubSyncLease(ctx(), name, "replica-2", freshness, lease)
+	if err != nil {
+		t.Fatalf("replica-2 recency claim err: %v", err)
+	}
+	if claimed3 {
+		t.Fatal("periodic claim succeeded inside the freshness window")
+	}
+
+	// A prime (freshness 0) bypasses recency and reads the persisted etag.
+	claimed4, etag4, err := testDB.ClaimGitHubSyncLease(ctx(), name, "replica-2", 0, lease)
+	if err != nil || !claimed4 {
+		t.Fatalf("prime claim: claimed=%v err=%v", claimed4, err)
+	}
+	if etag4 != `"etag-1"` {
+		t.Fatalf("prime claim etag = %q, want persisted \"etag-1\"", etag4)
+	}
+}
+
+func TestListGitHubRPMRemotes(t *testing.T) {
+	requireDB(t)
+	name := "gh-list-" + time.Now().Format("150405.000000")
+	seedGitHubRPMRemote(t, name)
+	seedRemote(t, "generic-"+time.Now().Format("150405.000000"))
+
+	remotes, err := testDB.ListGitHubRPMRemotes(ctx())
+	if err != nil {
+		t.Fatalf("list: %v", err)
+	}
+	found := false
+	for _, r := range remotes {
+		if r.PackageType != models.PackageGitHubRPM {
+			t.Fatalf("non-github_rpm remote returned: %s (%s)", r.Name, r.PackageType)
+		}
+		if r.Name == name {
+			found = true
+		}
+	}
+	if !found {
+		t.Fatalf("seeded remote %q not returned", name)
+	}
+}

internal/database/local_files.go

@@ -10,6 +10,7 @@ import (
 	"github.com/jackc/pgx/v5/pgconn"
 
 	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
 )
 
 type LocalFile struct {
@@ -37,6 +38,20 @@ func (db *DB) CreateLocalFile(ctx context.Context, repoName, filePath, contentHa
 	return nil
 }
 
+// UpsertLocalFile inserts a local file or repoints an existing path at a new
+// blob. Unlike CreateLocalFile it never errors on a duplicate path — it is for
+// mutable references such as Docker tags, where re-pushing a tag must move it to
+// the newly-pushed manifest rather than being rejected as an overwrite.
+func (db *DB) UpsertLocalFile(ctx context.Context, repoName, filePath, contentHash string) error {
+	_, err := db.Pool.Exec(ctx, `
+		INSERT INTO local_files (repo_name, file_path, content_hash)
+		VALUES ($1, $2, $3)
+		ON CONFLICT (repo_name, file_path)
+		DO UPDATE SET content_hash = EXCLUDED.content_hash, created_at = NOW()
+	`, repoName, filePath, contentHash)
+	return err
+}
+
 func (db *DB) GetLocalFile(ctx context.Context, repoName, filePath string) (*LocalFile, error) {
 	row := db.Pool.QueryRow(ctx, `
 		SELECT id, repo_name, file_path, content_hash, created_at
@@ -78,6 +93,40 @@ func (db *DB) ListLocalFiles(ctx context.Context, repoName string, limit, offset
 	return files, rows.Err()
 }
 
+// ListLocalArtifacts returns a repo's local files shaped as models.Artifact so
+// the UI's cached-objects view can render them the same way as remote artifacts.
+// Local files carry no access/fetch counters, so those are left at zero and the
+// timestamps are all derived from created_at.
+func (db *DB) ListLocalArtifacts(ctx context.Context, repoName string, limit, offset int) ([]models.Artifact, error) {
+	rows, err := db.Pool.Query(ctx, `
+		SELECT lf.id, lf.repo_name, lf.file_path, lf.content_hash,
+			lf.created_at, b.size_bytes, b.content_type
+		FROM local_files lf
+		JOIN blobs b ON lf.content_hash = b.content_hash
+		WHERE lf.repo_name = $1
+		ORDER BY lf.file_path
+		LIMIT $2 OFFSET $3
+	`, repoName, limit, offset)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var artifacts []models.Artifact
+	for rows.Next() {
+		var a models.Artifact
+		var createdAt time.Time
+		if err := rows.Scan(&a.ID, &a.RemoteName, &a.Path, &a.ContentHash, &createdAt, &a.SizeBytes, &a.ContentType); err != nil {
+			return nil, err
+		}
+		a.FirstSeenAt = createdAt
+		a.LastFetchedAt = createdAt
+		a.LastAccessedAt = createdAt
+		artifacts = append(artifacts, a)
+	}
+	return artifacts, rows.Err()
+}
+
 func (db *DB) ListLocalFilesByPrefix(ctx context.Context, repoName, prefix string) ([]LocalFile, error) {
 	rows, err := db.Pool.Query(ctx, `
 		SELECT id, repo_name, file_path, content_hash, created_at

internal/database/postgres.go

@@ -44,6 +44,8 @@ func (db *DB) migrate() error {
 			package_type    TEXT NOT NULL,
 			repo_type       TEXT DEFAULT 'remote',
 			base_url        TEXT NOT NULL DEFAULT '',
+			mirrorlist      TEXT[] DEFAULT '{}',
+			mirror_strategy TEXT NOT NULL DEFAULT 'round_robin',
 			description     TEXT DEFAULT '',
 			username        TEXT DEFAULT '',
 			password        TEXT DEFAULT '',
@@ -124,6 +126,11 @@ func (db *DB) migrate() error {
 		CREATE INDEX IF NOT EXISTS idx_access_log_remote_time ON access_log(remote_name, created_at);
 
 		ALTER TABLE remotes ADD COLUMN IF NOT EXISTS repo_type TEXT DEFAULT 'remote';
+		ALTER TABLE remotes ADD COLUMN IF NOT EXISTS mirrorlist TEXT[] DEFAULT '{}';
+		ALTER TABLE remotes ADD COLUMN IF NOT EXISTS mirror_strategy TEXT NOT NULL DEFAULT 'round_robin';
+		ALTER TABLE remotes ADD COLUMN IF NOT EXISTS upstream_dial_timeout INTEGER DEFAULT 0;
+		ALTER TABLE remotes ADD COLUMN IF NOT EXISTS upstream_tls_timeout INTEGER DEFAULT 0;
+		ALTER TABLE remotes ADD COLUMN IF NOT EXISTS upstream_response_header_timeout INTEGER DEFAULT 0;
 
 		CREATE TABLE IF NOT EXISTS rpm_metadata (
 			id              BIGSERIAL PRIMARY KEY,
@@ -148,6 +155,8 @@ func (db *DB) migrate() error {
 			packager        TEXT DEFAULT '',
 			requires        JSONB DEFAULT '[]',
 			provides        JSONB DEFAULT '[]',
+			conflicts       JSONB DEFAULT '[]',
+			obsoletes       JSONB DEFAULT '[]',
 			files           JSONB DEFAULT '[]',
 			changelogs      JSONB DEFAULT '[]',
 			created_at      TIMESTAMPTZ DEFAULT NOW(),
@@ -155,6 +164,87 @@ func (db *DB) migrate() error {
 		);
 
 		CREATE INDEX IF NOT EXISTS idx_rpm_metadata_repo ON rpm_metadata(repo_name);
+
+		ALTER TABLE rpm_metadata ADD COLUMN IF NOT EXISTS conflicts JSONB DEFAULT '[]';
+		ALTER TABLE rpm_metadata ADD COLUMN IF NOT EXISTS obsoletes JSONB DEFAULT '[]';
+
+		CREATE TABLE IF NOT EXISTS deb_metadata (
+			id              BIGSERIAL PRIMARY KEY,
+			repo_name       TEXT NOT NULL,
+			file_path       TEXT NOT NULL,
+			content_hash    TEXT NOT NULL,
+			name            TEXT NOT NULL,
+			version         TEXT NOT NULL,
+			architecture    TEXT NOT NULL,
+			control         TEXT NOT NULL,
+			size            BIGINT DEFAULT 0,
+			md5             TEXT DEFAULT '',
+			sha256          TEXT DEFAULT '',
+			created_at      TIMESTAMPTZ DEFAULT NOW(),
+			UNIQUE(repo_name, file_path)
+		);
+
+		CREATE INDEX IF NOT EXISTS idx_deb_metadata_repo ON deb_metadata(repo_name);
+
+		CREATE TABLE IF NOT EXISTS alpine_metadata (
+			id                BIGSERIAL PRIMARY KEY,
+			repo_name         TEXT NOT NULL,
+			file_path         TEXT NOT NULL,
+			content_hash      TEXT NOT NULL,
+			checksum          TEXT NOT NULL,
+			name              TEXT NOT NULL,
+			version           TEXT NOT NULL,
+			arch              TEXT NOT NULL,
+			download_size     BIGINT DEFAULT 0,
+			installed_size    BIGINT DEFAULT 0,
+			description       TEXT DEFAULT '',
+			url               TEXT DEFAULT '',
+			license           TEXT DEFAULT '',
+			origin            TEXT DEFAULT '',
+			maintainer        TEXT DEFAULT '',
+			build_time        BIGINT DEFAULT 0,
+			commit_hash       TEXT DEFAULT '',
+			provider_priority TEXT DEFAULT '',
+			depends           TEXT DEFAULT '',
+			provides          TEXT DEFAULT '',
+			install_if        TEXT DEFAULT '',
+			created_at        TIMESTAMPTZ DEFAULT NOW(),
+			UNIQUE(repo_name, file_path)
+		);
+
+		CREATE INDEX IF NOT EXISTS idx_alpine_metadata_repo ON alpine_metadata(repo_name);
+		CREATE INDEX IF NOT EXISTS idx_alpine_metadata_repo_arch ON alpine_metadata(repo_name, arch);
+
+		CREATE TABLE IF NOT EXISTS github_rpm_sync_state (
+			remote_name        TEXT PRIMARY KEY,
+			etag               TEXT DEFAULT '',
+			last_synced_at     TIMESTAMPTZ,
+			sync_lease_owner   TEXT DEFAULT '',
+			sync_lease_expires TIMESTAMPTZ
+		);
+
+		CREATE TABLE IF NOT EXISTS github_deb_sync_state (
+			remote_name        TEXT PRIMARY KEY,
+			etag               TEXT DEFAULT '',
+			last_synced_at     TIMESTAMPTZ,
+			sync_lease_owner   TEXT DEFAULT '',
+			sync_lease_expires TIMESTAMPTZ
+		);
+
+		CREATE TABLE IF NOT EXISTS github_alpine_sync_state (
+			remote_name        TEXT PRIMARY KEY,
+			etag               TEXT DEFAULT '',
+			last_synced_at     TIMESTAMPTZ,
+			sync_lease_owner   TEXT DEFAULT '',
+			sync_lease_expires TIMESTAMPTZ
+		);
+
+		CREATE TABLE IF NOT EXISTS signing_keys (
+			purpose             TEXT PRIMARY KEY,
+			private_key_armor   TEXT NOT NULL,
+			key_id              TEXT NOT NULL,
+			created_at          TIMESTAMPTZ DEFAULT NOW()
+		);
 	`)
 	return err
 }

internal/database/remotes.go

@@ -6,21 +6,34 @@ import (
 	"git.unkin.net/unkin/artifactapi/pkg/models"
 )
 
-const remoteCols = `name, package_type, repo_type, base_url, description, username, password,
+const remoteCols = `name, package_type, repo_type, base_url, mirrorlist, mirror_strategy, description, username, password,
 	immutable_ttl, mutable_ttl, check_mutable,
 	patterns, blocklist, mutable_patterns, immutable_patterns,
 	ban_tags_enabled, ban_tags,
 	quarantine_enabled, quarantine_days, stale_on_error,
-	releases_remote, managed_by, created_at, updated_at`
+	releases_remote, managed_by,
+	upstream_dial_timeout, upstream_tls_timeout, upstream_response_header_timeout,
+	created_at, updated_at`
+
+// normalizeMirrorStrategy maps an empty strategy to the round_robin default so
+// the NOT NULL mirror_strategy column always stores a canonical value.
+func normalizeMirrorStrategy(s string) string {
+	if s == "" {
+		return models.MirrorStrategyRoundRobin
+	}
+	return s
+}
 
 func scanRemote(scanner interface{ Scan(...any) error }, r *models.Remote) error {
 	return scanner.Scan(
-		&r.Name, &r.PackageType, &r.RepoType, &r.BaseURL, &r.Description, &r.Username, &r.Password,
+		&r.Name, &r.PackageType, &r.RepoType, &r.BaseURL, &r.Mirrorlist, &r.MirrorStrategy, &r.Description, &r.Username, &r.Password,
 		&r.ImmutableTTL, &r.MutableTTL, &r.CheckMutable,
 		&r.Patterns, &r.Blocklist, &r.MutablePatterns, &r.ImmutablePatterns,
 		&r.BanTagsEnabled, &r.BanTags,
 		&r.QuarantineEnabled, &r.QuarantineDays, &r.StaleOnError,
-		&r.ReleasesRemote, &r.ManagedBy, &r.CreatedAt, &r.UpdatedAt,
+		&r.ReleasesRemote, &r.ManagedBy,
+		&r.UpstreamDialTimeout, &r.UpstreamTLSTimeout, &r.UpstreamResponseHeaderTimeout,
+		&r.CreatedAt, &r.UpdatedAt,
 	)
 }
 
@@ -54,20 +67,24 @@ func (db *DB) ListRemotes(ctx context.Context) ([]models.Remote, error) {
 func (db *DB) CreateRemote(ctx context.Context, r *models.Remote) error {
 	_, err := db.Pool.Exec(ctx, `
 		INSERT INTO remotes (
-			name, package_type, repo_type, base_url, description, username, password,
+			name, package_type, repo_type, base_url, mirrorlist, description, username, password,
 			immutable_ttl, mutable_ttl, check_mutable,
 			patterns, blocklist, mutable_patterns, immutable_patterns,
 			ban_tags_enabled, ban_tags,
 			quarantine_enabled, quarantine_days, stale_on_error,
-			releases_remote, managed_by
-		) VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,$21)
+			releases_remote, managed_by,
+			upstream_dial_timeout, upstream_tls_timeout, upstream_response_header_timeout,
+			mirror_strategy
+		) VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,$21,$22,$23,$24,$25,$26)
 	`,
-		r.Name, r.PackageType, r.RepoType, r.BaseURL, r.Description, r.Username, r.Password,
+		r.Name, r.PackageType, r.RepoType, r.BaseURL, r.Mirrorlist, r.Description, r.Username, r.Password,
 		r.ImmutableTTL, r.MutableTTL, r.CheckMutable,
 		r.Patterns, r.Blocklist, r.MutablePatterns, r.ImmutablePatterns,
 		r.BanTagsEnabled, r.BanTags,
 		r.QuarantineEnabled, r.QuarantineDays, r.StaleOnError,
 		r.ReleasesRemote, r.ManagedBy,
+		r.UpstreamDialTimeout, r.UpstreamTLSTimeout, r.UpstreamResponseHeaderTimeout,
+		normalizeMirrorStrategy(r.MirrorStrategy),
 	)
 	return err
 }
@@ -75,12 +92,15 @@ func (db *DB) CreateRemote(ctx context.Context, r *models.Remote) error {
 func (db *DB) UpdateRemote(ctx context.Context, r *models.Remote) error {
 	_, err := db.Pool.Exec(ctx, `
 		UPDATE remotes SET
-			package_type=$2, repo_type=$3, base_url=$4, description=$5, username=$6, password=$7,
+			package_type=$2, repo_type=$3, base_url=$4, mirrorlist=$25, description=$5, username=$6, password=$7,
 			immutable_ttl=$8, mutable_ttl=$9, check_mutable=$10,
 			patterns=$11, blocklist=$12, mutable_patterns=$13, immutable_patterns=$14,
 			ban_tags_enabled=$15, ban_tags=$16,
 			quarantine_enabled=$17, quarantine_days=$18, stale_on_error=$19,
-			releases_remote=$20, managed_by=$21, updated_at=NOW()
+			releases_remote=$20, managed_by=$21,
+			upstream_dial_timeout=$22, upstream_tls_timeout=$23, upstream_response_header_timeout=$24,
+			mirror_strategy=$26,
+			updated_at=NOW()
 		WHERE name=$1
 	`,
 		r.Name, r.PackageType, r.RepoType, r.BaseURL, r.Description, r.Username, r.Password,
@@ -89,6 +109,9 @@ func (db *DB) UpdateRemote(ctx context.Context, r *models.Remote) error {
 		r.BanTagsEnabled, r.BanTags,
 		r.QuarantineEnabled, r.QuarantineDays, r.StaleOnError,
 		r.ReleasesRemote, r.ManagedBy,
+		r.UpstreamDialTimeout, r.UpstreamTLSTimeout, r.UpstreamResponseHeaderTimeout,
+		r.Mirrorlist,
+		normalizeMirrorStrategy(r.MirrorStrategy),
 	)
 	return err
 }

internal/database/rpm_metadata.go

@@ -3,6 +3,7 @@ package database
 import (
 	"context"
 	"encoding/json"
+	"time"
 
 	"git.unkin.net/unkin/artifactapi/internal/provider"
 )
@@ -10,6 +11,8 @@ import (
 func (db *DB) InsertRPMMetadata(ctx context.Context, meta *provider.RPMMetadata) error {
 	requiresJSON, _ := json.Marshal(meta.Requires)
 	providesJSON, _ := json.Marshal(meta.Provides)
+	conflictsJSON, _ := json.Marshal(meta.Conflicts)
+	obsoletesJSON, _ := json.Marshal(meta.Obsoletes)
 	filesJSON, _ := json.Marshal(meta.Files)
 	changelogsJSON, _ := json.Marshal(meta.Changelogs)
 
@@ -19,19 +22,24 @@ func (db *DB) InsertRPMMetadata(ctx context.Context, meta *provider.RPMMetadata)
 			name, epoch, version, release, arch,
 			summary, description, rpm_size, installed_size,
 			license, vendor, build_group, build_host, source_rpm, url, packager,
-			requires, provides, files, changelogs
-		) VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,$21,$22,$23)
+			requires, provides, conflicts, obsoletes, files, changelogs
+		) VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,$21,$22,$23,$24,$25)
 		ON CONFLICT (repo_name, file_path) DO NOTHING
 	`,
 		meta.RepoName, meta.FilePath, meta.ContentHash,
 		meta.Name, meta.Epoch, meta.Version, meta.Release, meta.Arch,
 		meta.Summary, meta.Description, meta.RPMSize, meta.InstalledSize,
 		meta.License, meta.Vendor, meta.Group, meta.BuildHost, meta.SourceRPM, meta.URL, meta.Packager,
-		requiresJSON, providesJSON, filesJSON, changelogsJSON,
+		requiresJSON, providesJSON, conflictsJSON, obsoletesJSON, filesJSON, changelogsJSON,
 	)
 	return err
 }
 
+func (db *DB) DeleteRPMMetadata(ctx context.Context, repoName, filePath string) error {
+	_, err := db.Pool.Exec(ctx, `DELETE FROM rpm_metadata WHERE repo_name = $1 AND file_path = $2`, repoName, filePath)
+	return err
+}
+
 type RPMMetadataRow struct {
 	RepoName      string
 	FilePath      string
@@ -54,8 +62,11 @@ type RPMMetadataRow struct {
 	Packager      string
 	Requires      json.RawMessage
 	Provides      json.RawMessage
+	Conflicts     json.RawMessage
+	Obsoletes     json.RawMessage
 	Files         json.RawMessage
 	Changelogs    json.RawMessage
+	CreatedAt     time.Time
 }
 
 func (db *DB) ListRPMMetadataEntries(ctx context.Context, repoName string) ([]provider.RPMMetadata, error) {
@@ -85,9 +96,12 @@ func (db *DB) ListRPMMetadataEntries(ctx context.Context, repoName string) ([]pr
 			SourceRPM:     r.SourceRPM,
 			URL:           r.URL,
 			Packager:      r.Packager,
+			CreatedAt:     r.CreatedAt,
 		}
 		json.Unmarshal(r.Requires, &meta.Requires)
 		json.Unmarshal(r.Provides, &meta.Provides)
+		json.Unmarshal(r.Conflicts, &meta.Conflicts)
+		json.Unmarshal(r.Obsoletes, &meta.Obsoletes)
 		json.Unmarshal(r.Files, &meta.Files)
 		json.Unmarshal(r.Changelogs, &meta.Changelogs)
 		result[i] = meta
@@ -101,10 +115,11 @@ func (db *DB) ListRPMMetadata(ctx context.Context, repoName string) ([]RPMMetada
 			name, epoch, version, release, arch,
 			summary, description, rpm_size, installed_size,
 			license, vendor, build_group, build_host, source_rpm, url, packager,
-			requires, provides, files, changelogs
+			requires, provides, conflicts, obsoletes, files, changelogs,
+			created_at
 		FROM rpm_metadata
 		WHERE repo_name = $1
-		ORDER BY name, epoch, version, release, arch
+		ORDER BY name, epoch, version, release, arch, file_path
 	`, repoName)
 	if err != nil {
 		return nil, err
@@ -119,7 +134,8 @@ func (db *DB) ListRPMMetadata(ctx context.Context, repoName string) ([]RPMMetada
 			&r.Name, &r.Epoch, &r.Version, &r.Release, &r.Arch,
 			&r.Summary, &r.Description, &r.RPMSize, &r.InstalledSize,
 			&r.License, &r.Vendor, &r.Group, &r.BuildHost, &r.SourceRPM, &r.URL, &r.Packager,
-			&r.Requires, &r.Provides, &r.Files, &r.Changelogs,
+			&r.Requires, &r.Provides, &r.Conflicts, &r.Obsoletes, &r.Files, &r.Changelogs,
+			&r.CreatedAt,
 		); err != nil {
 			return nil, err
 		}

internal/database/signing_keys.go

@@ -0,0 +1,35 @@
+package database
+
+import (
+	"context"
+	"errors"
+
+	"github.com/jackc/pgx/v5"
+)
+
+// GetSigningKey returns the stored armored private key and key id for a purpose.
+// found is false when no key has been generated yet.
+func (db *DB) GetSigningKey(ctx context.Context, purpose string) (armor, keyID string, found bool, err error) {
+	row := db.Pool.QueryRow(ctx, `
+		SELECT private_key_armor, key_id FROM signing_keys WHERE purpose = $1
+	`, purpose)
+	if err := row.Scan(&armor, &keyID); err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return "", "", false, nil
+		}
+		return "", "", false, err
+	}
+	return armor, keyID, true, nil
+}
+
+// InsertSigningKeyIfAbsent stores a freshly generated key, doing nothing if
+// another replica already inserted one. Callers re-read with GetSigningKey to
+// pick up whichever key won the race.
+func (db *DB) InsertSigningKeyIfAbsent(ctx context.Context, purpose, armor, keyID string) error {
+	_, err := db.Pool.Exec(ctx, `
+		INSERT INTO signing_keys (purpose, private_key_armor, key_id)
+		VALUES ($1, $2, $3)
+		ON CONFLICT (purpose) DO NOTHING
+	`, purpose, armor, keyID)
+	return err
+}

internal/database/signing_keys_test.go

@@ -0,0 +1,31 @@
+package database
+
+import "testing"
+
+func TestSigningKeyRoundTripAndIdempotency(t *testing.T) {
+	requireDB(t)
+
+	const purpose = "terraform-provider-test"
+
+	// Absent to start.
+	if _, _, found, err := testDB.GetSigningKey(ctx(), purpose); err != nil || found {
+		t.Fatalf("expected no key, got found=%v err=%v", found, err)
+	}
+
+	if err := testDB.InsertSigningKeyIfAbsent(ctx(), purpose, "ARMOR-1", "KEYID1"); err != nil {
+		t.Fatal(err)
+	}
+
+	// A second insert must not overwrite (models the replica race).
+	if err := testDB.InsertSigningKeyIfAbsent(ctx(), purpose, "ARMOR-2", "KEYID2"); err != nil {
+		t.Fatal(err)
+	}
+
+	armor, keyID, found, err := testDB.GetSigningKey(ctx(), purpose)
+	if err != nil || !found {
+		t.Fatalf("expected key, found=%v err=%v", found, err)
+	}
+	if armor != "ARMOR-1" || keyID != "KEYID1" {
+		t.Errorf("key was overwritten: armor=%q key_id=%q", armor, keyID)
+	}
+}

internal/database/stats.go

@@ -30,6 +30,15 @@ func (db *DB) GetOverviewStats(ctx context.Context) (*models.OverviewStats, erro
 		return nil, err
 	}
 
+	err = db.Pool.QueryRow(ctx, `
+		SELECT COALESCE(SUM(size_bytes), 0)
+		FROM access_log
+		WHERE cache_hit = TRUE AND created_at > NOW() - INTERVAL '30 days'
+	`).Scan(&stats.BandwidthSaved30d)
+	if err != nil {
+		return nil, err
+	}
+
 	return &stats, nil
 }
 

internal/gc/gc.go

@@ -9,6 +9,16 @@ import (
 	"git.unkin.net/unkin/artifactapi/internal/storage"
 )
 
+// blobGracePeriod is how old an orphaned blob must be before GC will delete
+// it. This avoids racing in-flight dedup uploads that insert the blob row
+// before the referencing artifact/local_files row exists.
+const blobGracePeriod = 1 * time.Hour
+
+// uploadGracePeriod is how long a docker blob-upload staging object
+// (uploads/<uuid>) may sit idle before GC treats it as an abandoned push and
+// reaps it. Generous so a slow but live push is never cut off mid-flight.
+const uploadGracePeriod = 24 * time.Hour
+
 type Collector struct {
 	db       *database.DB
 	store    *storage.S3
@@ -38,7 +48,9 @@ func (c *Collector) Run(ctx context.Context) {
 func (c *Collector) sweep(ctx context.Context) {
 	start := time.Now()
 
-	orphaned, err := c.db.FindOrphanedBlobs(ctx)
+	c.sweepUploads(ctx)
+
+	orphaned, err := c.db.FindOrphanedBlobs(ctx, blobGracePeriod)
 	if err != nil {
 		slog.Error("gc: find orphaned blobs", "error", err)
 		return
@@ -65,3 +77,24 @@ func (c *Collector) sweep(ctx context.Context) {
 		)
 	}
 }
+
+// sweepUploads reaps docker blob-upload staging objects abandoned longer than
+// uploadGracePeriod (cancelled or interrupted pushes that never finalised).
+func (c *Collector) sweepUploads(ctx context.Context) {
+	stale, err := c.store.ListStaleObjects(ctx, "uploads/", time.Now().Add(-uploadGracePeriod))
+	if err != nil {
+		slog.Error("gc: list stale uploads", "error", err)
+		return
+	}
+	reaped := 0
+	for _, key := range stale {
+		if err := c.store.Delete(ctx, key); err != nil {
+			slog.Warn("gc: delete stale upload", "key", key, "error", err)
+			continue
+		}
+		reaped++
+	}
+	if reaped > 0 {
+		slog.Info("gc: reaped stale docker uploads", "count", reaped)
+	}
+}

internal/gc/gc_integration_test.go

@@ -0,0 +1,114 @@
+package gc
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/internal/database"
+	"git.unkin.net/unkin/artifactapi/internal/storage"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+)
+
+var (
+	testDB    *database.DB
+	testStore *storage.S3
+)
+
+func TestMain(m *testing.M) {
+	ctx := context.Background()
+	dsn, termPG, err := testsupport.StartPostgres(ctx)
+	if err != nil {
+		os.Exit(m.Run())
+	}
+	minio, termMinio, err := testsupport.StartMinio(ctx)
+	if err != nil {
+		termPG()
+		os.Exit(m.Run())
+	}
+	db, err := database.New(dsn)
+	if err != nil {
+		panic(err)
+	}
+	var s3 *storage.S3
+	for i := 0; i < 20; i++ {
+		if s3, err = storage.NewS3(minio.Endpoint, minio.AccessKey, minio.SecretKey, "gc-test", false, ""); err == nil {
+			break
+		}
+		time.Sleep(500 * time.Millisecond)
+	}
+	if err != nil {
+		panic(err)
+	}
+	testDB = db
+	testStore = s3
+
+	code := m.Run()
+	db.Close()
+	termMinio()
+	termPG()
+	if code != 0 {
+		os.Exit(code)
+	}
+}
+
+func TestSweepDeletesOldOrphan(t *testing.T) {
+	if testDB == nil {
+		t.Skip("Docker unavailable")
+	}
+	ctx := context.Background()
+	hash := "sha256:gcorphan"
+	key := storage.BlobKey("gcorphan")
+
+	if err := testStore.Upload(ctx, key, bytes.NewReader([]byte("orphan")), 6, "application/octet-stream"); err != nil {
+		t.Fatal(err)
+	}
+	if err := testDB.UpsertBlob(ctx, hash, key, 6, "application/octet-stream"); err != nil {
+		t.Fatal(err)
+	}
+	// Age the blob past the grace period.
+	if _, err := testDB.Pool.Exec(ctx, `UPDATE blobs SET created_at = now() - interval '2 hours' WHERE content_hash = $1`, hash); err != nil {
+		t.Fatal(err)
+	}
+
+	c := New(testDB, testStore, time.Hour)
+	c.sweep(ctx)
+
+	if exists, _ := testStore.Exists(ctx, key); exists {
+		t.Error("expected orphan object deleted from store")
+	}
+	orphans, _ := testDB.FindOrphanedBlobs(ctx, 0)
+	for _, b := range orphans {
+		if b.ContentHash == hash {
+			t.Error("expected orphan blob row deleted")
+		}
+	}
+}
+
+func TestSweepNoOrphans(t *testing.T) {
+	if testDB == nil {
+		t.Skip("Docker unavailable")
+	}
+	// A sweep with nothing to collect should be a clean no-op.
+	New(testDB, testStore, time.Hour).sweep(context.Background())
+}
+
+func TestRunStopsOnContextCancel(t *testing.T) {
+	if testDB == nil {
+		t.Skip("Docker unavailable")
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	done := make(chan struct{})
+	go func() {
+		New(testDB, testStore, time.Hour).Run(ctx)
+		close(done)
+	}()
+	cancel()
+	select {
+	case <-done:
+	case <-time.After(5 * time.Second):
+		t.Fatal("Run did not return after context cancel")
+	}
+}

internal/githubauth/app.go

@@ -0,0 +1,199 @@
+package githubauth
+
+import (
+	"context"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/json"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"sync"
+	"time"
+)
+
+const (
+	defaultAPIBase = "https://api.github.com"
+
+	// jwtLifetime is how long the app JWT is valid. GitHub caps it at 10 minutes;
+	// 9 leaves headroom for clock skew.
+	jwtLifetime = 9 * time.Minute
+	// jwtBackdate backdates iat to tolerate the app server's clock running behind
+	// GitHub's, which otherwise rejects the JWT.
+	jwtBackdate = 60 * time.Second
+	// refreshSkew refreshes the installation token this long before it expires so
+	// a request never races an expiry.
+	refreshSkew = 5 * time.Minute
+)
+
+type httpDoer interface {
+	Do(*http.Request) (*http.Response, error)
+}
+
+// appCredential mints installation access tokens for a GitHub App. It signs a
+// short-lived RS256 JWT with the app private key, exchanges it for a ~1h
+// installation token, caches that token, and refreshes it shortly before expiry.
+// Refreshes are single-flighted by holding the mutex across the exchange, so
+// concurrent callers coalesce onto one HTTP request and reuse the cached token.
+type appCredential struct {
+	appID          string
+	installationID string
+	key            *rsa.PrivateKey
+	apiBase        string
+	client         httpDoer
+
+	mu     sync.Mutex
+	token  string
+	expiry time.Time
+}
+
+func newAppCredential(opts Options) (*appCredential, error) {
+	if opts.AppID == "" {
+		return nil, errors.New("github app: GITHUB_APP_ID is required")
+	}
+	if opts.InstallationID == "" {
+		return nil, errors.New("github app: GITHUB_APP_INSTALLATION_ID is required")
+	}
+	pemBytes, err := loadPrivateKeyPEM(opts)
+	if err != nil {
+		return nil, err
+	}
+	key, err := parseRSAPrivateKey(pemBytes)
+	if err != nil {
+		return nil, err
+	}
+
+	apiBase := opts.apiBaseURL
+	if apiBase == "" {
+		apiBase = defaultAPIBase
+	}
+	client := opts.httpClient
+	if client == nil {
+		client = &http.Client{Timeout: 30 * time.Second}
+	}
+
+	return &appCredential{
+		appID:          opts.AppID,
+		installationID: opts.InstallationID,
+		key:            key,
+		apiBase:        strings.TrimRight(apiBase, "/"),
+		client:         client,
+	}, nil
+}
+
+// Token returns a cached installation token, refreshing it under a single-flight
+// lock when it is missing or within refreshSkew of expiry.
+func (a *appCredential) Token(ctx context.Context) (string, error) {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	if a.token != "" && time.Now().Before(a.expiry.Add(-refreshSkew)) {
+		return a.token, nil
+	}
+	if err := a.refreshLocked(ctx); err != nil {
+		return "", err
+	}
+	return a.token, nil
+}
+
+func (a *appCredential) refreshLocked(ctx context.Context) error {
+	jwt, err := mintJWT(a.appID, a.key, time.Now())
+	if err != nil {
+		return fmt.Errorf("github app: mint jwt: %w", err)
+	}
+
+	u := fmt.Sprintf("%s/app/installations/%s/access_tokens", a.apiBase, a.installationID)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, u, nil)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Authorization", "Bearer "+jwt)
+	req.Header.Set("Accept", "application/vnd.github+json")
+	req.Header.Set("X-GitHub-Api-Version", "2022-11-28")
+
+	resp, err := a.client.Do(req)
+	if err != nil {
+		return fmt.Errorf("github app: token exchange: %w", err)
+	}
+	defer resp.Body.Close()
+	body, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	if resp.StatusCode != http.StatusCreated && resp.StatusCode != http.StatusOK {
+		// Never echo the body verbatim — it can contain sensitive material.
+		return fmt.Errorf("github app: token exchange status %d", resp.StatusCode)
+	}
+
+	var out struct {
+		Token     string    `json:"token"`
+		ExpiresAt time.Time `json:"expires_at"`
+	}
+	if err := json.Unmarshal(body, &out); err != nil {
+		return fmt.Errorf("github app: decode token response: %w", err)
+	}
+	if out.Token == "" {
+		return errors.New("github app: token exchange returned an empty token")
+	}
+	a.token = out.Token
+	a.expiry = out.ExpiresAt
+	if a.expiry.IsZero() {
+		// Defensive: assume the documented ~1h lifetime if GitHub omits it.
+		a.expiry = time.Now().Add(time.Hour)
+	}
+	return nil
+}
+
+// mintJWT builds and RS256-signs a GitHub App JWT (iss=app id, backdated iat,
+// ≤10m exp) using stdlib crypto — no third-party JWT dependency.
+func mintJWT(appID string, key *rsa.PrivateKey, now time.Time) (string, error) {
+	header := map[string]string{"alg": "RS256", "typ": "JWT"}
+	claims := map[string]any{
+		"iat": now.Add(-jwtBackdate).Unix(),
+		"exp": now.Add(jwtLifetime).Unix(),
+		"iss": appID,
+	}
+	hb, err := json.Marshal(header)
+	if err != nil {
+		return "", err
+	}
+	cb, err := json.Marshal(claims)
+	if err != nil {
+		return "", err
+	}
+	signingInput := b64url(hb) + "." + b64url(cb)
+	digest := sha256.Sum256([]byte(signingInput))
+	sig, err := rsa.SignPKCS1v15(rand.Reader, key, crypto.SHA256, digest[:])
+	if err != nil {
+		return "", err
+	}
+	return signingInput + "." + b64url(sig), nil
+}
+
+func b64url(b []byte) string {
+	return base64.RawURLEncoding.EncodeToString(b)
+}
+
+// parseRSAPrivateKey accepts PKCS#1 ("RSA PRIVATE KEY") and PKCS#8 ("PRIVATE
+// KEY") PEM, covering both GitHub App key export formats.
+func parseRSAPrivateKey(pemBytes []byte) (*rsa.PrivateKey, error) {
+	block, _ := pem.Decode(pemBytes)
+	if block == nil {
+		return nil, errors.New("github app: private key is not valid PEM")
+	}
+	if key, err := x509.ParsePKCS1PrivateKey(block.Bytes); err == nil {
+		return key, nil
+	}
+	keyAny, err := x509.ParsePKCS8PrivateKey(block.Bytes)
+	if err != nil {
+		return nil, errors.New("github app: private key is not a supported RSA PKCS#1/PKCS#8 key")
+	}
+	rsaKey, ok := keyAny.(*rsa.PrivateKey)
+	if !ok {
+		return nil, errors.New("github app: private key is not an RSA key")
+	}
+	return rsaKey, nil
+}

internal/githubauth/app_test.go

@@ -0,0 +1,207 @@
+package githubauth
+
+import (
+	"context"
+	"crypto"
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/json"
+	"encoding/pem"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+)
+
+func testRSAKeyPEM(t *testing.T) string {
+	t.Helper()
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		t.Fatalf("generate key: %v", err)
+	}
+	der := x509.MarshalPKCS1PrivateKey(key)
+	return string(pem.EncodeToMemory(&pem.Block{Type: "RSA PRIVATE KEY", Bytes: der}))
+}
+
+// appFixture serves the installation-token exchange endpoint, records requests,
+// verifies the presented JWT against the app public key, and returns tokens with
+// a controllable expiry.
+type appFixture struct {
+	srv       *httptest.Server
+	pub       *rsa.PublicKey
+	mu        sync.Mutex
+	exchanges int
+	lastJWT   string
+	expiresAt func() time.Time
+	tokenSeq  int
+}
+
+func newAppFixture(t *testing.T, pemKey string) *appFixture {
+	t.Helper()
+	block, _ := pem.Decode([]byte(pemKey))
+	key, err := x509.ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		t.Fatalf("parse test key: %v", err)
+	}
+	f := &appFixture{
+		pub:       &key.PublicKey,
+		expiresAt: func() time.Time { return time.Now().Add(time.Hour) },
+	}
+	mux := http.NewServeMux()
+	mux.HandleFunc("/app/installations/456/access_tokens", func(w http.ResponseWriter, r *http.Request) {
+		auth := r.Header.Get("Authorization")
+		jwt := strings.TrimPrefix(auth, "Bearer ")
+		f.mu.Lock()
+		f.exchanges++
+		f.lastJWT = jwt
+		f.tokenSeq++
+		seq := f.tokenSeq
+		exp := f.expiresAt()
+		f.mu.Unlock()
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusCreated)
+		json.NewEncoder(w).Encode(map[string]any{
+			"token":      fmt.Sprintf("ghs_installation_%d", seq),
+			"expires_at": exp.UTC().Format(time.RFC3339),
+		})
+	})
+	f.srv = httptest.NewServer(mux)
+	t.Cleanup(f.srv.Close)
+	return f
+}
+
+func (f *appFixture) verifyJWT(t *testing.T) {
+	t.Helper()
+	f.mu.Lock()
+	jwt := f.lastJWT
+	f.mu.Unlock()
+	parts := strings.Split(jwt, ".")
+	if len(parts) != 3 {
+		t.Fatalf("jwt not three-part: %q", jwt)
+	}
+	signingInput := parts[0] + "." + parts[1]
+	sig, err := base64.RawURLEncoding.DecodeString(parts[2])
+	if err != nil {
+		t.Fatalf("decode sig: %v", err)
+	}
+	digest := sha256.Sum256([]byte(signingInput))
+	if err := rsa.VerifyPKCS1v15(f.pub, crypto.SHA256, digest[:], sig); err != nil {
+		t.Fatalf("jwt signature invalid: %v", err)
+	}
+	var claims struct {
+		Iss string `json:"iss"`
+		Iat int64  `json:"iat"`
+		Exp int64  `json:"exp"`
+	}
+	cb, _ := base64.RawURLEncoding.DecodeString(parts[1])
+	if err := json.Unmarshal(cb, &claims); err != nil {
+		t.Fatalf("decode claims: %v", err)
+	}
+	if claims.Iss != "123" {
+		t.Fatalf("iss = %q, want 123", claims.Iss)
+	}
+	if claims.Exp-claims.Iat > int64((10*time.Minute)/time.Second) {
+		t.Fatalf("jwt lifetime exceeds 10m: iat=%d exp=%d", claims.Iat, claims.Exp)
+	}
+	if claims.Iat > time.Now().Unix() {
+		t.Fatalf("iat not backdated: %d", claims.Iat)
+	}
+}
+
+func newAppCred(t *testing.T, f *appFixture, pemKey string) *appCredential {
+	t.Helper()
+	c, err := newAppCredential(Options{
+		AppID:          "123",
+		InstallationID: "456",
+		PrivateKeyPEM:  pemKey,
+		apiBaseURL:     f.srv.URL,
+		httpClient:     f.srv.Client(),
+	})
+	if err != nil {
+		t.Fatalf("newAppCredential: %v", err)
+	}
+	return c
+}
+
+func TestApp_MintsJWTAndExchangesForInstallationToken(t *testing.T) {
+	pemKey := testRSAKeyPEM(t)
+	f := newAppFixture(t, pemKey)
+	c := newAppCred(t, f, pemKey)
+
+	tok, err := c.Token(context.Background())
+	if err != nil {
+		t.Fatalf("token: %v", err)
+	}
+	if tok != "ghs_installation_1" {
+		t.Fatalf("token = %q, want ghs_installation_1", tok)
+	}
+	if f.exchanges != 1 {
+		t.Fatalf("exchanges = %d, want 1", f.exchanges)
+	}
+	f.verifyJWT(t)
+}
+
+func TestApp_CachesInstallationToken(t *testing.T) {
+	pemKey := testRSAKeyPEM(t)
+	f := newAppFixture(t, pemKey)
+	c := newAppCred(t, f, pemKey)
+
+	for i := 0; i < 5; i++ {
+		if _, err := c.Token(context.Background()); err != nil {
+			t.Fatalf("token: %v", err)
+		}
+	}
+	if f.exchanges != 1 {
+		t.Fatalf("exchanges = %d, want 1 (token should be cached)", f.exchanges)
+	}
+}
+
+func TestApp_RefreshesNearExpiry(t *testing.T) {
+	pemKey := testRSAKeyPEM(t)
+	f := newAppFixture(t, pemKey)
+	// Token expires within refreshSkew, so every call must re-exchange.
+	f.expiresAt = func() time.Time { return time.Now().Add(2 * time.Minute) }
+	c := newAppCred(t, f, pemKey)
+
+	t1, err := c.Token(context.Background())
+	if err != nil {
+		t.Fatalf("token 1: %v", err)
+	}
+	t2, err := c.Token(context.Background())
+	if err != nil {
+		t.Fatalf("token 2: %v", err)
+	}
+	if f.exchanges != 2 {
+		t.Fatalf("exchanges = %d, want 2 (near-expiry token must refresh)", f.exchanges)
+	}
+	if t1 == t2 {
+		t.Fatalf("expected a fresh token after refresh, both = %q", t1)
+	}
+}
+
+func TestApp_ConcurrentTokenSingleFlights(t *testing.T) {
+	pemKey := testRSAKeyPEM(t)
+	f := newAppFixture(t, pemKey)
+	c := newAppCred(t, f, pemKey)
+
+	var wg sync.WaitGroup
+	for i := 0; i < 20; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			if _, err := c.Token(context.Background()); err != nil {
+				t.Errorf("token: %v", err)
+			}
+		}()
+	}
+	wg.Wait()
+	if f.exchanges != 1 {
+		t.Fatalf("exchanges = %d, want 1 (concurrent calls must coalesce)", f.exchanges)
+	}
+}

internal/githubauth/credential.go

@@ -0,0 +1,106 @@
+// Package githubauth provides the process-wide GitHub machine credential used to
+// authenticate every outbound GitHub request (releases scan, ranged asset header
+// fetches, and the generic-github byte proxy for private assets). The credential
+// is delivered via env/secret only — it is never stored per-remote in the DB,
+// never returned by any API, and never logged.
+package githubauth
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+	"sync"
+)
+
+// Credential yields a bearer token for GitHub requests. Token may block to mint
+// or refresh (the GitHub App path); an empty string means "no auth", which only
+// happens when no credential is configured.
+type Credential interface {
+	Token(ctx context.Context) (string, error)
+}
+
+// Options is the raw, env-sourced auth configuration. Exactly one mode may be
+// configured: a static token, or a GitHub App (id + installation id + private
+// key). Partial App configuration is an error (fail closed); no fields at all is
+// fine and yields a nil credential (anonymous, current behavior).
+type Options struct {
+	// Token is a Personal Access Token (fine-grained or classic) sent verbatim
+	// as "Authorization: Bearer <token>".
+	Token string
+
+	// GitHub App fields. PrivateKeyPEM and PrivateKeyPath are alternatives; the
+	// inline PEM wins when both are set.
+	AppID          string
+	InstallationID string
+	PrivateKeyPEM  string
+	PrivateKeyPath string
+
+	// apiBaseURL overrides https://api.github.com for tests. Empty uses the real
+	// endpoint. httpClient likewise overrides the default client for tests.
+	apiBaseURL string
+	httpClient httpDoer
+}
+
+// New builds the process credential from options, validating that auth is either
+// fully configured or fully absent. It returns (nil, nil) when nothing is set.
+func New(opts Options) (Credential, error) {
+	hasToken := opts.Token != ""
+	hasAppField := opts.AppID != "" || opts.InstallationID != "" ||
+		opts.PrivateKeyPEM != "" || opts.PrivateKeyPath != ""
+
+	switch {
+	case !hasToken && !hasAppField:
+		return nil, nil // no auth configured — anonymous is fine
+	case hasToken && hasAppField:
+		return nil, errors.New("github auth: both a token and GitHub App fields are set; configure exactly one")
+	case hasToken:
+		return staticToken{token: opts.Token}, nil
+	default:
+		return newAppCredential(opts)
+	}
+}
+
+// staticToken is a fixed PAT credential.
+type staticToken struct{ token string }
+
+func (s staticToken) Token(context.Context) (string, error) { return s.token, nil }
+
+// server is the process-wide credential set once at startup. A nil value means
+// no server credential (anonymous). Access is guarded so a late SetServer in a
+// test is race-free.
+var (
+	serverMu sync.RWMutex
+	server   Credential
+)
+
+// SetServer installs the process credential. Call once during startup.
+func SetServer(c Credential) {
+	serverMu.Lock()
+	server = c
+	serverMu.Unlock()
+}
+
+// Server returns the process credential, or nil if none is configured.
+func Server() Credential {
+	serverMu.RLock()
+	defer serverMu.RUnlock()
+	return server
+}
+
+// loadPrivateKeyPEM resolves the App private key bytes from the inline PEM or a
+// file path, without ever returning the key material in an error message.
+func loadPrivateKeyPEM(opts Options) ([]byte, error) {
+	if strings.TrimSpace(opts.PrivateKeyPEM) != "" {
+		return []byte(opts.PrivateKeyPEM), nil
+	}
+	if opts.PrivateKeyPath != "" {
+		b, err := os.ReadFile(opts.PrivateKeyPath)
+		if err != nil {
+			return nil, fmt.Errorf("github app: read private key file: %w", err)
+		}
+		return b, nil
+	}
+	return nil, errors.New("github app: no private key configured")
+}

internal/githubauth/credential_test.go

@@ -0,0 +1,77 @@
+package githubauth
+
+import (
+	"context"
+	"testing"
+)
+
+func TestNew_NoConfigIsAnonymous(t *testing.T) {
+	c, err := New(Options{})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if c != nil {
+		t.Fatalf("expected nil credential when nothing configured, got %T", c)
+	}
+}
+
+func TestNew_TokenMode(t *testing.T) {
+	c, err := New(Options{Token: "ghp_example"})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	tok, err := c.Token(context.Background())
+	if err != nil {
+		t.Fatalf("token: %v", err)
+	}
+	if tok != "ghp_example" {
+		t.Fatalf("token = %q, want ghp_example", tok)
+	}
+}
+
+func TestNew_TokenAndAppConflict(t *testing.T) {
+	_, err := New(Options{Token: "ghp_example", AppID: "123"})
+	if err == nil {
+		t.Fatal("expected error when both token and app fields are set")
+	}
+}
+
+func TestNew_PartialAppFailsClosed(t *testing.T) {
+	cases := map[string]Options{
+		"app id without key":  {AppID: "123", InstallationID: "456"},
+		"key without app id":  {InstallationID: "456", PrivateKeyPEM: testRSAKeyPEM(t)},
+		"app id without inst": {AppID: "123", PrivateKeyPEM: testRSAKeyPEM(t)},
+	}
+	for name, opts := range cases {
+		t.Run(name, func(t *testing.T) {
+			if _, err := New(opts); err == nil {
+				t.Fatalf("expected fail-closed error for %q", name)
+			}
+		})
+	}
+}
+
+func TestNew_AppModeParsesKey(t *testing.T) {
+	c, err := New(Options{
+		AppID:          "123",
+		InstallationID: "456",
+		PrivateKeyPEM:  testRSAKeyPEM(t),
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if _, ok := c.(*appCredential); !ok {
+		t.Fatalf("expected *appCredential, got %T", c)
+	}
+}
+
+func TestNew_AppModeRejectsBadKey(t *testing.T) {
+	_, err := New(Options{
+		AppID:          "123",
+		InstallationID: "456",
+		PrivateKeyPEM:  "-----BEGIN RSA PRIVATE KEY-----\nnope\n-----END RSA PRIVATE KEY-----",
+	})
+	if err == nil {
+		t.Fatal("expected error for malformed private key")
+	}
+}

internal/provider/alpine/alpine.go

@@ -1,12 +1,27 @@
 package alpine
 
 import (
+	"bufio"
+	"bytes"
+	"compress/gzip"
 	"context"
+	"crypto/sha1"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
 	"net/http"
+	"path"
+	"strconv"
 	"strings"
+	"time"
+
+	"archive/tar"
 
 	"git.unkin.net/unkin/artifactapi/internal/auth"
 	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/storage"
 	"git.unkin.net/unkin/artifactapi/pkg/models"
 )
 
@@ -46,3 +61,349 @@ func (p *Provider) RewriteResponse(_ []byte, _ models.Remote, _ string) ([]byte,
 func (p *Provider) AuthHeaders(_ context.Context, remote models.Remote) (http.Header, error) {
 	return auth.BasicHeaders(remote), nil
 }
+
+// --- LocalUploader: hosting real .apk packages -----------------------------
+
+// ValidateUpload accepts any *.apk and preserves the client-supplied directory
+// (the arch prefix) as the storage path, since arch cannot be parsed from the
+// filename alone and the generic uploader hands us only the path. apk clients
+// fetch packages at <arch>/<file>.apk, so publishers upload to that same path;
+// AfterUpload records the true arch (from .PKGINFO) for index filtering.
+func (p *Provider) ValidateUpload(filePath string) (storagePath, contentType string, err error) {
+	clean := strings.TrimPrefix(path.Clean("/"+filePath), "/")
+	filename := clean
+	if i := strings.LastIndex(clean, "/"); i >= 0 {
+		filename = clean[i+1:]
+	}
+	if !strings.HasSuffix(strings.ToLower(filename), ".apk") {
+		return "", "", fmt.Errorf("file must be a .apk package")
+	}
+	return clean, "application/vnd.android.package-archive", nil
+}
+
+func (p *Provider) UploadResponse(storagePath, contentHash string, sizeBytes int64) map[string]any {
+	filename := storagePath
+	if i := strings.LastIndex(storagePath, "/"); i >= 0 {
+		filename = storagePath[i+1:]
+	}
+	return map[string]any{
+		"filename":     filename,
+		"content_hash": contentHash,
+		"size_bytes":   sizeBytes,
+	}
+}
+
+func (p *Provider) AfterUpload(ctx context.Context, repoName, storagePath, contentHash string, blobs provider.BlobReader, db provider.MetadataStore) {
+	s3Key := storage.BlobKey(strings.TrimPrefix(contentHash, "sha256:"))
+
+	reader, blobSize, err := blobs.Download(ctx, s3Key)
+	if err != nil {
+		slog.Error("alpine metadata: download failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	defer reader.Close()
+
+	raw, err := io.ReadAll(reader)
+	if err != nil {
+		slog.Error("alpine metadata: read failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+
+	meta, err := parseApk(raw)
+	if err != nil {
+		slog.Error("alpine metadata: parse failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	meta.RepoName = repoName
+	meta.FilePath = storagePath
+	meta.ContentHash = contentHash
+	meta.DownloadSize = blobSize
+
+	if meta.Name == "" || meta.Arch == "" {
+		slog.Error("alpine metadata: .PKGINFO missing pkgname/arch", "repo", repoName, "path", storagePath)
+		return
+	}
+
+	store, ok := db.(provider.AlpineMetadataStore)
+	if !ok {
+		slog.Error("alpine metadata: store does not support alpine metadata", "repo", repoName)
+		return
+	}
+	if err := store.InsertAlpineMetadata(ctx, meta); err != nil {
+		slog.Error("alpine metadata: insert failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	slog.Info("alpine metadata: parsed", "repo", repoName, "name", meta.Name, "version", meta.Version, "arch", meta.Arch)
+}
+
+func (p *Provider) AfterDelete(ctx context.Context, repoName, storagePath string, db provider.MetadataDeleter) error {
+	deleter, ok := db.(provider.AlpineMetadataDeleter)
+	if !ok {
+		return nil
+	}
+	if err := deleter.DeleteAlpineMetadata(ctx, repoName, storagePath); err != nil {
+		slog.Error("alpine metadata: delete failed", "repo", repoName, "path", storagePath, "error", err)
+		return err
+	}
+	slog.Info("alpine metadata: deleted", "repo", repoName, "path", storagePath)
+	return nil
+}
+
+// --- LocalIndexer: generating a per-arch APKINDEX.tar.gz -------------------
+
+// normalizeIndexPath collapses apk's dot-segment prefix: an /etc/apk/repositories
+// line of "<url>/api/v1/local/<name>" makes apk request "./<arch>/APKINDEX.tar.gz".
+// Mirrors deb's flat-repo normalization.
+func normalizeIndexPath(p string) string {
+	return strings.TrimPrefix(path.Clean("/"+p), "/")
+}
+
+func (p *Provider) ServeLocalIndex(w http.ResponseWriter, r *http.Request, files provider.FileStore, repoName, reqPath string) bool {
+	clean := normalizeIndexPath(reqPath)
+	if !strings.HasSuffix(clean, "APKINDEX.tar.gz") {
+		return false
+	}
+	arch := strings.TrimSuffix(clean, "APKINDEX.tar.gz")
+	arch = strings.Trim(arch, "/")
+	if arch == "" || strings.Contains(arch, "/") {
+		http.Error(w, "APKINDEX must be requested per-arch: <arch>/APKINDEX.tar.gz", http.StatusNotFound)
+		return true
+	}
+
+	reader, ok := files.(provider.AlpineMetadataReader)
+	if !ok {
+		http.Error(w, "alpine metadata not available", http.StatusInternalServerError)
+		return true
+	}
+
+	metas, err := reader.ListAlpineMetadataEntries(r.Context(), repoName)
+	if err != nil {
+		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+			slog.Warn("alpine: metadata read canceled", "repo", repoName, "error", err)
+			http.Error(w, "metadata read canceled", http.StatusServiceUnavailable)
+			return true
+		}
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return true
+	}
+
+	var filtered []provider.AlpineMetadata
+	for _, m := range metas {
+		if m.Arch == arch {
+			filtered = append(filtered, m)
+		}
+	}
+
+	w.Header().Set("Content-Type", "application/gzip")
+	w.WriteHeader(http.StatusOK)
+	w.Write(generateAPKIndex(filtered))
+	return true
+}
+
+func (p *Provider) GenerateLocalIndex(ctx context.Context, files provider.FileStore, repoName, path string) ([]byte, error) {
+	return nil, fmt.Errorf("alpine local index generation for virtual repos not supported")
+}
+
+// --- pure-Go .apk parsing --------------------------------------------------
+
+// parseApk reads an .apk (up to three concatenated, independently gzipped tar
+// streams: optional signature, control, data). It locates the control stream by
+// its .PKGINFO member, computes the apk pull checksum C: = "Q1" +
+// base64(sha1(<control gzip stream bytes>)), and reads the .PKGINFO fields.
+func parseApk(raw []byte) (*provider.AlpineMetadata, error) {
+	members, err := gzipMembers(raw)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, m := range members {
+		pkginfo, ok := pkginfoFromTar(m.tar)
+		if !ok {
+			continue
+		}
+		meta := parsePkginfo(pkginfo)
+		sum := sha1.Sum(m.raw)
+		meta.Checksum = "Q1" + base64.StdEncoding.EncodeToString(sum[:])
+		return meta, nil
+	}
+	return nil, errors.New("no .PKGINFO found in any .apk gzip stream")
+}
+
+type gzMember struct {
+	raw []byte // the raw bytes of this gzip stream (for the Q1 checksum)
+	tar []byte // the decompressed tar payload
+}
+
+// gzipMembers splits the concatenated gzip streams, returning each stream's raw
+// bytes alongside its decompressed tar. It relies on bytes.Reader being an
+// io.ByteReader (so compress/gzip does not over-read past a member's trailer)
+// to recover exact stream boundaries via Multistream(false)+Reset.
+func gzipMembers(data []byte) ([]gzMember, error) {
+	br := bytes.NewReader(data)
+	zr, err := gzip.NewReader(br)
+	if err != nil {
+		return nil, err
+	}
+	var members []gzMember
+	prev := 0
+	for {
+		zr.Multistream(false)
+		out, err := io.ReadAll(zr)
+		if err != nil {
+			return nil, err
+		}
+		end := len(data) - br.Len()
+		members = append(members, gzMember{raw: data[prev:end], tar: out})
+		prev = end
+		if err := zr.Reset(br); err != nil {
+			if err == io.EOF {
+				break
+			}
+			return nil, err
+		}
+	}
+	return members, nil
+}
+
+func pkginfoFromTar(tarBytes []byte) (string, bool) {
+	tr := tar.NewReader(bytes.NewReader(tarBytes))
+	for {
+		hdr, err := tr.Next()
+		if err != nil {
+			return "", false
+		}
+		if strings.TrimPrefix(hdr.Name, "./") == ".PKGINFO" {
+			b, err := io.ReadAll(tr)
+			if err != nil {
+				return "", false
+			}
+			return string(b), true
+		}
+	}
+}
+
+// parsePkginfo reads the "key = value" .PKGINFO text, collecting the repeated
+// depend/provides/install_if keys into slices.
+func parsePkginfo(text string) *provider.AlpineMetadata {
+	m := &provider.AlpineMetadata{}
+	sc := bufio.NewScanner(strings.NewReader(text))
+	sc.Buffer(make([]byte, 0, 64*1024), 1024*1024)
+	for sc.Scan() {
+		line := strings.TrimSpace(sc.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		idx := strings.Index(line, "=")
+		if idx < 0 {
+			continue
+		}
+		key := strings.TrimSpace(line[:idx])
+		val := strings.TrimSpace(line[idx+1:])
+		switch key {
+		case "pkgname":
+			m.Name = val
+		case "pkgver":
+			m.Version = val
+		case "arch":
+			m.Arch = val
+		case "pkgdesc":
+			m.Description = val
+		case "url":
+			m.URL = val
+		case "license":
+			m.License = val
+		case "origin":
+			m.Origin = val
+		case "maintainer":
+			m.Maintainer = val
+		case "builddate":
+			if n, err := strconv.ParseInt(val, 10, 64); err == nil {
+				m.BuildTime = n
+			}
+		case "commit":
+			m.Commit = val
+		case "size":
+			if n, err := strconv.ParseInt(val, 10, 64); err == nil {
+				m.InstalledSize = n
+			}
+		case "provider_priority":
+			m.ProviderPriority = val
+		case "depend":
+			if val != "" {
+				m.Depends = append(m.Depends, val)
+			}
+		case "provides":
+			if val != "" {
+				m.Provides = append(m.Provides, val)
+			}
+		case "install_if":
+			if val != "" {
+				m.InstallIf = append(m.InstallIf, val)
+			}
+		}
+	}
+	return m
+}
+
+// generateAPKIndex builds the APKINDEX.tar.gz = gzip(tar(APKINDEX)) for the
+// given (already arch-filtered) rows. Records are blank-line separated; fields
+// follow the canonical C/P/V/A/S/I/T/U/L/o/m/t/c/k/D/p/i order and empties are
+// omitted. Unsigned (clients use --allow-untrusted), matching rpm gpgcheck=0.
+func generateAPKIndex(metas []provider.AlpineMetadata) []byte {
+	var idx bytes.Buffer
+	for i, m := range metas {
+		if i > 0 {
+			idx.WriteString("\n")
+		}
+		writeField(&idx, "C", m.Checksum)
+		writeField(&idx, "P", m.Name)
+		writeField(&idx, "V", m.Version)
+		writeField(&idx, "A", m.Arch)
+		writeField(&idx, "S", intField(m.DownloadSize))
+		writeField(&idx, "I", intField(m.InstalledSize))
+		writeField(&idx, "T", m.Description)
+		writeField(&idx, "U", m.URL)
+		writeField(&idx, "L", m.License)
+		writeField(&idx, "o", m.Origin)
+		writeField(&idx, "m", m.Maintainer)
+		writeField(&idx, "t", intField(m.BuildTime))
+		writeField(&idx, "c", m.Commit)
+		writeField(&idx, "k", m.ProviderPriority)
+		writeField(&idx, "D", strings.Join(m.Depends, " "))
+		writeField(&idx, "p", strings.Join(m.Provides, " "))
+		writeField(&idx, "i", strings.Join(m.InstallIf, " "))
+	}
+
+	var tarBuf bytes.Buffer
+	tw := tar.NewWriter(&tarBuf)
+	body := idx.Bytes()
+	// ModTime is pinned to the Unix epoch (never wall clock) so APKINDEX.tar.gz
+	// is byte-identical across replicas and regenerations (issue #117); apk
+	// clients ignore the tar mtime.
+	tw.WriteHeader(&tar.Header{Name: "APKINDEX", Mode: 0o644, Size: int64(len(body)), Typeflag: tar.TypeReg, ModTime: time.Unix(0, 0)})
+	tw.Write(body)
+	tw.Close()
+
+	var gzBuf bytes.Buffer
+	gz := gzip.NewWriter(&gzBuf)
+	gz.Write(tarBuf.Bytes())
+	gz.Close()
+	return gzBuf.Bytes()
+}
+
+func writeField(b *bytes.Buffer, key, val string) {
+	if val == "" {
+		return
+	}
+	b.WriteString(key)
+	b.WriteString(":")
+	b.WriteString(val)
+	b.WriteString("\n")
+}
+
+func intField(n int64) string {
+	if n == 0 {
+		return ""
+	}
+	return strconv.FormatInt(n, 10)
+}

internal/provider/alpine/alpine_deterministic_test.go

@@ -0,0 +1,72 @@
+package alpine
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"io"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+)
+
+func apkFixture() []provider.AlpineMetadata {
+	return []provider.AlpineMetadata{
+		{
+			RepoName: "r", FilePath: "x86_64/aaa-1.0-r0.apk", Checksum: "Q1aaa",
+			Name: "aaa", Version: "1.0-r0", Arch: "x86_64", DownloadSize: 100, InstalledSize: 10,
+			Description: "pkg aaa", URL: "https://a", License: "MIT",
+			Depends: []string{"so:libc"}, Provides: []string{"cmd:aaa"}, BuildTime: 1710000000,
+		},
+		{
+			RepoName: "r", FilePath: "x86_64/bbb-2.0-r0.apk", Checksum: "Q1bbb",
+			Name: "bbb", Version: "2.0-r0", Arch: "x86_64", DownloadSize: 200, InstalledSize: 20,
+		},
+	}
+}
+
+// TestAPKIndexDeterministic asserts APKINDEX.tar.gz is byte-identical across two
+// generations separated by wall-clock time, so the two no-affinity replicas and
+// every regeneration serve the same bytes (issue #117).
+func TestAPKIndexDeterministic(t *testing.T) {
+	metas := apkFixture()
+
+	first := generateAPKIndex(metas)
+	time.Sleep(10 * time.Millisecond)
+	second := generateAPKIndex(metas)
+
+	if !bytes.Equal(first, second) {
+		t.Error("APKINDEX.tar.gz differs across generations")
+	}
+}
+
+// TestAPKIndexTarModTimePinned guards the tar header: its ModTime must be the
+// pinned Unix epoch, never wall clock. Fails if a future edit stamps time.Now().
+func TestAPKIndexTarModTimePinned(t *testing.T) {
+	metas := apkFixture()
+
+	zr, err := gzip.NewReader(bytes.NewReader(generateAPKIndex(metas)))
+	if err != nil {
+		t.Fatalf("gzip: %v", err)
+	}
+	if !zr.ModTime.IsZero() && zr.ModTime.Unix() != 0 {
+		t.Errorf("gzip header ModTime = %v, want zero/epoch", zr.ModTime)
+	}
+
+	tarBytes, err := io.ReadAll(zr)
+	if err != nil {
+		t.Fatalf("gunzip: %v", err)
+	}
+	tr := tar.NewReader(bytes.NewReader(tarBytes))
+	hdr, err := tr.Next()
+	if err != nil {
+		t.Fatalf("tar: %v", err)
+	}
+	if hdr.Name != "APKINDEX" {
+		t.Fatalf("tar entry = %q, want APKINDEX", hdr.Name)
+	}
+	if hdr.ModTime.Unix() != 0 {
+		t.Errorf("APKINDEX tar ModTime = %v (unix %d), want epoch (0)", hdr.ModTime, hdr.ModTime.Unix())
+	}
+}

internal/provider/alpine/alpine_local_test.go

@@ -0,0 +1,324 @@
+package alpine
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"context"
+	"crypto/sha1"
+	"encoding/base64"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+)
+
+type fakeBlobReader struct{ data []byte }
+
+func (f fakeBlobReader) Download(_ context.Context, _ string) (io.ReadCloser, int64, error) {
+	return io.NopCloser(bytes.NewReader(f.data)), int64(len(f.data)), nil
+}
+
+type errBlobReader struct{}
+
+func (errBlobReader) Download(_ context.Context, _ string) (io.ReadCloser, int64, error) {
+	return nil, 0, io.ErrUnexpectedEOF
+}
+
+// fakeAlpineStore satisfies provider.MetadataStore (shared) and
+// provider.AlpineMetadataStore, recording the row AfterUpload writes.
+type fakeAlpineStore struct{ inserted *provider.AlpineMetadata }
+
+func (f *fakeAlpineStore) InsertRPMMetadata(context.Context, *provider.RPMMetadata) error { return nil }
+func (f *fakeAlpineStore) InsertDebMetadata(context.Context, *provider.DebMetadata) error { return nil }
+func (f *fakeAlpineStore) InsertAlpineMetadata(_ context.Context, m *provider.AlpineMetadata) error {
+	f.inserted = m
+	return nil
+}
+
+// fakeAlpineDeleter satisfies provider.MetadataDeleter and AlpineMetadataDeleter.
+type fakeAlpineDeleter struct{ deleted bool }
+
+func (f *fakeAlpineDeleter) DeleteRPMMetadata(context.Context, string, string) error { return nil }
+func (f *fakeAlpineDeleter) DeleteDebMetadata(context.Context, string, string) error { return nil }
+func (f *fakeAlpineDeleter) DeleteAlpineMetadata(context.Context, string, string) error {
+	f.deleted = true
+	return nil
+}
+
+// fakeAlpineReader is a FileStore that also serves alpine metadata rows.
+type fakeAlpineReader struct{ metas []provider.AlpineMetadata }
+
+func (f fakeAlpineReader) ListAlpineMetadataEntries(context.Context, string) ([]provider.AlpineMetadata, error) {
+	return f.metas, nil
+}
+func (f fakeAlpineReader) ListFilesByPrefix(context.Context, string, string) ([]provider.FileEntry, error) {
+	return nil, nil
+}
+func (f fakeAlpineReader) ListPackages(context.Context, string) ([]string, error) { return nil, nil }
+
+type errAlpineReader struct{}
+
+func (errAlpineReader) ListAlpineMetadataEntries(context.Context, string) ([]provider.AlpineMetadata, error) {
+	return nil, io.ErrUnexpectedEOF
+}
+func (errAlpineReader) ListFilesByPrefix(context.Context, string, string) ([]provider.FileEntry, error) {
+	return nil, nil
+}
+func (errAlpineReader) ListPackages(context.Context, string) ([]string, error) { return nil, nil }
+
+func TestAlpineValidateUpload(t *testing.T) {
+	p := &Provider{}
+	sp, ct, err := p.ValidateUpload("x86_64/foo-1.0-r0.apk")
+	if err != nil || sp != "x86_64/foo-1.0-r0.apk" || ct != "application/vnd.android.package-archive" {
+		t.Errorf("sp=%q ct=%q err=%v", sp, ct, err)
+	}
+	// Dot-segment prefix is normalized away.
+	if sp, _, err := p.ValidateUpload("./aarch64/bar-2.0-r1.apk"); err != nil || sp != "aarch64/bar-2.0-r1.apk" {
+		t.Errorf("dot-seg: sp=%q err=%v", sp, err)
+	}
+	if _, _, err := p.ValidateUpload("foo.rpm"); err == nil {
+		t.Error("expected error for non-apk")
+	}
+	resp := p.UploadResponse("x86_64/foo-1.0-r0.apk", "sha256:abc", 42)
+	if resp["filename"] != "foo-1.0-r0.apk" || resp["content_hash"] != "sha256:abc" || resp["size_bytes"] != int64(42) {
+		t.Errorf("upload response %v", resp)
+	}
+}
+
+func TestAlpineAfterUpload(t *testing.T) {
+	data := testsupport.MinimalApk("hello", "1.0-r0", "x86_64")
+	store := &fakeAlpineStore{}
+	(&Provider{}).AfterUpload(context.Background(), "myrepo", "x86_64/hello-1.0-r0.apk",
+		"sha256:deadbeef", fakeBlobReader{data: data}, store)
+
+	m := store.inserted
+	if m == nil {
+		t.Fatal("no metadata inserted")
+	}
+	if m.Name != "hello" || m.Version != "1.0-r0" || m.Arch != "x86_64" {
+		t.Errorf("unexpected metadata: %+v", m)
+	}
+	if m.DownloadSize != int64(len(data)) {
+		t.Errorf("DownloadSize = %d, want %d", m.DownloadSize, len(data))
+	}
+	if m.InstalledSize != 4 {
+		t.Errorf("InstalledSize = %d, want 4", m.InstalledSize)
+	}
+	if m.License != "MIT" || m.Origin != "hello" || !strings.HasPrefix(m.Maintainer, "e2e") {
+		t.Errorf("scalar fields not parsed: %+v", m)
+	}
+	if len(m.Depends) != 1 || m.Depends[0] != "so:libc.musl-x86_64.so.1" {
+		t.Errorf("Depends = %v", m.Depends)
+	}
+	if len(m.Provides) != 1 || m.Provides[0] != "cmd:hello=1.0-r0" {
+		t.Errorf("Provides = %v", m.Provides)
+	}
+
+	// The Q1 checksum is the sha1 of the CONTROL gzip stream (the member whose
+	// tar carries .PKGINFO), not of the whole file.
+	controlRaw := controlStreamBytes(t, data)
+	sum := sha1.Sum(controlRaw)
+	want := "Q1" + base64.StdEncoding.EncodeToString(sum[:])
+	if m.Checksum != want {
+		t.Errorf("Checksum = %q, want %q (sha1 of control stream)", m.Checksum, want)
+	}
+	// And explicitly NOT the sha1 of the whole apk.
+	whole := sha1.Sum(data)
+	if m.Checksum == "Q1"+base64.StdEncoding.EncodeToString(whole[:]) {
+		t.Error("Checksum was computed over the whole file, not the control stream")
+	}
+}
+
+func TestAlpineAfterUploadErrors(t *testing.T) {
+	store := &fakeAlpineStore{}
+	(&Provider{}).AfterUpload(context.Background(), "r", "x86_64/p.apk", "sha256:x", errBlobReader{}, store)
+	if store.inserted != nil {
+		t.Error("no metadata should be inserted on download error")
+	}
+	store2 := &fakeAlpineStore{}
+	(&Provider{}).AfterUpload(context.Background(), "r", "x86_64/p.apk", "sha256:x", fakeBlobReader{data: []byte("not an apk")}, store2)
+	if store2.inserted != nil {
+		t.Error("no metadata should be inserted on parse error")
+	}
+}
+
+func TestAlpineAfterDelete(t *testing.T) {
+	d := &fakeAlpineDeleter{}
+	if err := (&Provider{}).AfterDelete(context.Background(), "r", "x86_64/p.apk", d); err != nil {
+		t.Fatalf("AfterDelete: %v", err)
+	}
+	if !d.deleted {
+		t.Error("DeleteAlpineMetadata not called")
+	}
+}
+
+func TestAlpineServeLocalIndex(t *testing.T) {
+	p := &Provider{}
+	reader := fakeAlpineReader{metas: []provider.AlpineMetadata{
+		{Name: "aaa", Version: "1.0-r0", Arch: "x86_64", Checksum: "Q1aaa", DownloadSize: 100, InstalledSize: 10,
+			Description: "pkg aaa", URL: "https://a", License: "MIT", Depends: []string{"so:libc"}, Provides: []string{"cmd:aaa"}},
+		{Name: "bbb", Version: "2.0-r0", Arch: "aarch64", Checksum: "Q1bbb", DownloadSize: 200, InstalledSize: 20},
+	}}
+
+	// x86_64 index contains only aaa, with its fields, and not bbb.
+	w := serveIndex(t, p, reader, "x86_64/APKINDEX.tar.gz")
+	if w.Code != 200 {
+		t.Fatalf("code %d", w.Code)
+	}
+	idx := untarIndex(t, w.Body.Bytes())
+	for _, want := range []string{"C:Q1aaa", "P:aaa", "V:1.0-r0", "A:x86_64", "S:100", "I:10", "T:pkg aaa", "U:https://a", "L:MIT", "D:so:libc", "p:cmd:aaa"} {
+		if !strings.Contains(idx, want) {
+			t.Errorf("x86_64 APKINDEX missing %q:\n%s", want, idx)
+		}
+	}
+	if strings.Contains(idx, "P:bbb") {
+		t.Errorf("x86_64 APKINDEX leaked aarch64 package:\n%s", idx)
+	}
+
+	// aarch64 index contains only bbb.
+	w = serveIndex(t, p, reader, "aarch64/APKINDEX.tar.gz")
+	idx = untarIndex(t, w.Body.Bytes())
+	if !strings.Contains(idx, "P:bbb") || strings.Contains(idx, "P:aaa") {
+		t.Errorf("aarch64 filtering wrong:\n%s", idx)
+	}
+
+	// Non-index and .apk paths are not owned by the indexer.
+	for _, path := range []string{"x86_64/foo-1.0-r0.apk", "x86_64/", "README"} {
+		w := httptest.NewRecorder()
+		r := httptest.NewRequest(http.MethodGet, "/"+path, nil)
+		if p.ServeLocalIndex(w, r, reader, "repo", path) {
+			t.Errorf("ServeLocalIndex should return false for %q", path)
+		}
+	}
+}
+
+// Empty fields are omitted from the record (bbb has no description/url).
+func TestAlpineIndexOmitsEmptyFields(t *testing.T) {
+	p := &Provider{}
+	reader := fakeAlpineReader{metas: []provider.AlpineMetadata{
+		{Name: "bbb", Version: "2.0-r0", Arch: "x86_64", Checksum: "Q1bbb", DownloadSize: 200, InstalledSize: 20},
+	}}
+	idx := untarIndex(t, serveIndex(t, p, reader, "x86_64/APKINDEX.tar.gz").Body.Bytes())
+	for _, absent := range []string{"T:", "U:", "L:", "D:", "p:", "i:", "o:", "m:", "c:", "k:"} {
+		if strings.Contains(idx, absent) {
+			t.Errorf("empty field %q should be omitted:\n%s", absent, idx)
+		}
+	}
+}
+
+// apk requests "./<arch>/APKINDEX.tar.gz" for a bare repo base URL; the
+// dot-segment must be collapsed and yield the same bytes as the plain path.
+func TestAlpineServeLocalIndexDotSegment(t *testing.T) {
+	p := &Provider{}
+	reader := fakeAlpineReader{metas: []provider.AlpineMetadata{
+		{Name: "aaa", Version: "1.0-r0", Arch: "x86_64", Checksum: "Q1aaa", DownloadSize: 100, InstalledSize: 10},
+	}}
+	plain := untarIndex(t, serveIndex(t, p, reader, "x86_64/APKINDEX.tar.gz").Body.Bytes())
+	dotted := untarIndex(t, serveIndex(t, p, reader, "./x86_64/APKINDEX.tar.gz").Body.Bytes())
+	if plain != dotted {
+		t.Errorf("dot-segment path differs:\nplain=%q\ndotted=%q", plain, dotted)
+	}
+}
+
+func TestAlpineServeLocalIndexArchRequired(t *testing.T) {
+	p := &Provider{}
+	reader := fakeAlpineReader{}
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest(http.MethodGet, "/APKINDEX.tar.gz", nil)
+	if !p.ServeLocalIndex(w, r, reader, "repo", "APKINDEX.tar.gz") {
+		t.Fatal("bare APKINDEX should be owned (and rejected) by the indexer")
+	}
+	if w.Code != http.StatusNotFound {
+		t.Errorf("bare APKINDEX code = %d, want 404", w.Code)
+	}
+}
+
+func TestAlpineServeMetadataError(t *testing.T) {
+	p := &Provider{}
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest(http.MethodGet, "/x86_64/APKINDEX.tar.gz", nil)
+	p.ServeLocalIndex(w, r, errAlpineReader{}, "repo", "x86_64/APKINDEX.tar.gz")
+	if w.Code != 500 {
+		t.Errorf("failing reader code = %d, want 500", w.Code)
+	}
+}
+
+func TestAlpineGenerateLocalIndexUnsupported(t *testing.T) {
+	if _, err := (&Provider{}).GenerateLocalIndex(context.Background(), fakeAlpineReader{}, "r", "x86_64/APKINDEX.tar.gz"); err == nil {
+		t.Error("expected unsupported error")
+	}
+}
+
+func serveIndex(t *testing.T, p *Provider, files provider.FileStore, path string) *httptest.ResponseRecorder {
+	t.Helper()
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest(http.MethodGet, "/"+path, nil)
+	if !p.ServeLocalIndex(w, r, files, "repo", path) {
+		t.Fatalf("ServeLocalIndex returned false for %q", path)
+	}
+	return w
+}
+
+// untarIndex un-gzips and un-tars an APKINDEX.tar.gz and returns the APKINDEX text.
+func untarIndex(t *testing.T, gzTar []byte) string {
+	t.Helper()
+	zr, err := gzip.NewReader(bytes.NewReader(gzTar))
+	if err != nil {
+		t.Fatalf("APKINDEX not gzip: %v", err)
+	}
+	tarBytes, _ := io.ReadAll(zr)
+	tr := tar.NewReader(bytes.NewReader(tarBytes))
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			t.Fatalf("APKINDEX not tar: %v", err)
+		}
+		if hdr.Name == "APKINDEX" {
+			b, _ := io.ReadAll(tr)
+			return string(b)
+		}
+	}
+	t.Fatal("no APKINDEX member in tarball")
+	return ""
+}
+
+// controlStreamBytes returns the raw bytes of the gzip stream whose tar carries
+// .PKGINFO, so the test can independently compute the expected Q1 checksum.
+func controlStreamBytes(t *testing.T, apk []byte) []byte {
+	t.Helper()
+	br := bytes.NewReader(apk)
+	zr, err := gzip.NewReader(br)
+	if err != nil {
+		t.Fatalf("gzip: %v", err)
+	}
+	prev := 0
+	for {
+		zr.Multistream(false)
+		out, _ := io.ReadAll(zr)
+		end := len(apk) - br.Len()
+		tr := tar.NewReader(bytes.NewReader(out))
+		for {
+			h, err := tr.Next()
+			if err != nil {
+				break
+			}
+			if strings.TrimPrefix(h.Name, "./") == ".PKGINFO" {
+				return apk[prev:end]
+			}
+		}
+		prev = end
+		if err := zr.Reset(br); err != nil {
+			break
+		}
+	}
+	t.Fatal("no control stream found")
+	return nil
+}

internal/provider/alpine/alpine_test.go

@@ -0,0 +1,60 @@
+package alpine
+
+import (
+	"context"
+	"testing"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+func TestType(t *testing.T) {
+	if (&Provider{}).Type() != models.PackageAlpine {
+		t.Fatal("wrong type")
+	}
+}
+
+func TestClassify(t *testing.T) {
+	p := &Provider{}
+	if p.Classify("v3.19/main/x86_64/APKINDEX.tar.gz") != provider.Mutable {
+		t.Error("APKINDEX should be mutable")
+	}
+	if p.Classify("v3.19/main/x86_64/curl-8.0-r0.apk") != provider.Immutable {
+		t.Error("apk should be immutable")
+	}
+}
+
+func TestContentType(t *testing.T) {
+	p := &Provider{}
+	cases := map[string]string{
+		"pkg.apk":          "application/vnd.android.package-archive",
+		"APKINDEX.tar.gz":  "application/gzip",
+		"something.random": "application/octet-stream",
+	}
+	for path, want := range cases {
+		if got := p.ContentType(path); got != want {
+			t.Errorf("ContentType(%q) = %q, want %q", path, got, want)
+		}
+	}
+}
+
+func TestUpstreamURL(t *testing.T) {
+	p := &Provider{}
+	got := p.UpstreamURL(models.Remote{BaseURL: "https://dl-cdn.alpinelinux.org/alpine/"}, "/v3.19/main/x86_64/curl.apk")
+	if got != "https://dl-cdn.alpinelinux.org/alpine/v3.19/main/x86_64/curl.apk" {
+		t.Errorf("got %q", got)
+	}
+}
+
+func TestRewriteResponse(t *testing.T) {
+	if out, err := (&Provider{}).RewriteResponse([]byte("x"), models.Remote{}, "http://proxy"); out != nil || err != nil {
+		t.Error("alpine never rewrites")
+	}
+}
+
+func TestAuthHeaders(t *testing.T) {
+	h, _ := (&Provider{}).AuthHeaders(context.Background(), models.Remote{Username: "u", Password: "p"})
+	if h.Get("Authorization") == "" {
+		t.Error("expected auth header")
+	}
+}

internal/provider/alpine/github.go

@@ -0,0 +1,714 @@
+package alpine
+
+import (
+	"bytes"
+	"compress/gzip"
+	"context"
+	"crypto/sha1"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"git.unkin.net/unkin/artifactapi/internal/githubauth"
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// gitHubProvider is the process-wide singleton for github_alpine. The background
+// Syncer binds its shared rate limiter and work queue onto this instance so the
+// request path and the syncer drive the same derive machinery.
+var gitHubProvider = newGitHubProvider()
+
+func init() {
+	provider.Register(gitHubProvider)
+}
+
+// Tuning knobs for the no-precache control fetch. An .apk is up to three
+// concatenated gzip streams (optional signature, control, data); the control
+// stream carrying .PKGINFO sits near the front, so a small prefix reliably
+// covers it.
+const (
+	defaultHeaderRangeInitial = 32 << 10 // 32 KiB — covers the control stream of almost every .apk
+	defaultHeaderRangeMax     = 16 << 20 // 16 MiB — give up past this and skip the asset
+	defaultReleasePageCap     = 10       // 100 releases/page * 10 pages
+
+	defaultScanTimeout  = 10 * time.Minute
+	defaultServeTimeout = 30 * time.Second
+	defaultColdWait     = 8 * time.Second
+)
+
+// GitHubProvider is a metadata-only remote: it scans a GitHub repo's releases
+// for .apk assets, derives per-asset .PKGINFO metadata via a ranged prefix fetch
+// (never downloading whole packages), synthesizes a per-arch APKINDEX from that
+// cached metadata, and redirects package downloads to a backend "releases_remote"
+// (the generic github.com remote) that serves the actual bytes.
+type GitHubProvider struct {
+	client *http.Client
+
+	headerInitial int64
+	headerMax     int64
+	pageCap       int
+	scanTimeout   time.Duration
+	serveTimeout  time.Duration
+	coldWait      time.Duration
+
+	limiter *rate.Limiter
+	syncer  *Syncer
+
+	serverCred githubauth.Credential
+
+	mu       sync.Mutex
+	scanning map[string]bool
+	lastScan map[string]time.Time
+}
+
+func newGitHubProvider() *GitHubProvider {
+	return &GitHubProvider{
+		client:        &http.Client{},
+		headerInitial: defaultHeaderRangeInitial,
+		headerMax:     defaultHeaderRangeMax,
+		pageCap:       defaultReleasePageCap,
+		scanTimeout:   defaultScanTimeout,
+		serveTimeout:  defaultServeTimeout,
+		coldWait:      defaultColdWait,
+		scanning:      map[string]bool{},
+		lastScan:      map[string]time.Time{},
+	}
+}
+
+func (p *GitHubProvider) limiterWait(ctx context.Context) error {
+	if p.limiter == nil {
+		return nil
+	}
+	return p.limiter.Wait(ctx)
+}
+
+func (p *GitHubProvider) Type() models.PackageType { return models.PackageGitHubAlpine }
+
+func (p *GitHubProvider) Classify(path string) provider.Mutability {
+	if strings.HasSuffix(path, "APKINDEX.tar.gz") {
+		return provider.Mutable
+	}
+	return provider.Immutable
+}
+
+func (p *GitHubProvider) ContentType(path string) string {
+	switch {
+	case strings.HasSuffix(path, ".apk"):
+		return "application/vnd.android.package-archive"
+	case strings.HasSuffix(path, ".tar.gz"):
+		return "application/gzip"
+	}
+	return "application/octet-stream"
+}
+
+func (p *GitHubProvider) UpstreamURL(remote models.Remote, path string) string {
+	return strings.TrimRight(remote.BaseURL, "/") + "/" + strings.TrimLeft(path, "/")
+}
+
+func (p *GitHubProvider) RewriteResponse(_ []byte, _ models.Remote, _ string) ([]byte, error) {
+	return nil, nil
+}
+
+func (p *GitHubProvider) AuthHeaders(ctx context.Context, remote models.Remote) (http.Header, error) {
+	return p.githubHeaders(ctx, remote, false)
+}
+
+// ServeRemote answers a request against a github_alpine remote. It refreshes the
+// derived metadata (bounded by mutable_ttl), serves a synthesized per-arch
+// APKINDEX.tar.gz, and 302-redirects .apk downloads to the backend
+// releases_remote. Returns false only for paths it does not own.
+func (p *GitHubProvider) ServeRemote(w http.ResponseWriter, r *http.Request, remote models.Remote, reqPath, proxyBaseURL string, store provider.RemoteMetadataStore) bool {
+	p.onRequest(remote, store)
+
+	// apk requests the index at "./<arch>/APKINDEX.tar.gz"; collapse the
+	// dot-segment before matching, mirroring the local indexer.
+	path := normalizeIndexPath(reqPath)
+
+	if strings.HasSuffix(path, "APKINDEX.tar.gz") {
+		p.serveIndex(w, r, remote, path, store)
+		return true
+	}
+
+	if strings.HasSuffix(path, ".apk") {
+		if remote.ReleasesRemote == "" {
+			http.Error(w, "github_alpine remote has no releases_remote configured for downloads", http.StatusInternalServerError)
+			return true
+		}
+		p.serveApkRedirect(w, r, remote, path, proxyBaseURL, store)
+		return true
+	}
+
+	return false
+}
+
+// serveApkRedirect resolves an apk-reconstructed download path — apk builds
+// "<arch>/<name>-<version>.apk" itself because APKINDEX carries no filename — to
+// the real github-relative asset path stored on the metadata row, then redirects
+// to the backend releases_remote. Passing the inbound path through verbatim would
+// point at a nonexistent, allowlist-denied github.com path.
+func (p *GitHubProvider) serveApkRedirect(w http.ResponseWriter, r *http.Request, remote models.Remote, path, proxyBaseURL string, store provider.RemoteMetadataStore) {
+	arch := strings.TrimSuffix(path[:strings.LastIndex(path, "/")+1], "/")
+	basename := path[strings.LastIndex(path, "/")+1:]
+	if arch == "" || strings.Contains(arch, "/") {
+		http.Error(w, "apk download must be requested per-arch: <arch>/<name>-<version>.apk", http.StatusNotFound)
+		return
+	}
+
+	reader, ok := store.(provider.AlpineMetadataReader)
+	if !ok {
+		http.Error(w, "alpine metadata not available", http.StatusInternalServerError)
+		return
+	}
+	sctx, cancel := context.WithTimeout(context.WithoutCancel(r.Context()), p.serveTimeout)
+	defer cancel()
+	rows, err := reader.ListAlpineMetadataEntries(sctx, remote.Name)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	for _, row := range rows {
+		if row.Arch == arch && row.Name+"-"+row.Version+".apk" == basename {
+			loc := strings.TrimRight(proxyBaseURL, "/") + "/api/v1/remote/" + remote.ReleasesRemote + "/" + strings.TrimLeft(row.FilePath, "/")
+			http.Redirect(w, r, loc, http.StatusFound)
+			return
+		}
+	}
+	http.Error(w, "package not found", http.StatusNotFound)
+}
+
+func (p *GitHubProvider) serveIndex(w http.ResponseWriter, r *http.Request, remote models.Remote, path string, store provider.RemoteMetadataStore) {
+	arch := strings.TrimSuffix(path, "APKINDEX.tar.gz")
+	arch = strings.Trim(arch, "/")
+	if arch == "" || strings.Contains(arch, "/") {
+		http.Error(w, "APKINDEX must be requested per-arch: <arch>/APKINDEX.tar.gz", http.StatusNotFound)
+		return
+	}
+
+	// Serve on a context detached from the inbound request so a client disconnect
+	// never cancels the metadata DB read and surfaces as a 500.
+	sctx, cancel := context.WithTimeout(context.WithoutCancel(r.Context()), p.serveTimeout)
+	defer cancel()
+
+	if p.syncer != nil && !p.ensurePrimed(sctx, remote, store) {
+		w.Header().Set("Retry-After", "5")
+		http.Error(w, "metadata is being prepared, retry shortly", http.StatusServiceUnavailable)
+		return
+	}
+
+	reader, ok := store.(provider.AlpineMetadataReader)
+	if !ok {
+		http.Error(w, "alpine metadata not available", http.StatusInternalServerError)
+		return
+	}
+	metas, err := reader.ListAlpineMetadataEntries(sctx, remote.Name)
+	if err != nil {
+		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+			http.Error(w, "metadata read canceled", http.StatusServiceUnavailable)
+			return
+		}
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	var filtered []provider.AlpineMetadata
+	for _, m := range metas {
+		if m.Arch == arch {
+			filtered = append(filtered, m)
+		}
+	}
+
+	w.Header().Set("Content-Type", "application/gzip")
+	w.WriteHeader(http.StatusOK)
+	w.Write(generateAPKIndex(filtered))
+}
+
+// onRequest keeps a remote's derived metadata fresh off the request path.
+func (p *GitHubProvider) onRequest(remote models.Remote, store provider.RemoteMetadataStore) {
+	if p.syncer != nil {
+		p.syncer.enqueue(remote, false)
+		return
+	}
+	p.refresh(remote, store)
+}
+
+// ensurePrimed returns true once the remote has at least one cached row. On an
+// empty cache it enqueues a prime and polls briefly for it to land.
+func (p *GitHubProvider) ensurePrimed(ctx context.Context, remote models.Remote, store provider.RemoteMetadataStore) bool {
+	if !p.cacheEmpty(ctx, store, remote.Name) {
+		return true
+	}
+	if p.syncer != nil {
+		p.syncer.enqueue(remote, true)
+	}
+
+	deadline := time.Now().Add(p.coldWait)
+	for time.Now().Before(deadline) {
+		select {
+		case <-ctx.Done():
+			return false
+		case <-time.After(400 * time.Millisecond):
+		}
+		if !p.cacheEmpty(ctx, store, remote.Name) {
+			return true
+		}
+	}
+	return false
+}
+
+func (p *GitHubProvider) cacheEmpty(ctx context.Context, store provider.RemoteMetadataStore, name string) bool {
+	reader, ok := store.(provider.AlpineMetadataReader)
+	if !ok {
+		return false
+	}
+	rows, err := reader.ListAlpineMetadataEntries(ctx, name)
+	if err != nil {
+		return false
+	}
+	return len(rows) == 0
+}
+
+// refresh brings the derived metadata up to date without coupling the scan to
+// the inbound request (legacy inline path used without a syncer / in unit tests).
+func (p *GitHubProvider) refresh(remote models.Remote, store provider.RemoteMetadataStore) {
+	ttl := time.Duration(remote.MutableTTL) * time.Second
+	if ttl <= 0 {
+		ttl = 5 * time.Minute
+	}
+
+	p.mu.Lock()
+	last, ok := p.lastScan[remote.Name]
+	fresh := ok && time.Since(last) < ttl
+	if fresh || p.scanning[remote.Name] {
+		p.mu.Unlock()
+		return
+	}
+	p.scanning[remote.Name] = true
+	p.mu.Unlock()
+
+	if p.cacheEmpty(context.Background(), store, remote.Name) {
+		p.runScan(remote, store)
+		return
+	}
+	go p.runScan(remote, store)
+}
+
+func (p *GitHubProvider) runScan(remote models.Remote, store provider.RemoteMetadataStore) {
+	defer func() {
+		p.mu.Lock()
+		delete(p.scanning, remote.Name)
+		p.mu.Unlock()
+	}()
+
+	ctx, cancel := context.WithTimeout(context.Background(), p.scanTimeout)
+	defer cancel()
+
+	if err := p.scan(ctx, remote, store); err != nil {
+		slog.Error("github_alpine: release scan failed", "remote", remote.Name, "error", err)
+		return
+	}
+
+	p.mu.Lock()
+	p.lastScan[remote.Name] = time.Now()
+	p.mu.Unlock()
+}
+
+// scan runs a full unconditional derive. Retained for the legacy inline refresh
+// path and existing tests; the syncer uses scanWithState.
+func (p *GitHubProvider) scan(ctx context.Context, remote models.Remote, store provider.RemoteMetadataStore) error {
+	_, _, err := p.scanWithState(ctx, remote, store, "")
+	return err
+}
+
+// scanWithState derives metadata incrementally. It sends the prior releases-list
+// ETag as a conditional request: a 304 means nothing changed. On a 200 it diffs
+// the release assets against the cache, derives only new/changed assets, prunes
+// assets that disappeared, and returns the new ETag.
+func (p *GitHubProvider) scanWithState(ctx context.Context, remote models.Remote, store provider.RemoteMetadataStore, etag string) (newEtag string, changed bool, err error) {
+	inserter, ok := store.(provider.AlpineMetadataStore)
+	if !ok {
+		return etag, false, errors.New("store does not support alpine metadata writes")
+	}
+	deleter, ok := store.(provider.AlpineMetadataDeleter)
+	if !ok {
+		return etag, false, errors.New("store does not support alpine metadata deletes")
+	}
+	reader, ok := store.(provider.AlpineMetadataReader)
+	if !ok {
+		return etag, false, errors.New("store does not support alpine metadata reads")
+	}
+
+	releases, newEtag, notModified, err := p.fetchReleases(ctx, remote, etag)
+	if err != nil {
+		return etag, false, err
+	}
+	if notModified {
+		return etag, false, nil
+	}
+
+	existing, err := reader.ListAlpineMetadataEntries(ctx, remote.Name)
+	if err != nil {
+		return newEtag, false, err
+	}
+	existingByPath := make(map[string]provider.AlpineMetadata, len(existing))
+	for _, m := range existing {
+		existingByPath[m.FilePath] = m
+	}
+
+	allow, err := compilePatterns(remote.Patterns)
+	if err != nil {
+		return newEtag, false, err
+	}
+
+	seen := map[string]bool{}
+	for _, rel := range releases {
+		if rel.Draft {
+			continue
+		}
+		for _, asset := range rel.Assets {
+			if !strings.HasSuffix(strings.ToLower(asset.Name), ".apk") {
+				continue
+			}
+			if !matchesAny(allow, asset.Name) {
+				continue
+			}
+			fp := assetPath(asset)
+			if fp == "" {
+				continue
+			}
+			seen[fp] = true
+
+			if cur, ok := existingByPath[fp]; ok {
+				if asset.Digest == "" || cur.ContentHash == asset.Digest {
+					continue
+				}
+				_ = deleter.DeleteAlpineMetadata(ctx, remote.Name, fp)
+			}
+
+			meta, err := p.deriveAsset(ctx, remote, asset, fp)
+			if err != nil {
+				slog.Warn("github_alpine: derive asset failed", "remote", remote.Name, "asset", asset.Name, "error", err)
+				continue
+			}
+			if err := inserter.InsertAlpineMetadata(ctx, meta); err != nil {
+				slog.Error("github_alpine: insert metadata failed", "remote", remote.Name, "asset", asset.Name, "error", err)
+				continue
+			}
+			slog.Info("github_alpine: derived asset", "remote", remote.Name, "name", meta.Name, "version", meta.Version, "arch", meta.Arch)
+		}
+	}
+
+	for fp := range existingByPath {
+		if !seen[fp] {
+			_ = deleter.DeleteAlpineMetadata(ctx, remote.Name, fp)
+		}
+	}
+	return newEtag, true, nil
+}
+
+type ghRelease struct {
+	TagName string    `json:"tag_name"`
+	Draft   bool      `json:"draft"`
+	Assets  []ghAsset `json:"assets"`
+}
+
+type ghAsset struct {
+	Name               string `json:"name"`
+	Size               int64  `json:"size"`
+	BrowserDownloadURL string `json:"browser_download_url"`
+	Digest             string `json:"digest"`
+}
+
+// fetchReleases lists a repo's releases, sending the prior ETag as If-None-Match
+// on page 1 so an unchanged repo short-circuits to notModified. Every call waits
+// on the shared limiter first.
+func (p *GitHubProvider) fetchReleases(ctx context.Context, remote models.Remote, etag string) (all []ghRelease, newEtag string, notModified bool, err error) {
+	base := strings.TrimRight(remote.BaseURL, "/") + "/releases"
+	for page := 1; page <= p.pageCap; page++ {
+		u := fmt.Sprintf("%s?per_page=100&page=%d", base, page)
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
+		if err != nil {
+			return nil, "", false, err
+		}
+		hdr, err := p.githubHeaders(ctx, remote, true)
+		if err != nil {
+			return nil, "", false, err
+		}
+		copyHeaders(req, hdr)
+		if page == 1 && etag != "" {
+			req.Header.Set("If-None-Match", etag)
+		}
+
+		if err := p.limiterWait(ctx); err != nil {
+			return nil, "", false, err
+		}
+		resp, err := p.client.Do(req)
+		if err != nil {
+			return nil, "", false, err
+		}
+		if page == 1 && resp.StatusCode == http.StatusNotModified {
+			io.Copy(io.Discard, resp.Body)
+			resp.Body.Close()
+			return nil, etag, true, nil
+		}
+		body, err := io.ReadAll(resp.Body)
+		respEtag := resp.Header.Get("ETag")
+		resp.Body.Close()
+		if err != nil {
+			return nil, "", false, err
+		}
+		if resp.StatusCode != http.StatusOK {
+			return nil, "", false, fmt.Errorf("github releases API %s: status %d", u, resp.StatusCode)
+		}
+		if page == 1 {
+			newEtag = respEtag
+		}
+		var releases []ghRelease
+		if err := json.Unmarshal(body, &releases); err != nil {
+			return nil, "", false, fmt.Errorf("decode releases: %w", err)
+		}
+		if len(releases) == 0 {
+			break
+		}
+		all = append(all, releases...)
+		if len(releases) < 100 {
+			break
+		}
+	}
+	return all, newEtag, false, nil
+}
+
+func (p *GitHubProvider) deriveAsset(ctx context.Context, remote models.Remote, asset ghAsset, fp string) (*provider.AlpineMetadata, error) {
+	meta, err := p.fetchPkginfo(ctx, remote, asset.BrowserDownloadURL)
+	if err != nil {
+		return nil, err
+	}
+	if meta.Name == "" || meta.Arch == "" {
+		return nil, errors.New(".PKGINFO missing pkgname/arch")
+	}
+
+	meta.RepoName = remote.Name
+	meta.FilePath = fp
+	// S: the on-disk .apk size comes straight from the releases API, so we never
+	// download the body just to size it.
+	meta.DownloadSize = asset.Size
+	// ContentHash records the GitHub asset digest (when present) purely so the
+	// next scan can detect a changed asset; unlike deb it is not the index
+	// checksum (that is the Q1 control-stream sum already set in fetchPkginfo).
+	if asset.Digest != "" {
+		meta.ContentHash = asset.Digest
+	}
+	return meta, nil
+}
+
+// fetchPkginfo pulls only the front of the .apk with a ranged GET and derives the
+// .PKGINFO fields plus the apk pull checksum (C: = Q1 + base64(sha1(control gzip
+// stream))). The control stream sits near the front, so a small prefix suffices;
+// a prefix that truncates it doubles the range and retries.
+func (p *GitHubProvider) fetchPkginfo(ctx context.Context, remote models.Remote, downloadURL string) (*provider.AlpineMetadata, error) {
+	n := p.headerInitial
+	for {
+		body, full, err := p.rangeGet(ctx, remote, downloadURL, n)
+		if err != nil {
+			return nil, err
+		}
+		meta, complete, perr := pkginfoFromPrefix(body)
+		if perr != nil {
+			return nil, fmt.Errorf("parse apk .PKGINFO: %w", perr)
+		}
+		if complete {
+			return meta, nil
+		}
+		if full || n >= p.headerMax {
+			return nil, fmt.Errorf(".PKGINFO not found within %d bytes of %s", n, downloadURL)
+		}
+		n *= 2
+		if n > p.headerMax {
+			n = p.headerMax
+		}
+	}
+}
+
+// pkginfoFromPrefix parses the concatenated gzip streams present in a front
+// prefix of an .apk. It walks each fully-covered gzip member until it finds the
+// control stream (the one whose tar carries .PKGINFO), computes the Q1 pull
+// checksum from that stream's raw bytes, and reads the .PKGINFO fields. A prefix
+// too short to fully cover the control stream returns complete=false so the
+// caller can widen the range.
+func pkginfoFromPrefix(prefix []byte) (meta *provider.AlpineMetadata, complete bool, err error) {
+	br := bytes.NewReader(prefix)
+	zr, zerr := gzip.NewReader(br)
+	if zerr != nil {
+		if zerr == io.EOF || zerr == io.ErrUnexpectedEOF {
+			return nil, false, nil
+		}
+		return nil, false, zerr
+	}
+	prev := 0
+	for {
+		zr.Multistream(false)
+		out, rerr := io.ReadAll(zr)
+		if rerr != nil {
+			// A member truncated by the range boundary is not an error — widen.
+			if rerr == io.ErrUnexpectedEOF || rerr == io.EOF {
+				return nil, false, nil
+			}
+			return nil, false, rerr
+		}
+		end := len(prefix) - br.Len()
+		raw := prefix[prev:end]
+
+		if pkginfo, ok := pkginfoFromTar(out); ok {
+			m := parsePkginfo(pkginfo)
+			sum := sha1.Sum(raw)
+			m.Checksum = "Q1" + base64.StdEncoding.EncodeToString(sum[:])
+			return m, true, nil
+		}
+
+		prev = end
+		if rsterr := zr.Reset(br); rsterr != nil {
+			if rsterr == io.EOF {
+				// No more complete members in the prefix; the control stream is
+				// either not covered yet or genuinely absent — let the caller
+				// decide by widening (or hitting the full-object guard).
+				return nil, false, nil
+			}
+			if rsterr == io.ErrUnexpectedEOF {
+				return nil, false, nil
+			}
+			return nil, false, rsterr
+		}
+	}
+}
+
+// rangeGet returns the first n bytes of downloadURL. full is true when the
+// response body was shorter than n (i.e. we already have the whole object).
+func (p *GitHubProvider) rangeGet(ctx context.Context, remote models.Remote, downloadURL string, n int64) ([]byte, bool, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, downloadURL, nil)
+	if err != nil {
+		return nil, false, err
+	}
+	hdr, err := p.githubHeaders(ctx, remote, false)
+	if err != nil {
+		return nil, false, err
+	}
+	copyHeaders(req, hdr)
+	req.Header.Set("Range", fmt.Sprintf("bytes=0-%d", n-1))
+
+	if err := p.limiterWait(ctx); err != nil {
+		return nil, false, err
+	}
+	resp, err := p.client.Do(req)
+	if err != nil {
+		return nil, false, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusPartialContent {
+		return nil, false, fmt.Errorf("range GET %s: status %d", downloadURL, resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(io.LimitReader(resp.Body, n))
+	if err != nil {
+		return nil, false, err
+	}
+	full := int64(len(body)) < n
+	return body, full, nil
+}
+
+// assetPath is the package's location relative to github.com — the path the
+// backend releases_remote (base https://github.com) proxies. It doubles as the
+// alpine_metadata key and the redirect target, so an .apk download resolves back
+// to this remote and redirects to the backend.
+func assetPath(asset ghAsset) string {
+	u, err := url.Parse(asset.BrowserDownloadURL)
+	if err != nil {
+		return ""
+	}
+	return strings.TrimPrefix(u.Path, "/")
+}
+
+// githubHeaders builds the outbound headers for a GitHub request, attaching a
+// bearer credential when one is available. A per-remote credential wins; absent
+// that, the process-wide server credential is used; absent both, the request is
+// unauthenticated.
+func (p *GitHubProvider) githubHeaders(ctx context.Context, remote models.Remote, api bool) (http.Header, error) {
+	h := http.Header{}
+	if api {
+		h.Set("Accept", "application/vnd.github+json")
+		h.Set("X-GitHub-Api-Version", "2022-11-28")
+	}
+	tok, err := p.githubToken(ctx, remote)
+	if err != nil {
+		return nil, err
+	}
+	if tok != "" {
+		h.Set("Authorization", "Bearer "+tok)
+	}
+	return h, nil
+}
+
+// githubToken resolves the bearer token for a remote. Precedence: a per-remote
+// credential (password, then username) overrides the server credential.
+func (p *GitHubProvider) githubToken(ctx context.Context, remote models.Remote) (string, error) {
+	if remote.Password != "" {
+		return remote.Password, nil
+	}
+	if remote.Username != "" {
+		return remote.Username, nil
+	}
+	if c := p.serverCredential(); c != nil {
+		return c.Token(ctx)
+	}
+	return "", nil
+}
+
+func (p *GitHubProvider) serverCredential() githubauth.Credential {
+	if p.serverCred != nil {
+		return p.serverCred
+	}
+	return githubauth.Server()
+}
+
+func copyHeaders(req *http.Request, h http.Header) {
+	for k, vals := range h {
+		for _, v := range vals {
+			req.Header.Add(k, v)
+		}
+	}
+}
+
+func compilePatterns(patterns []string) ([]*regexp.Regexp, error) {
+	var out []*regexp.Regexp
+	for _, p := range patterns {
+		re, err := regexp.Compile(p)
+		if err != nil {
+			return nil, fmt.Errorf("invalid pattern %q: %w", p, err)
+		}
+		out = append(out, re)
+	}
+	return out, nil
+}
+
+func matchesAny(res []*regexp.Regexp, s string) bool {
+	if len(res) == 0 {
+		return true
+	}
+	for _, re := range res {
+		if re.MatchString(s) {
+			return true
+		}
+	}
+	return false
+}

internal/provider/alpine/github_test.go

@@ -0,0 +1,497 @@
+package alpine
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// fakeStore is an in-memory provider.RemoteMetadataStore + AlpineMetadata
+// store/reader/deleter keyed by file_path, mirroring the (repo_name, file_path)
+// uniqueness of the real alpine_metadata table.
+type fakeStore struct {
+	mu   sync.Mutex
+	rows map[string]provider.AlpineMetadata
+}
+
+func newFakeStore() *fakeStore { return &fakeStore{rows: map[string]provider.AlpineMetadata{}} }
+
+func (f *fakeStore) InsertAlpineMetadata(_ context.Context, m *provider.AlpineMetadata) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if _, ok := f.rows[m.FilePath]; ok {
+		return nil // ON CONFLICT DO NOTHING
+	}
+	f.rows[m.FilePath] = *m
+	return nil
+}
+
+func (f *fakeStore) DeleteAlpineMetadata(_ context.Context, _, filePath string) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	delete(f.rows, filePath)
+	return nil
+}
+
+func (f *fakeStore) ListAlpineMetadataEntries(ctx context.Context, _ string) ([]provider.AlpineMetadata, error) {
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	out := make([]provider.AlpineMetadata, 0, len(f.rows))
+	for _, m := range f.rows {
+		out = append(out, m)
+	}
+	return out, nil
+}
+
+// The generic RemoteMetadataStore surface (rpm/deb) is unused by the alpine
+// github provider but required to satisfy the interface passed to ServeRemote.
+func (f *fakeStore) InsertRPMMetadata(context.Context, *provider.RPMMetadata) error { return nil }
+func (f *fakeStore) DeleteRPMMetadata(context.Context, string, string) error        { return nil }
+func (f *fakeStore) ListRPMMetadataEntries(context.Context, string) ([]provider.RPMMetadata, error) {
+	return nil, nil
+}
+func (f *fakeStore) InsertDebMetadata(context.Context, *provider.DebMetadata) error { return nil }
+func (f *fakeStore) DeleteDebMetadata(context.Context, string, string) error        { return nil }
+
+var _ provider.RemoteMetadataStore = (*fakeStore)(nil)
+
+// githubFixture serves the releases API and the .apk asset downloads (with Range
+// support) for a set of packages. digest controls whether the asset carries a
+// sha256 digest (change-detection path) or not.
+type githubFixture struct {
+	srv         *httptest.Server
+	apkBytes    map[string][]byte
+	rangeHit    map[string]int
+	fullHit     map[string]int
+	etag        string
+	releasesHit int
+	notModHit   int
+	releaseAuth string
+	assetAuth   string
+	mu          sync.Mutex
+}
+
+func newGitHubFixture(t *testing.T, withDigest bool) *githubFixture {
+	t.Helper()
+	f := &githubFixture{
+		apkBytes: map[string][]byte{},
+		rangeHit: map[string]int{},
+		fullHit:  map[string]int{},
+	}
+	f.apkBytes["demo-1.2.3-r0.apk"] = testsupport.MinimalApk("demo", "1.2.3-r0", "x86_64")
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/repos/acme/tools/releases", func(w http.ResponseWriter, r *http.Request) {
+		page := r.URL.Query().Get("page")
+		if page != "" && page != "1" {
+			w.Write([]byte("[]"))
+			return
+		}
+		f.mu.Lock()
+		f.releasesHit++
+		f.releaseAuth = r.Header.Get("Authorization")
+		etag := f.etag
+		if etag != "" && r.Header.Get("If-None-Match") == etag {
+			f.notModHit++
+			f.mu.Unlock()
+			w.WriteHeader(http.StatusNotModified)
+			return
+		}
+		f.mu.Unlock()
+		if etag != "" {
+			w.Header().Set("ETag", etag)
+		}
+		var assets []map[string]any
+		for name := range f.apkBytes {
+			a := map[string]any{
+				"name":                 name,
+				"size":                 len(f.apkBytes[name]),
+				"browser_download_url": f.srv.URL + "/acme/tools/releases/download/v1.2.3/" + name,
+			}
+			if withDigest {
+				sum := sha256.Sum256(f.apkBytes[name])
+				a["digest"] = "sha256:" + hex.EncodeToString(sum[:])
+			}
+			assets = append(assets, a)
+		}
+		rel := []map[string]any{{"tag_name": "v1.2.3", "draft": false, "assets": assets}}
+		json.NewEncoder(w).Encode(rel)
+	})
+	mux.HandleFunc("/acme/tools/releases/download/", func(w http.ResponseWriter, r *http.Request) {
+		name := r.URL.Path[strings.LastIndex(r.URL.Path, "/")+1:]
+		body, ok := f.apkBytes[name]
+		if !ok {
+			http.Error(w, "not found", 404)
+			return
+		}
+		rng := r.Header.Get("Range")
+		f.mu.Lock()
+		f.assetAuth = r.Header.Get("Authorization")
+		if rng != "" {
+			f.rangeHit[name]++
+		} else {
+			f.fullHit[name]++
+		}
+		f.mu.Unlock()
+
+		if rng == "" {
+			w.WriteHeader(200)
+			w.Write(body)
+			return
+		}
+		var end int
+		fmt.Sscanf(rng, "bytes=0-%d", &end)
+		if end >= len(body)-1 {
+			end = len(body) - 1
+		}
+		w.Header().Set("Content-Range", fmt.Sprintf("bytes 0-%d/%d", end, len(body)))
+		w.Header().Set("Content-Length", strconv.Itoa(end+1))
+		w.WriteHeader(http.StatusPartialContent)
+		w.Write(body[:end+1])
+	})
+	f.srv = httptest.NewServer(mux)
+	t.Cleanup(f.srv.Close)
+	return f
+}
+
+func (f *githubFixture) remote() models.Remote {
+	return models.Remote{
+		Name:           "acme-apk",
+		PackageType:    models.PackageGitHubAlpine,
+		BaseURL:        f.srv.URL + "/repos/acme/tools",
+		ReleasesRemote: "github",
+		MutableTTL:     3600,
+	}
+}
+
+func newTestProvider() *GitHubProvider {
+	p := newGitHubProvider()
+	p.headerInitial = 32 // force the ranged-fetch retry loop against the tiny fixture
+	p.headerMax = 1 << 20
+	return p
+}
+
+const demoPath = "acme/tools/releases/download/v1.2.3/demo-1.2.3-r0.apk"
+
+func TestGitHubScanDerivesPkginfoFromPrefix(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+
+	if err := p.scan(context.Background(), fx.remote(), store); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+
+	metas, _ := store.ListAlpineMetadataEntries(context.Background(), "acme-apk")
+	if len(metas) != 1 {
+		t.Fatalf("want 1 metadata row, got %d", len(metas))
+	}
+	m := metas[0]
+	if m.Name != "demo" || m.Version != "1.2.3-r0" || m.Arch != "x86_64" {
+		t.Fatalf("bad .PKGINFO fields: %+v", m)
+	}
+	if m.FilePath != demoPath {
+		t.Fatalf("FilePath = %q, want %q", m.FilePath, demoPath)
+	}
+	if int(m.DownloadSize) != len(fx.apkBytes["demo-1.2.3-r0.apk"]) {
+		t.Fatalf("DownloadSize = %d, want %d", m.DownloadSize, len(fx.apkBytes["demo-1.2.3-r0.apk"]))
+	}
+	if !strings.HasPrefix(m.Checksum, "Q1") {
+		t.Fatalf("Checksum not a Q1 pull checksum: %q", m.Checksum)
+	}
+	// The C: checksum must equal Q1 over the raw control gzip stream, matching the
+	// local-upload parser applied to the same bytes.
+	want, err := parseApk(fx.apkBytes["demo-1.2.3-r0.apk"])
+	if err != nil {
+		t.Fatalf("reference parseApk: %v", err)
+	}
+	if m.Checksum != want.Checksum {
+		t.Fatalf("Checksum = %q, want %q (Q1 of control stream)", m.Checksum, want.Checksum)
+	}
+	if fx.fullHit["demo-1.2.3-r0.apk"] != 0 {
+		t.Fatalf("expected no full download, got %d", fx.fullHit["demo-1.2.3-r0.apk"])
+	}
+	if fx.rangeHit["demo-1.2.3-r0.apk"] == 0 {
+		t.Fatalf("expected ranged .PKGINFO fetch")
+	}
+}
+
+func TestGitHubServeRemoteIndexAndRedirect(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+	const proxyBase = "https://artifactapi.example"
+
+	// The per-arch index is served and triggers the initial scan.
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-apk/x86_64/APKINDEX.tar.gz", nil)
+	if !p.ServeRemote(rec, req, remote, "x86_64/APKINDEX.tar.gz", proxyBase, store) {
+		t.Fatal("ServeRemote did not handle APKINDEX")
+	}
+	if rec.Code != 200 {
+		t.Fatalf("APKINDEX bad: code=%d body=%s", rec.Code, rec.Body.String())
+	}
+	idx := readAPKIndex(t, rec.Body.Bytes())
+	if !strings.Contains(idx, "P:demo") || !strings.Contains(idx, "A:x86_64") {
+		t.Fatalf("APKINDEX missing package record: %s", idx)
+	}
+	if !strings.Contains(idx, "C:Q1") {
+		t.Fatalf("APKINDEX missing pull checksum: %s", idx)
+	}
+
+	// A different arch yields an empty (but valid) index.
+	rec = httptest.NewRecorder()
+	req = httptest.NewRequest(http.MethodGet, "/x", nil)
+	if !p.ServeRemote(rec, req, remote, "aarch64/APKINDEX.tar.gz", proxyBase, store) {
+		t.Fatal("ServeRemote did not handle aarch64 APKINDEX")
+	}
+	if rec.Code != 200 {
+		t.Fatalf("empty-arch index bad: %d", rec.Code)
+	}
+	if got := readAPKIndex(t, rec.Body.Bytes()); strings.Contains(got, "P:demo") {
+		t.Fatalf("aarch64 index should not carry the x86_64 package: %s", got)
+	}
+
+	// An .apk request arrives in apk's reconstructed shape
+	// "<arch>/<name>-<version>.apk" (APKINDEX carries no filename), NOT as the
+	// github-relative FilePath. ServeRemote must resolve it back to the stored
+	// FilePath before redirecting to the backend releases_remote.
+	rec = httptest.NewRecorder()
+	req = httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-apk/x86_64/demo-1.2.3-r0.apk", nil)
+	if !p.ServeRemote(rec, req, remote, "x86_64/demo-1.2.3-r0.apk", proxyBase, store) {
+		t.Fatal("ServeRemote did not handle .apk")
+	}
+	if rec.Code != http.StatusFound {
+		t.Fatalf("want 302, got %d", rec.Code)
+	}
+	wantLoc := proxyBase + "/api/v1/remote/github/" + demoPath
+	if got := rec.Header().Get("Location"); got != wantLoc {
+		t.Fatalf("Location = %q, want %q (must be the stored FilePath, not the inbound path)", got, wantLoc)
+	}
+}
+
+// An apk download whose reconstructed "<arch>/<name>-<version>.apk" matches no
+// cached row must 404, never redirect to a bad path.
+func TestGitHubServeRemoteApkRedirectNotFound(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+
+	// Warm the cache so the store is populated but lacks the requested package.
+	if err := p.scan(context.Background(), remote, store); err != nil {
+		t.Fatalf("warm scan: %v", err)
+	}
+
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-apk/x86_64/nope-9.9.9.apk", nil)
+	if !p.ServeRemote(rec, req, remote, "x86_64/nope-9.9.9.apk", "https://x", store) {
+		t.Fatal("ServeRemote did not handle .apk")
+	}
+	if rec.Code != http.StatusNotFound {
+		t.Fatalf("want 404 for unknown package, got %d (Location=%q)", rec.Code, rec.Header().Get("Location"))
+	}
+}
+
+// apk requests the index at "./<arch>/APKINDEX.tar.gz"; ServeRemote must collapse
+// the dot-segment and synthesize the same index as the un-prefixed request.
+func TestGitHubServeRemoteApkDotSegment(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+	const proxyBase = "https://artifactapi.example"
+
+	serve := func(path string) *httptest.ResponseRecorder {
+		rec := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-apk/"+path, nil)
+		if !p.ServeRemote(rec, req, remote, path, proxyBase, store) {
+			t.Fatalf("ServeRemote did not handle %q", path)
+		}
+		return rec
+	}
+
+	plain, dotted := serve("x86_64/APKINDEX.tar.gz"), serve("./x86_64/APKINDEX.tar.gz")
+	if plain.Code != 200 || dotted.Code != 200 {
+		t.Fatalf("index: plain=%d dotted=%d, want 200/200", plain.Code, dotted.Code)
+	}
+	if !bytes.Equal(plain.Body.Bytes(), dotted.Body.Bytes()) {
+		t.Error("./<arch>/APKINDEX.tar.gz body differs from the un-prefixed body")
+	}
+}
+
+func TestGitHubServeRemoteRejectsNonPerArchIndex(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/x", nil)
+	if !p.ServeRemote(rec, req, fx.remote(), "APKINDEX.tar.gz", "https://x", store) {
+		t.Fatal("expected handled")
+	}
+	if rec.Code != http.StatusNotFound {
+		t.Fatalf("bare APKINDEX must 404 (per-arch required), got %d", rec.Code)
+	}
+}
+
+// A canceled inbound request must still serve the warm cache (detached context),
+// not turn the metadata read into a 500.
+func TestGitHubServeRemoteCanceledRequestServesCache(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+
+	if err := p.scan(context.Background(), remote, store); err != nil {
+		t.Fatalf("warm scan: %v", err)
+	}
+	p.mu.Lock()
+	p.lastScan[remote.Name] = time.Now()
+	p.mu.Unlock()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-apk/x86_64/APKINDEX.tar.gz", nil).WithContext(ctx)
+
+	if !p.ServeRemote(rec, req, remote, "x86_64/APKINDEX.tar.gz", "https://x", store) {
+		t.Fatal("ServeRemote did not handle APKINDEX")
+	}
+	if rec.Code != http.StatusOK {
+		t.Fatalf("canceled request must serve cache, not error; got code=%d body=%s", rec.Code, rec.Body.String())
+	}
+	if got := readAPKIndex(t, rec.Body.Bytes()); !strings.Contains(got, "P:demo") {
+		t.Fatalf("expected index served from cache, got %s", got)
+	}
+}
+
+func TestGitHubServeRemoteRedirectRequiresReleasesRemote(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+	remote.ReleasesRemote = ""
+
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/x", nil)
+	if !p.ServeRemote(rec, req, remote, demoPath, "https://x", store) {
+		t.Fatal("expected handled")
+	}
+	if rec.Code != http.StatusInternalServerError {
+		t.Fatalf("want 500 when releases_remote unset, got %d", rec.Code)
+	}
+}
+
+func TestGitHubScanPrunesRemovedAssets(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+
+	if err := p.scan(context.Background(), fx.remote(), store); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+	if rows, _ := store.ListAlpineMetadataEntries(context.Background(), "acme-apk"); len(rows) != 1 {
+		t.Fatalf("want 1 row after first scan, got %d", len(rows))
+	}
+
+	delete(fx.apkBytes, "demo-1.2.3-r0.apk")
+	if err := p.scan(context.Background(), fx.remote(), store); err != nil {
+		t.Fatalf("rescan: %v", err)
+	}
+	if rows, _ := store.ListAlpineMetadataEntries(context.Background(), "acme-apk"); len(rows) != 0 {
+		t.Fatalf("want 0 rows after prune, got %d", len(rows))
+	}
+}
+
+func TestGitHubAssetPatternFilter(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.apkBytes["other-9-r0.apk"] = testsupport.MinimalApk("other", "9-r0", "aarch64")
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+	remote.Patterns = []string{`^demo-.*\.apk$`}
+
+	if err := p.scan(context.Background(), remote, store); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+	rows, _ := store.ListAlpineMetadataEntries(context.Background(), "acme-apk")
+	if len(rows) != 1 || rows[0].Name != "demo" {
+		t.Fatalf("pattern filter failed, rows=%+v", rows)
+	}
+}
+
+// Multi-arch: each asset's index record lands under its own arch bucket.
+func TestGitHubServeRemotePerArchGrouping(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.apkBytes["demo-1.2.3-r0-aarch64.apk"] = testsupport.MinimalApk("demo", "1.2.3-r0", "aarch64")
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+	const proxyBase = "https://x"
+
+	if err := p.scan(context.Background(), remote, store); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+
+	serve := func(arch string) string {
+		rec := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, "/x", nil)
+		if !p.ServeRemote(rec, req, remote, arch+"/APKINDEX.tar.gz", proxyBase, store) {
+			t.Fatalf("ServeRemote did not handle %s", arch)
+		}
+		return readAPKIndex(t, rec.Body.Bytes())
+	}
+
+	x86 := serve("x86_64")
+	if !strings.Contains(x86, "A:x86_64") || strings.Contains(x86, "A:aarch64") {
+		t.Fatalf("x86_64 index leaked another arch: %s", x86)
+	}
+	arm := serve("aarch64")
+	if !strings.Contains(arm, "A:aarch64") || strings.Contains(arm, "A:x86_64") {
+		t.Fatalf("aarch64 index leaked another arch: %s", arm)
+	}
+}
+
+func readAPKIndex(t *testing.T, gzBytes []byte) string {
+	t.Helper()
+	gz, err := gzip.NewReader(bytes.NewReader(gzBytes))
+	if err != nil {
+		t.Fatalf("gzip: %v", err)
+	}
+	tr := tar.NewReader(gz)
+	for {
+		hdr, err := tr.Next()
+		if err != nil {
+			t.Fatal("APKINDEX member missing from tar.gz")
+		}
+		if strings.TrimPrefix(hdr.Name, "./") == "APKINDEX" {
+			body, err := io.ReadAll(tr)
+			if err != nil {
+				t.Fatalf("read APKINDEX: %v", err)
+			}
+			return string(body)
+		}
+	}
+}

internal/provider/alpine/syncer.go

@@ -0,0 +1,238 @@
+package alpine
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"log/slog"
+	"os"
+	"sync"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+const (
+	syncLeaseDuration    = 15 * time.Minute
+	defaultSyncFreshness = 5 * time.Minute
+	jobQueueDepth        = 256
+)
+
+// SyncStore is the persistence surface the alpine syncer needs: the metadata
+// cache it primes plus the shared sync-state coordination (remote enumeration
+// and the per-remote lease). *database.DB satisfies it.
+type SyncStore interface {
+	provider.RemoteMetadataStore
+	ListGitHubAlpineRemotes(ctx context.Context) ([]models.Remote, error)
+	ClaimGitHubAlpineSyncLease(ctx context.Context, remoteName, owner string, freshness, lease time.Duration) (claimed bool, etag string, err error)
+	ReleaseGitHubAlpineSyncLease(ctx context.Context, remoteName, owner, etag string, syncedAt time.Time) error
+}
+
+// SyncConfig tunes the shared syncer. Zero values fall back to safe defaults.
+type SyncConfig struct {
+	RatePerSec   float64
+	Burst        int
+	Workers      int
+	PollInterval time.Duration
+}
+
+type syncJob struct {
+	remote models.Remote
+	prime  bool
+}
+
+// Syncer is the single per-process background worker that keeps every
+// github_alpine remote's derived metadata fresh. It owns a deduped work queue, a
+// pool of workers, and a global token-bucket rate limiter shared across all
+// remotes and bound onto the github_alpine provider. Periodic checks are gated by
+// a shared DB lease so, across replicas, only one performs each scan.
+type Syncer struct {
+	store   SyncStore
+	prov    *GitHubProvider
+	limiter *rate.Limiter
+	cfg     SyncConfig
+	owner   string
+
+	jobs   chan syncJob
+	mu     sync.Mutex
+	active map[string]bool
+}
+
+// NewSyncer builds the syncer bound to the process-wide github_alpine provider
+// singleton. Call Run to start it.
+func NewSyncer(store SyncStore, cfg SyncConfig) *Syncer {
+	return newSyncer(store, gitHubProvider, cfg)
+}
+
+func newSyncer(store SyncStore, prov *GitHubProvider, cfg SyncConfig) *Syncer {
+	if cfg.RatePerSec <= 0 {
+		cfg.RatePerSec = 1
+	}
+	if cfg.Burst <= 0 {
+		cfg.Burst = 5
+	}
+	if cfg.Workers <= 0 {
+		cfg.Workers = 3
+	}
+	if cfg.PollInterval <= 0 {
+		cfg.PollInterval = 60 * time.Second
+	}
+
+	lim := rate.NewLimiter(rate.Limit(cfg.RatePerSec), cfg.Burst)
+	s := &Syncer{
+		store:   store,
+		prov:    prov,
+		limiter: lim,
+		cfg:     cfg,
+		owner:   leaseOwner(),
+		jobs:    make(chan syncJob, jobQueueDepth),
+		active:  map[string]bool{},
+	}
+	prov.limiter = lim
+	prov.syncer = s
+	return s
+}
+
+// Run starts the worker pool and the periodic scheduler and blocks until ctx is
+// canceled, at which point it drains in-flight scans and returns.
+func (s *Syncer) Run(ctx context.Context) {
+	slog.Info("github_alpine syncer started",
+		"rate_per_sec", s.cfg.RatePerSec, "burst", s.cfg.Burst,
+		"workers", s.cfg.Workers, "poll_interval", s.cfg.PollInterval, "owner", s.owner)
+
+	var wg sync.WaitGroup
+	for i := 0; i < s.cfg.Workers; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			s.worker(ctx)
+		}()
+	}
+
+	ticker := time.NewTicker(s.cfg.PollInterval)
+	defer ticker.Stop()
+
+	s.schedule(ctx)
+	for {
+		select {
+		case <-ctx.Done():
+			wg.Wait()
+			slog.Info("github_alpine syncer stopped")
+			return
+		case <-ticker.C:
+			s.schedule(ctx)
+		}
+	}
+}
+
+// schedule enqueues a periodic check for every github_alpine remote. The DB lease
+// enforces the per-remote mutable_ttl cadence and cross-replica coordination.
+func (s *Syncer) schedule(ctx context.Context) {
+	remotes, err := s.store.ListGitHubAlpineRemotes(ctx)
+	if err != nil {
+		slog.Error("github_alpine syncer: list remotes", "error", err)
+		return
+	}
+	for _, r := range remotes {
+		s.enqueue(r, false)
+	}
+}
+
+// EnqueuePrime queues an immediate background prime for a freshly created remote.
+func (s *Syncer) EnqueuePrime(remote models.Remote) {
+	if s == nil {
+		return
+	}
+	s.enqueue(remote, true)
+}
+
+// enqueue adds a job unless the remote is already queued or in-flight, coalescing
+// duplicate requests down to one scan. It never blocks.
+func (s *Syncer) enqueue(remote models.Remote, prime bool) {
+	s.mu.Lock()
+	if s.active[remote.Name] {
+		s.mu.Unlock()
+		return
+	}
+	s.active[remote.Name] = true
+	s.mu.Unlock()
+
+	select {
+	case s.jobs <- syncJob{remote: remote, prime: prime}:
+	default:
+		s.mu.Lock()
+		delete(s.active, remote.Name)
+		s.mu.Unlock()
+	}
+}
+
+func (s *Syncer) worker(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case job := <-s.jobs:
+			s.process(ctx, job)
+		}
+	}
+}
+
+// process claims the shared lease and, if won, runs an incremental scan. Losing
+// the claim (another replica scanning, or not yet due) is a no-op.
+func (s *Syncer) process(ctx context.Context, job syncJob) {
+	defer func() {
+		s.mu.Lock()
+		delete(s.active, job.remote.Name)
+		s.mu.Unlock()
+	}()
+
+	freshness := time.Duration(job.remote.MutableTTL) * time.Second
+	if freshness <= 0 {
+		freshness = defaultSyncFreshness
+	}
+	if job.prime {
+		freshness = 0
+	}
+
+	claimed, etag, err := s.store.ClaimGitHubAlpineSyncLease(ctx, job.remote.Name, s.owner, freshness, syncLeaseDuration)
+	if err != nil {
+		slog.Error("github_alpine syncer: claim lease", "remote", job.remote.Name, "error", err)
+		return
+	}
+	if !claimed {
+		return
+	}
+
+	scanCtx, cancel := context.WithTimeout(ctx, s.prov.scanTimeout)
+	defer cancel()
+
+	newEtag, changed, scanErr := s.prov.scanWithState(scanCtx, job.remote, s.store, etag)
+	releaseEtag := etag
+	if scanErr == nil {
+		releaseEtag = newEtag
+	} else {
+		slog.Error("github_alpine syncer: scan failed", "remote", job.remote.Name, "error", scanErr)
+	}
+
+	relCtx, relCancel := context.WithTimeout(context.WithoutCancel(ctx), 10*time.Second)
+	defer relCancel()
+	if err := s.store.ReleaseGitHubAlpineSyncLease(relCtx, job.remote.Name, s.owner, releaseEtag, time.Now()); err != nil {
+		slog.Warn("github_alpine syncer: release lease", "remote", job.remote.Name, "error", err)
+	}
+
+	if scanErr == nil && changed {
+		slog.Info("github_alpine syncer: refreshed", "remote", job.remote.Name, "prime", job.prime)
+	}
+}
+
+// leaseOwner is a per-replica identity for the lease: hostname plus a random
+// suffix so restarts and colocated replicas never collide.
+func leaseOwner() string {
+	host, _ := os.Hostname()
+	var b [6]byte
+	_, _ = rand.Read(b[:])
+	return host + "-" + hex.EncodeToString(b[:])
+}

internal/provider/alpine/syncer_test.go

@@ -0,0 +1,300 @@
+package alpine
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"testing"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// fakeSyncStore is an in-memory SyncStore: the metadata cache (via the embedded
+// fakeStore) plus the shared sync-state lease, whose claim mirrors the atomic
+// semantics of the real SQL (recency gate AND no live lease).
+type fakeSyncStore struct {
+	*fakeStore
+
+	mu         sync.Mutex
+	remotes    []models.Remote
+	leaseOwner map[string]string
+	leaseExp   map[string]time.Time
+	lastSynced map[string]time.Time
+	etags      map[string]string
+}
+
+func newFakeSyncStore() *fakeSyncStore {
+	return &fakeSyncStore{
+		fakeStore:  newFakeStore(),
+		leaseOwner: map[string]string{},
+		leaseExp:   map[string]time.Time{},
+		lastSynced: map[string]time.Time{},
+		etags:      map[string]string{},
+	}
+}
+
+func (f *fakeSyncStore) ListGitHubAlpineRemotes(_ context.Context) ([]models.Remote, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return append([]models.Remote(nil), f.remotes...), nil
+}
+
+func (f *fakeSyncStore) ClaimGitHubAlpineSyncLease(_ context.Context, name, owner string, freshness, lease time.Duration) (bool, string, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	now := time.Now()
+	ls, hasLS := f.lastSynced[name]
+	exp, hasExp := f.leaseExp[name]
+	freshOK := !hasLS || now.Sub(ls) >= freshness
+	leaseOK := !hasExp || exp.Before(now)
+	if freshOK && leaseOK {
+		f.leaseOwner[name] = owner
+		f.leaseExp[name] = now.Add(lease)
+		return true, f.etags[name], nil
+	}
+	return false, "", nil
+}
+
+func (f *fakeSyncStore) ReleaseGitHubAlpineSyncLease(_ context.Context, name, owner, etag string, syncedAt time.Time) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if f.leaseOwner[name] != owner {
+		return nil
+	}
+	f.lastSynced[name] = syncedAt
+	f.etags[name] = etag
+	delete(f.leaseOwner, name)
+	delete(f.leaseExp, name)
+	return nil
+}
+
+func testSyncConfig() SyncConfig {
+	return SyncConfig{RatePerSec: 1000, Burst: 100, Workers: 1, PollInterval: time.Hour}
+}
+
+// (a) A 304 conditional response must derive nothing: no asset fetches and
+// changed=false, so an unchanged repo is nearly free.
+func TestSyncerConditionalNotModifiedSkipsDerive(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.etag = `"v1"`
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+
+	etag1, changed, err := p.scanWithState(context.Background(), remote, store, "")
+	if err != nil {
+		t.Fatalf("first scan: %v", err)
+	}
+	if !changed || etag1 != `"v1"` {
+		t.Fatalf("first scan changed=%v etag=%q, want true and \"v1\"", changed, etag1)
+	}
+	priorRange := fx.rangeHit["demo-1.2.3-r0.apk"]
+	if priorRange == 0 {
+		t.Fatal("first scan should have fetched the asset .PKGINFO")
+	}
+
+	etag2, changed2, err := p.scanWithState(context.Background(), remote, store, etag1)
+	if err != nil {
+		t.Fatalf("second scan: %v", err)
+	}
+	if changed2 {
+		t.Fatal("304 scan must report changed=false")
+	}
+	if etag2 != etag1 {
+		t.Fatalf("etag changed across 304: %q -> %q", etag1, etag2)
+	}
+	if fx.notModHit != 1 {
+		t.Fatalf("want exactly one 304 releases response, got %d", fx.notModHit)
+	}
+	if got := fx.rangeHit["demo-1.2.3-r0.apk"]; got != priorRange {
+		t.Fatalf("304 scan re-fetched asset .PKGINFO: %d -> %d", priorRange, got)
+	}
+}
+
+// (b) On a real change, only the newly added asset is derived.
+func TestSyncerIncrementalDerivesOnlyNewAsset(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.etag = `"v1"`
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+
+	if _, _, err := p.scanWithState(context.Background(), remote, store, ""); err != nil {
+		t.Fatalf("first scan: %v", err)
+	}
+	demoRange := fx.rangeHit["demo-1.2.3-r0.apk"]
+
+	fx.apkBytes["other-9-r0.apk"] = testsupport.MinimalApk("other", "9-r0", "aarch64")
+	fx.etag = `"v2"`
+
+	if _, changed, err := p.scanWithState(context.Background(), remote, store, `"v1"`); err != nil || !changed {
+		t.Fatalf("second scan changed=%v err=%v", changed, err)
+	}
+
+	rows, _ := store.ListAlpineMetadataEntries(context.Background(), remote.Name)
+	if len(rows) != 2 {
+		t.Fatalf("want 2 cached rows after incremental derive, got %d", len(rows))
+	}
+	if got := fx.rangeHit["demo-1.2.3-r0.apk"]; got != demoRange {
+		t.Fatalf("already-cached asset was re-fetched: %d -> %d", demoRange, got)
+	}
+	if fx.rangeHit["other-9-r0.apk"] == 0 {
+		t.Fatal("newly added asset was not derived")
+	}
+}
+
+// (c) The shared limiter caps the request rate.
+func TestRateLimiterCapsRequestRate(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	p.limiter = rate.NewLimiter(rate.Every(120*time.Millisecond), 1)
+	remote := fx.remote()
+
+	start := time.Now()
+	for i := 0; i < 3; i++ {
+		if _, _, _, err := p.fetchReleases(context.Background(), remote, ""); err != nil {
+			t.Fatalf("fetchReleases %d: %v", i, err)
+		}
+	}
+	if elapsed := time.Since(start); elapsed < 200*time.Millisecond {
+		t.Fatalf("rate limiter did not throttle: 3 calls took %v, want >= 200ms", elapsed)
+	}
+}
+
+// (d) Concurrent enqueues for the same remote coalesce to a single queued job.
+func TestSyncerEnqueueDedup(t *testing.T) {
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	s := newSyncer(store, p, testSyncConfig())
+	remote := models.Remote{Name: "acme-apk", PackageType: models.PackageGitHubAlpine, MutableTTL: 3600}
+
+	var wg sync.WaitGroup
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+		go func() { defer wg.Done(); s.enqueue(remote, false) }()
+	}
+	wg.Wait()
+
+	if got := len(s.jobs); got != 1 {
+		t.Fatalf("want exactly 1 coalesced job, got %d", got)
+	}
+}
+
+// (e) Prime-on-create enqueues a prime job.
+func TestSyncerEnqueuePrime(t *testing.T) {
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	s := newSyncer(store, p, testSyncConfig())
+	remote := models.Remote{Name: "acme-apk", PackageType: models.PackageGitHubAlpine, MutableTTL: 3600}
+
+	s.EnqueuePrime(remote)
+	select {
+	case job := <-s.jobs:
+		if !job.prime || job.remote.Name != "acme-apk" {
+			t.Fatalf("bad prime job: %+v", job)
+		}
+	default:
+		t.Fatal("EnqueuePrime did not enqueue a job")
+	}
+}
+
+// (f) A held lease prevents a second replica from scanning.
+func TestSyncerLeasePreventsSecondReplica(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.etag = `"v1"`
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	s := newSyncer(store, p, testSyncConfig())
+	remote := fx.remote()
+
+	claimed, _, err := store.ClaimGitHubAlpineSyncLease(context.Background(), remote.Name, "replica-1", time.Duration(remote.MutableTTL)*time.Second, syncLeaseDuration)
+	if err != nil || !claimed {
+		t.Fatalf("replica-1 claim: claimed=%v err=%v", claimed, err)
+	}
+
+	s.process(context.Background(), syncJob{remote: remote})
+
+	if fx.releasesHit != 0 {
+		t.Fatalf("second replica scanned while lease held: %d releases calls", fx.releasesHit)
+	}
+	if rows, _ := store.ListAlpineMetadataEntries(context.Background(), remote.Name); len(rows) != 0 {
+		t.Fatalf("second replica derived metadata while lease held: %d rows", len(rows))
+	}
+}
+
+// With the syncer wired and the cache empty, an index request enqueues a prime
+// and returns a retryable 503 when it has not landed within the cold wait.
+func TestServeRemoteColdStartReturns503(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	p.coldWait = 300 * time.Millisecond
+	_ = newSyncer(store, p, testSyncConfig()) // binds p.syncer, but no workers running
+	remote := fx.remote()
+
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-apk/x86_64/APKINDEX.tar.gz", nil)
+	if !p.ServeRemote(rec, req, remote, "x86_64/APKINDEX.tar.gz", "https://x", store) {
+		t.Fatal("ServeRemote did not handle APKINDEX")
+	}
+	if rec.Code != http.StatusServiceUnavailable {
+		t.Fatalf("cold empty cache must return 503, got %d", rec.Code)
+	}
+	if rec.Header().Get("Retry-After") == "" {
+		t.Fatal("503 should carry Retry-After")
+	}
+	if got := len(p.syncer.jobs); got != 1 {
+		t.Fatalf("cold start did not enqueue a prime, jobs=%d", got)
+	}
+}
+
+// With the cache warm, the same request serves the index immediately (no 503).
+func TestServeRemoteWarmCacheServesImmediately(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	_ = newSyncer(store, p, testSyncConfig())
+	remote := fx.remote()
+
+	if err := p.scan(context.Background(), remote, store); err != nil {
+		t.Fatalf("warm scan: %v", err)
+	}
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-apk/x86_64/APKINDEX.tar.gz", nil)
+	if !p.ServeRemote(rec, req, remote, "x86_64/APKINDEX.tar.gz", "https://x", store) {
+		t.Fatal("ServeRemote did not handle APKINDEX")
+	}
+	if rec.Code != http.StatusOK {
+		t.Fatalf("warm cache must serve 200, got %d body=%s", rec.Code, rec.Body.String())
+	}
+}
+
+// A prime job (freshness 0) runs even right after a sync; a periodic job at the
+// same moment is gated by the recency window.
+func TestSyncerPrimeBypassesRecencyPeriodicDoesNot(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.etag = `"v1"`
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	s := newSyncer(store, p, testSyncConfig())
+	remote := fx.remote()
+
+	var _ provider.RemoteMetadataStore = store
+
+	s.process(context.Background(), syncJob{remote: remote, prime: true})
+	if rows, _ := store.ListAlpineMetadataEntries(context.Background(), remote.Name); len(rows) != 1 {
+		t.Fatalf("prime did not derive: %d rows", len(rows))
+	}
+	releasesAfterPrime := fx.releasesHit
+
+	s.process(context.Background(), syncJob{remote: remote, prime: false})
+	if fx.releasesHit != releasesAfterPrime {
+		t.Fatalf("periodic scan ran inside recency window: %d -> %d releases calls", releasesAfterPrime, fx.releasesHit)
+	}
+}

internal/provider/deb/deb.go

@@ -0,0 +1,462 @@
+package deb
+
+import (
+	"archive/tar"
+	"bufio"
+	"bytes"
+	"compress/gzip"
+	"context"
+	"crypto/md5"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"path"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/klauspost/compress/zstd"
+	"github.com/ulikunitz/xz"
+
+	"git.unkin.net/unkin/artifactapi/internal/auth"
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/storage"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+func init() {
+	provider.Register(&Provider{})
+}
+
+// mutableRe marks the apt index surface (both the flat local repo and a proxied
+// Debian/Ubuntu mirror's dists/ tree) so the caching engine revalidates it
+// instead of freezing it like an immutable .deb.
+var mutableRe = []*regexp.Regexp{
+	regexp.MustCompile(`(^|/)Packages(\.gz|\.xz|\.bz2)?$`),
+	regexp.MustCompile(`(^|/)Sources(\.gz|\.xz|\.bz2)?$`),
+	regexp.MustCompile(`(^|/)Release$`),
+	regexp.MustCompile(`(^|/)InRelease$`),
+	regexp.MustCompile(`(^|/)Release\.gpg$`),
+	regexp.MustCompile(`(^|/)Contents-`),
+	regexp.MustCompile(`^dists/`),
+	regexp.MustCompile(`/by-hash/`),
+}
+
+type Provider struct{}
+
+func (p *Provider) Type() models.PackageType { return models.PackageDeb }
+
+func (p *Provider) Classify(path string) provider.Mutability {
+	for _, re := range mutableRe {
+		if re.MatchString(path) {
+			return provider.Mutable
+		}
+	}
+	return provider.Immutable
+}
+
+func (p *Provider) ContentType(path string) string {
+	switch {
+	case strings.HasSuffix(path, ".deb"):
+		return "application/vnd.debian.binary-package"
+	case strings.HasSuffix(path, ".gz"):
+		return "application/gzip"
+	case strings.HasSuffix(path, ".xz"):
+		return "application/x-xz"
+	case strings.HasSuffix(path, "Packages"), strings.HasSuffix(path, "Release"),
+		strings.HasSuffix(path, "InRelease"), strings.HasSuffix(path, "Sources"):
+		return "text/plain"
+	}
+	return "application/octet-stream"
+}
+
+func (p *Provider) UpstreamURL(remote models.Remote, path string) string {
+	return strings.TrimRight(remote.BaseURL, "/") + "/" + strings.TrimLeft(path, "/")
+}
+
+func (p *Provider) RewriteResponse(_ []byte, _ models.Remote, _ string) ([]byte, error) {
+	return nil, nil
+}
+
+func (p *Provider) AuthHeaders(_ context.Context, remote models.Remote) (http.Header, error) {
+	return auth.BasicHeaders(remote), nil
+}
+
+func (p *Provider) ValidateUpload(filePath string) (storagePath, contentType string, err error) {
+	filename := filePath
+	if idx := strings.LastIndex(filePath, "/"); idx >= 0 {
+		filename = filePath[idx+1:]
+	}
+
+	if !strings.HasSuffix(strings.ToLower(filename), ".deb") {
+		return "", "", fmt.Errorf("file must be a .deb package")
+	}
+
+	return "pool/" + filename, "application/vnd.debian.binary-package", nil
+}
+
+func (p *Provider) UploadResponse(storagePath, contentHash string, sizeBytes int64) map[string]any {
+	filename := strings.TrimPrefix(storagePath, "pool/")
+	return map[string]any{
+		"filename":     filename,
+		"content_hash": contentHash,
+		"size_bytes":   sizeBytes,
+	}
+}
+
+func (p *Provider) AfterUpload(ctx context.Context, repoName, storagePath, contentHash string, blobs provider.BlobReader, db provider.MetadataStore) {
+	s3Key := storage.BlobKey(strings.TrimPrefix(contentHash, "sha256:"))
+
+	reader, blobSize, err := blobs.Download(ctx, s3Key)
+	if err != nil {
+		slog.Error("deb metadata: download failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	defer reader.Close()
+
+	raw, err := io.ReadAll(reader)
+	if err != nil {
+		slog.Error("deb metadata: read failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+
+	control, err := extractControl(raw)
+	if err != nil {
+		slog.Error("deb metadata: parse failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	fields := parseControlFields(control)
+
+	sum := md5.Sum(raw)
+	meta := &provider.DebMetadata{
+		RepoName:     repoName,
+		FilePath:     storagePath,
+		ContentHash:  contentHash,
+		Name:         fields["Package"],
+		Version:      fields["Version"],
+		Architecture: fields["Architecture"],
+		Control:      strings.TrimRight(control, "\n"),
+		Size:         blobSize,
+		MD5:          hex.EncodeToString(sum[:]),
+		SHA256:       strings.TrimPrefix(contentHash, "sha256:"),
+	}
+
+	if meta.Name == "" {
+		slog.Error("deb metadata: control missing Package field", "repo", repoName, "path", storagePath)
+		return
+	}
+
+	if err := db.InsertDebMetadata(ctx, meta); err != nil {
+		slog.Error("deb metadata: insert failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+
+	slog.Info("deb metadata: parsed", "repo", repoName, "name", meta.Name, "version", meta.Version, "arch", meta.Architecture)
+}
+
+func (p *Provider) AfterDelete(ctx context.Context, repoName, storagePath string, db provider.MetadataDeleter) error {
+	if err := db.DeleteDebMetadata(ctx, repoName, storagePath); err != nil {
+		slog.Error("deb metadata: delete failed", "repo", repoName, "path", storagePath, "error", err)
+		return err
+	}
+	slog.Info("deb metadata: deleted", "repo", repoName, "path", storagePath)
+	return nil
+}
+
+// extractControl reads a .deb (an ar archive), locates the control.tar.* member,
+// decompresses it, and returns the raw ./control paragraph. Pure Go: no dpkg.
+func extractControl(deb []byte) (string, error) {
+	members, err := readAr(deb)
+	if err != nil {
+		return "", err
+	}
+
+	var name string
+	var data []byte
+	for _, m := range members {
+		if strings.HasPrefix(m.name, "control.tar") {
+			name = m.name
+			data = m.data
+			break
+		}
+	}
+	if data == nil {
+		return "", errors.New("no control.tar member in .deb")
+	}
+
+	tarBytes, err := decompress(name, data)
+	if err != nil {
+		return "", err
+	}
+
+	return readControlParagraph(tarBytes)
+}
+
+// readControlParagraph scans a decompressed control.tar and returns the raw
+// ./control paragraph. Shared by the local upload path (extractControl) and the
+// github_deb ranged-prefix parser.
+func readControlParagraph(controlTar []byte) (string, error) {
+	tr := tar.NewReader(bytes.NewReader(controlTar))
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return "", fmt.Errorf("read control.tar: %w", err)
+		}
+		clean := strings.TrimPrefix(hdr.Name, "./")
+		if clean == "control" {
+			b, err := io.ReadAll(tr)
+			if err != nil {
+				return "", fmt.Errorf("read control file: %w", err)
+			}
+			return string(b), nil
+		}
+	}
+	return "", errors.New("no ./control in control.tar")
+}
+
+func decompress(name string, data []byte) ([]byte, error) {
+	switch {
+	case strings.HasSuffix(name, ".gz"):
+		zr, err := gzip.NewReader(bytes.NewReader(data))
+		if err != nil {
+			return nil, err
+		}
+		defer zr.Close()
+		return io.ReadAll(zr)
+	case strings.HasSuffix(name, ".xz"):
+		xr, err := xz.NewReader(bytes.NewReader(data))
+		if err != nil {
+			return nil, err
+		}
+		return io.ReadAll(xr)
+	case strings.HasSuffix(name, ".zst"):
+		zr, err := zstd.NewReader(bytes.NewReader(data))
+		if err != nil {
+			return nil, err
+		}
+		defer zr.Close()
+		return io.ReadAll(zr)
+	case strings.HasSuffix(name, ".tar"):
+		return data, nil
+	}
+	return nil, fmt.Errorf("unsupported control.tar compression: %s", name)
+}
+
+type arMember struct {
+	name string
+	data []byte
+}
+
+// readAr parses the (trivial) Unix ar archive that wraps a .deb. Each member has
+// a 60-byte header; the size field is decimal ASCII and data is padded to an
+// even offset.
+func readAr(data []byte) ([]arMember, error) {
+	const magic = "!<arch>\n"
+	if len(data) < len(magic) || string(data[:len(magic)]) != magic {
+		return nil, errors.New("not an ar archive")
+	}
+	off := len(magic)
+
+	var members []arMember
+	for off+60 <= len(data) {
+		hdr := data[off : off+60]
+		off += 60
+
+		name := strings.TrimRight(string(hdr[0:16]), " ")
+		name = strings.TrimSuffix(name, "/")
+		size, err := strconv.ParseInt(strings.TrimSpace(string(hdr[48:58])), 10, 64)
+		if err != nil {
+			return nil, fmt.Errorf("bad ar size for %q: %w", name, err)
+		}
+		if off+int(size) > len(data) {
+			return nil, fmt.Errorf("truncated ar member %q", name)
+		}
+		members = append(members, arMember{name: name, data: data[off : off+int(size)]})
+		off += int(size)
+		if size%2 == 1 {
+			off++
+		}
+	}
+	return members, nil
+}
+
+// parseControlFields reads the single-line fields of an RFC822-style control
+// paragraph. Continuation lines (leading whitespace) belong to the previous
+// field and are ignored here since only Package/Version/Architecture are read.
+func parseControlFields(control string) map[string]string {
+	fields := map[string]string{}
+	sc := bufio.NewScanner(strings.NewReader(control))
+	sc.Buffer(make([]byte, 0, 64*1024), 1024*1024)
+	for sc.Scan() {
+		line := sc.Text()
+		if line == "" || line[0] == ' ' || line[0] == '\t' {
+			continue
+		}
+		idx := strings.IndexByte(line, ':')
+		if idx < 0 {
+			continue
+		}
+		key := strings.TrimSpace(line[:idx])
+		if _, seen := fields[key]; seen {
+			continue
+		}
+		fields[key] = strings.TrimSpace(line[idx+1:])
+	}
+	return fields
+}
+
+// normalizeIndexPath collapses apt's verbatim dist prefix from a flat-repo
+// request. For `deb ... <repo>/ ./`, apt appends the "./" dist literally and asks
+// for "./Packages" (and "./Release", "./InRelease"); dot-segments must be
+// collapsed so the index matcher sees "Packages". A no-op for pool/*.deb paths.
+func normalizeIndexPath(p string) string {
+	return strings.TrimPrefix(path.Clean("/"+p), "/")
+}
+
+func (p *Provider) ServeLocalIndex(w http.ResponseWriter, r *http.Request, files provider.FileStore, repoName, reqPath string) bool {
+	path := normalizeIndexPath(reqPath)
+	switch path {
+	case "Packages", "Packages.gz", "Release":
+	default:
+		return false
+	}
+
+	reader, ok := files.(provider.DebMetadataReader)
+	if !ok {
+		http.Error(w, "deb metadata not available", http.StatusInternalServerError)
+		return true
+	}
+
+	metas, err := reader.ListDebMetadataEntries(r.Context(), repoName)
+	if err != nil {
+		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+			slog.Warn("deb: metadata read canceled", "repo", repoName, "error", err)
+			http.Error(w, "metadata read canceled", http.StatusServiceUnavailable)
+			return true
+		}
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return true
+	}
+
+	switch path {
+	case "Packages":
+		w.Header().Set("Content-Type", "text/plain")
+		w.WriteHeader(http.StatusOK)
+		w.Write(generatePackages(metas))
+	case "Packages.gz":
+		w.Header().Set("Content-Type", "application/gzip")
+		w.WriteHeader(http.StatusOK)
+		w.Write(gzipBytes(generatePackages(metas)))
+	case "Release":
+		w.Header().Set("Content-Type", "text/plain")
+		w.WriteHeader(http.StatusOK)
+		w.Write(generateRelease(metas))
+	}
+	return true
+}
+
+func (p *Provider) GenerateLocalIndex(ctx context.Context, files provider.FileStore, repoName, path string) ([]byte, error) {
+	return nil, fmt.Errorf("deb local index generation for virtual repos not supported")
+}
+
+// generatePackages emits the flat-repo Packages file: each package's raw control
+// stanza followed by the apt-required Filename/Size/MD5sum/SHA256 fields, blank
+// line separated.
+func generatePackages(metas []provider.DebMetadata) []byte {
+	var b bytes.Buffer
+	for _, m := range metas {
+		b.WriteString(strings.TrimRight(m.Control, "\n"))
+		b.WriteString("\n")
+		fmt.Fprintf(&b, "Filename: %s\n", m.FilePath)
+		fmt.Fprintf(&b, "Size: %d\n", m.Size)
+		if m.MD5 != "" {
+			fmt.Fprintf(&b, "MD5sum: %s\n", m.MD5)
+		}
+		if m.SHA256 != "" {
+			fmt.Fprintf(&b, "SHA256: %s\n", m.SHA256)
+		}
+		b.WriteString("\n")
+	}
+	return b.Bytes()
+}
+
+func generateRelease(metas []provider.DebMetadata) []byte {
+	packages := generatePackages(metas)
+	packagesGz := gzipBytes(packages)
+
+	arches := uniqueArches(metas)
+
+	var b bytes.Buffer
+	fmt.Fprintf(&b, "Date: %s\n", releaseDate(metas).Format(time.RFC1123Z))
+	fmt.Fprintf(&b, "Architectures: %s\n", strings.Join(arches, " "))
+	b.WriteString("Acquire-By-Hash: no\n")
+
+	b.WriteString("MD5Sum:\n")
+	writeReleaseEntry(&b, md5Hex(packages), len(packages), "Packages")
+	writeReleaseEntry(&b, md5Hex(packagesGz), len(packagesGz), "Packages.gz")
+
+	b.WriteString("SHA256:\n")
+	writeReleaseEntry(&b, sha256Hex(packages), len(packages), "Packages")
+	writeReleaseEntry(&b, sha256Hex(packagesGz), len(packagesGz), "Packages.gz")
+
+	return b.Bytes()
+}
+
+// releaseDate derives the Release Date: from the newest package's persisted
+// created_at (in UTC) so the file is byte-identical across the no-affinity
+// replicas and across regenerations (issue #117); an empty repo falls back to
+// the Unix epoch. This never uses wall clock, which also keeps Date: from
+// running ahead of any Valid-Until logic.
+func releaseDate(metas []provider.DebMetadata) time.Time {
+	newest := time.Unix(0, 0)
+	for _, m := range metas {
+		if m.CreatedAt.After(newest) {
+			newest = m.CreatedAt
+		}
+	}
+	return newest.UTC()
+}
+
+func writeReleaseEntry(b *bytes.Buffer, hash string, size int, name string) {
+	fmt.Fprintf(b, " %s %d %s\n", hash, size, name)
+}
+
+func uniqueArches(metas []provider.DebMetadata) []string {
+	seen := map[string]bool{}
+	var out []string
+	for _, m := range metas {
+		a := m.Architecture
+		if a == "" || seen[a] {
+			continue
+		}
+		seen[a] = true
+		out = append(out, a)
+	}
+	return out
+}
+
+func gzipBytes(data []byte) []byte {
+	var buf bytes.Buffer
+	gz := gzip.NewWriter(&buf)
+	gz.Write(data)
+	gz.Close()
+	return buf.Bytes()
+}
+
+func md5Hex(data []byte) string {
+	h := md5.Sum(data)
+	return hex.EncodeToString(h[:])
+}
+
+func sha256Hex(data []byte) string {
+	h := sha256.Sum256(data)
+	return hex.EncodeToString(h[:])
+}

internal/provider/deb/deb_deterministic_test.go

@@ -0,0 +1,172 @@
+package deb
+
+import (
+	"bytes"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+)
+
+// debFixture returns a fixed set of rows with persisted created_at values, in
+// the total order ListDebMetadataEntries produces (name, version, arch,
+// file_path), so the generators are exercised on a stable input.
+func debFixture() []provider.DebMetadata {
+	t1 := time.Date(2026, 3, 1, 8, 30, 0, 0, time.UTC)
+	t2 := time.Date(2026, 4, 15, 12, 0, 0, 0, time.UTC) // newest
+	return []provider.DebMetadata{
+		{
+			RepoName: "r", FilePath: "pool/aaa_1.0_amd64.deb", ContentHash: "sha256:aa",
+			Name: "aaa", Version: "1.0", Architecture: "amd64",
+			Control: "Package: aaa\nVersion: 1.0\nArchitecture: amd64",
+			Size:    100, MD5: "d41d8cd98f00b204e9800998ecf8427e", SHA256: "aa", CreatedAt: t1,
+		},
+		{
+			RepoName: "r", FilePath: "pool/bbb_2.0_arm64.deb", ContentHash: "sha256:bb",
+			Name: "bbb", Version: "2.0", Architecture: "arm64",
+			Control: "Package: bbb\nVersion: 2.0\nArchitecture: arm64",
+			Size:    200, MD5: "0cc175b9c0f1b6a831c399e269772661", SHA256: "bb", CreatedAt: t2,
+		},
+	}
+}
+
+// TestDebGeneratorsDeterministic asserts the served bytes are a pure function of
+// DB state: Packages, Packages.gz and Release are byte-identical across two
+// generations separated by wall-clock time. Fails against the old
+// time.Now()-stamped Release Date:.
+func TestDebGeneratorsDeterministic(t *testing.T) {
+	metas := debFixture()
+
+	pkgs1 := generatePackages(metas)
+	rel1 := generateRelease(metas)
+	gz1 := gzipBytes(pkgs1)
+
+	time.Sleep(10 * time.Millisecond)
+
+	pkgs2 := generatePackages(metas)
+	rel2 := generateRelease(metas)
+	gz2 := gzipBytes(pkgs2)
+
+	if !bytes.Equal(pkgs1, pkgs2) {
+		t.Error("Packages differs across generations")
+	}
+	if !bytes.Equal(gz1, gz2) {
+		t.Error("Packages.gz differs across generations")
+	}
+	if !bytes.Equal(rel1, rel2) {
+		t.Errorf("Release differs across generations:\n--- first ---\n%s\n--- second ---\n%s", rel1, rel2)
+	}
+}
+
+// TestDebReleaseDateUsesPersistedCreatedAt pins the Release Date: to the newest
+// persisted created_at (RFC1123Z, UTC), not wall clock. Fails against the old
+// time.Now() code.
+func TestDebReleaseDateUsesPersistedCreatedAt(t *testing.T) {
+	metas := debFixture()
+	want := time.Date(2026, 4, 15, 12, 0, 0, 0, time.UTC).Format(time.RFC1123Z)
+
+	rel := string(generateRelease(metas))
+	var got string
+	for _, line := range strings.Split(rel, "\n") {
+		if strings.HasPrefix(line, "Date:") {
+			got = strings.TrimSpace(strings.TrimPrefix(line, "Date:"))
+			break
+		}
+	}
+	if got != want {
+		t.Errorf("Release Date: = %q, want %q (newest created_at)", got, want)
+	}
+}
+
+// TestDebReleaseDateEmptyRepoIsEpoch guards the fallback: an empty repo yields a
+// deterministic epoch Date: rather than wall clock.
+func TestDebReleaseDateEmptyRepoIsEpoch(t *testing.T) {
+	want := time.Unix(0, 0).UTC().Format(time.RFC1123Z)
+	rel := string(generateRelease(nil))
+	if !strings.Contains(rel, "Date: "+want+"\n") {
+		t.Errorf("empty-repo Release missing epoch Date: %q\n%s", want, rel)
+	}
+}
+
+// TestDebReleaseChecksumsMatchServedBytes is the exact apt invariant: the
+// sha256/size (and md5/size) advertised for Packages and Packages.gz in Release
+// equal the sha256/size of the actual bytes ServeLocalIndex serves. apt rejects
+// any mismatch.
+func TestDebReleaseChecksumsMatchServedBytes(t *testing.T) {
+	metas := debFixture()
+
+	packages := generatePackages(metas)
+	packagesGz := gzipBytes(packages)
+	rel := string(generateRelease(metas))
+
+	wantSHA := map[string]struct {
+		hash string
+		size int
+	}{
+		"Packages":    {sha256Hex(packages), len(packages)},
+		"Packages.gz": {sha256Hex(packagesGz), len(packagesGz)},
+	}
+	wantMD5 := map[string]struct {
+		hash string
+		size int
+	}{
+		"Packages":    {md5Hex(packages), len(packages)},
+		"Packages.gz": {md5Hex(packagesGz), len(packagesGz)},
+	}
+
+	sha := parseReleaseSection(rel, "SHA256:")
+	md5s := parseReleaseSection(rel, "MD5Sum:")
+
+	for name, w := range wantSHA {
+		got, ok := sha[name]
+		if !ok {
+			t.Fatalf("Release SHA256 section missing %q", name)
+		}
+		if got.hash != w.hash || got.size != w.size {
+			t.Errorf("Release SHA256 %s = (%s, %d), served bytes are (%s, %d)", name, got.hash, got.size, w.hash, w.size)
+		}
+	}
+	for name, w := range wantMD5 {
+		got, ok := md5s[name]
+		if !ok {
+			t.Fatalf("Release MD5Sum section missing %q", name)
+		}
+		if got.hash != w.hash || got.size != w.size {
+			t.Errorf("Release MD5Sum %s = (%s, %d), served bytes are (%s, %d)", name, got.hash, got.size, w.hash, w.size)
+		}
+	}
+}
+
+type releaseEntry struct {
+	hash string
+	size int
+}
+
+// parseReleaseSection reads the indented " <hash> <size> <name>" lines that
+// follow a "SHA256:" / "MD5Sum:" header until the next non-indented line.
+func parseReleaseSection(release, header string) map[string]releaseEntry {
+	out := map[string]releaseEntry{}
+	lines := strings.Split(release, "\n")
+	in := false
+	for _, line := range lines {
+		if line == header {
+			in = true
+			continue
+		}
+		if !in {
+			continue
+		}
+		if !strings.HasPrefix(line, " ") {
+			break
+		}
+		fields := strings.Fields(line)
+		if len(fields) != 3 {
+			continue
+		}
+		size, _ := strconv.Atoi(fields[1])
+		out[fields[2]] = releaseEntry{hash: fields[0], size: size}
+	}
+	return out
+}

internal/provider/deb/deb_test.go

@@ -0,0 +1,408 @@
+package deb
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/klauspost/compress/zstd"
+	"github.com/ulikunitz/xz"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+type fakeBlobReader struct{ data []byte }
+
+func (f fakeBlobReader) Download(_ context.Context, _ string) (io.ReadCloser, int64, error) {
+	return io.NopCloser(bytes.NewReader(f.data)), int64(len(f.data)), nil
+}
+
+type errBlobReader struct{}
+
+func (errBlobReader) Download(_ context.Context, _ string) (io.ReadCloser, int64, error) {
+	return nil, 0, io.ErrUnexpectedEOF
+}
+
+// fakeDebStore satisfies provider.MetadataStore (both insert methods) and
+// records the deb row that AfterUpload writes.
+type fakeDebStore struct{ inserted *provider.DebMetadata }
+
+func (f *fakeDebStore) InsertRPMMetadata(context.Context, *provider.RPMMetadata) error { return nil }
+func (f *fakeDebStore) InsertDebMetadata(_ context.Context, m *provider.DebMetadata) error {
+	f.inserted = m
+	return nil
+}
+
+type fakeDebReader struct{ metas []provider.DebMetadata }
+
+func (f fakeDebReader) ListDebMetadataEntries(context.Context, string) ([]provider.DebMetadata, error) {
+	return f.metas, nil
+}
+func (f fakeDebReader) ListFilesByPrefix(context.Context, string, string) ([]provider.FileEntry, error) {
+	return nil, nil
+}
+func (f fakeDebReader) ListPackages(context.Context, string) ([]string, error) { return nil, nil }
+
+type errDebReader struct{}
+
+func (errDebReader) ListDebMetadataEntries(context.Context, string) ([]provider.DebMetadata, error) {
+	return nil, io.ErrUnexpectedEOF
+}
+func (errDebReader) ListFilesByPrefix(context.Context, string, string) ([]provider.FileEntry, error) {
+	return nil, nil
+}
+func (errDebReader) ListPackages(context.Context, string) ([]string, error) { return nil, nil }
+
+func TestDebPureFuncs(t *testing.T) {
+	p := &Provider{}
+	if p.Type() != models.PackageDeb {
+		t.Errorf("type = %q", p.Type())
+	}
+	if out, _ := p.RewriteResponse(nil, models.Remote{}, "http://p"); out != nil {
+		t.Error("deb never rewrites")
+	}
+	if got := p.UpstreamURL(models.Remote{BaseURL: "https://mirror/"}, "/dists/bookworm/Release"); got != "https://mirror/dists/bookworm/Release" {
+		t.Errorf("upstream url %q", got)
+	}
+	h, _ := p.AuthHeaders(context.Background(), models.Remote{Username: "u", Password: "p"})
+	if h.Get("Authorization") == "" {
+		t.Error("auth header")
+	}
+}
+
+func TestDebClassify(t *testing.T) {
+	p := &Provider{}
+	tests := []struct {
+		path string
+		want provider.Mutability
+	}{
+		{"pool/foo_1.0_amd64.deb", provider.Immutable},
+		{"Packages", provider.Mutable},
+		{"Packages.gz", provider.Mutable},
+		{"Release", provider.Mutable},
+		{"InRelease", provider.Mutable},
+		{"Release.gpg", provider.Mutable},
+		{"dists/bookworm/main/binary-amd64/Packages", provider.Mutable},
+		{"dists/bookworm/Release", provider.Mutable},
+		{"dists/bookworm/main/by-hash/SHA256/abc", provider.Mutable},
+		{"dists/bookworm/main/Contents-amd64.gz", provider.Mutable},
+	}
+	for _, tt := range tests {
+		if got := p.Classify(tt.path); got != tt.want {
+			t.Errorf("Classify(%q) = %v, want %v", tt.path, got, tt.want)
+		}
+	}
+}
+
+func TestDebContentType(t *testing.T) {
+	p := &Provider{}
+	for path, want := range map[string]string{
+		"pool/foo_1.0_amd64.deb":              "application/vnd.debian.binary-package",
+		"dists/bookworm/main/bin/Packages.gz": "application/gzip",
+		"dists/bookworm/main/bin/Packages.xz": "application/x-xz",
+		"Packages":                            "text/plain",
+		"Release":                             "text/plain",
+		"InRelease":                           "text/plain",
+		"pool/other":                          "application/octet-stream",
+	} {
+		if got := p.ContentType(path); got != want {
+			t.Errorf("ContentType(%q) = %q, want %q", path, got, want)
+		}
+	}
+}
+
+func TestDebValidateUpload(t *testing.T) {
+	p := &Provider{}
+	sp, ct, err := p.ValidateUpload("dir/foo_1.0_amd64.deb")
+	if err != nil || sp != "pool/foo_1.0_amd64.deb" || ct != "application/vnd.debian.binary-package" {
+		t.Errorf("sp=%q ct=%q err=%v", sp, ct, err)
+	}
+	if _, _, err := p.ValidateUpload("foo.rpm"); err == nil {
+		t.Error("expected error for non-deb")
+	}
+	resp := p.UploadResponse("pool/foo_1.0_amd64.deb", "sha256:abc", 42)
+	if resp["filename"] != "foo_1.0_amd64.deb" || resp["content_hash"] != "sha256:abc" || resp["size_bytes"] != int64(42) {
+		t.Errorf("upload response %v", resp)
+	}
+}
+
+func TestDebAfterUpload(t *testing.T) {
+	data := testsupport.MinimalDeb("e2e-testpkg", "1.2.3", "amd64")
+	store := &fakeDebStore{}
+	(&Provider{}).AfterUpload(context.Background(), "myrepo", "pool/e2e-testpkg_1.2.3_amd64.deb",
+		"sha256:deadbeef", fakeBlobReader{data: data}, store)
+
+	m := store.inserted
+	if m == nil {
+		t.Fatal("no metadata inserted")
+	}
+	if m.Name != "e2e-testpkg" || m.Version != "1.2.3" || m.Architecture != "amd64" {
+		t.Errorf("unexpected metadata: %+v", m)
+	}
+	if m.Size != int64(len(data)) {
+		t.Errorf("Size = %d, want %d", m.Size, len(data))
+	}
+	if m.SHA256 != "deadbeef" {
+		t.Errorf("SHA256 = %q, want deadbeef", m.SHA256)
+	}
+	if m.MD5 == "" {
+		t.Error("MD5 not computed")
+	}
+	if !strings.Contains(m.Control, "Package: e2e-testpkg") {
+		t.Errorf("raw control not stored: %q", m.Control)
+	}
+	// The raw stanza is stored verbatim (no trailing newline) so Packages can
+	// reproduce it faithfully.
+	if strings.HasSuffix(m.Control, "\n") {
+		t.Error("control should be trimmed of trailing newline")
+	}
+}
+
+func TestDebAfterUploadErrors(t *testing.T) {
+	// Download failure: no insert, no panic.
+	store := &fakeDebStore{}
+	(&Provider{}).AfterUpload(context.Background(), "r", "p", "sha256:x", errBlobReader{}, store)
+	if store.inserted != nil {
+		t.Error("no metadata should be inserted on download error")
+	}
+	// Not a .deb (ar) archive.
+	store2 := &fakeDebStore{}
+	(&Provider{}).AfterUpload(context.Background(), "r", "p", "sha256:x", fakeBlobReader{data: []byte("not a deb")}, store2)
+	if store2.inserted != nil {
+		t.Error("no metadata should be inserted on parse error")
+	}
+}
+
+func TestDebControlDecompression(t *testing.T) {
+	// The control tarball may be gzip, xz, or zstd (goreleaser/nfpm emit gzip or
+	// xz); each must round-trip to the same control stanza.
+	for _, tc := range []struct {
+		name   string
+		member string
+		comp   func([]byte) []byte
+	}{
+		{"gzip", "control.tar.gz", gzipBytes},
+		{"xz", "control.tar.xz", xzBytes},
+		{"zstd", "control.tar.zst", zstdBytes},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			deb := buildDeb("pkg", "9.9", "arm64", tc.member, tc.comp)
+			control, err := extractControl(deb)
+			if err != nil {
+				t.Fatalf("extractControl: %v", err)
+			}
+			fields := parseControlFields(control)
+			if fields["Package"] != "pkg" || fields["Version"] != "9.9" || fields["Architecture"] != "arm64" {
+				t.Errorf("fields = %v", fields)
+			}
+		})
+	}
+}
+
+func TestDebParseControlContinuationLines(t *testing.T) {
+	control := "Package: p\nVersion: 1\n" +
+		"Description: short\n very long\n .\n more\n" +
+		"Architecture: all\n"
+	f := parseControlFields(control)
+	if f["Package"] != "p" || f["Version"] != "1" || f["Architecture"] != "all" {
+		t.Errorf("continuation lines corrupted parse: %v", f)
+	}
+	if f["Description"] != "short" {
+		t.Errorf("Description folded continuation into value: %q", f["Description"])
+	}
+}
+
+func TestDebServeLocalIndex(t *testing.T) {
+	p := &Provider{}
+	reader := fakeDebReader{metas: []provider.DebMetadata{
+		{Name: "aaa", Version: "1.0", Architecture: "amd64", FilePath: "pool/aaa_1.0_amd64.deb",
+			Control: "Package: aaa\nVersion: 1.0\nArchitecture: amd64", Size: 100, MD5: "md5aaa", SHA256: "sha256aaa"},
+		{Name: "bbb", Version: "2.0", Architecture: "arm64", FilePath: "pool/bbb_2.0_arm64.deb",
+			Control: "Package: bbb\nVersion: 2.0\nArchitecture: arm64", Size: 200, MD5: "md5bbb", SHA256: "sha256bbb"},
+	}}
+
+	serve := func(path string) *httptest.ResponseRecorder {
+		w := httptest.NewRecorder()
+		r := httptest.NewRequest(http.MethodGet, "/"+path, nil)
+		if !p.ServeLocalIndex(w, r, reader, "myrepo", path) {
+			t.Fatalf("ServeLocalIndex returned false for %q", path)
+		}
+		return w
+	}
+
+	// Packages lists both packages with their apt fields.
+	w := serve("Packages")
+	body := w.Body.String()
+	if w.Code != 200 {
+		t.Fatalf("Packages code %d", w.Code)
+	}
+	for _, want := range []string{
+		"Package: aaa", "Package: bbb",
+		"Filename: pool/aaa_1.0_amd64.deb", "Size: 100", "MD5sum: md5aaa", "SHA256: sha256aaa",
+		"Filename: pool/bbb_2.0_arm64.deb", "Size: 200",
+	} {
+		if !strings.Contains(body, want) {
+			t.Errorf("Packages missing %q:\n%s", want, body)
+		}
+	}
+	// Stanzas are blank-line separated.
+	if !strings.Contains(body, "SHA256: sha256aaa\n\n") {
+		t.Errorf("stanzas not blank-line separated:\n%s", body)
+	}
+
+	// Packages.gz decompresses to exactly the plain Packages bytes.
+	w = serve("Packages.gz")
+	if w.Code != 200 {
+		t.Fatalf("Packages.gz code %d", w.Code)
+	}
+	zr, err := gzip.NewReader(bytes.NewReader(w.Body.Bytes()))
+	if err != nil {
+		t.Fatalf("Packages.gz not gzip: %v", err)
+	}
+	plain, _ := io.ReadAll(zr)
+	if !bytes.Equal(plain, []byte(body)) {
+		t.Error("Packages.gz does not decompress to Packages")
+	}
+
+	// Release lists arches and both index files under MD5Sum/SHA256.
+	w = serve("Release")
+	rel := w.Body.String()
+	if w.Code != 200 {
+		t.Fatalf("Release code %d", w.Code)
+	}
+	for _, want := range []string{"Date:", "Architectures: amd64 arm64", "Acquire-By-Hash: no", "MD5Sum:", "SHA256:", " Packages\n", " Packages.gz\n"} {
+		if !strings.Contains(rel, want) {
+			t.Errorf("Release missing %q:\n%s", want, rel)
+		}
+	}
+
+	// Unsigned trust model: no InRelease / Release.gpg served here.
+	for _, path := range []string{"InRelease", "Release.gpg", "pool/aaa_1.0_amd64.deb"} {
+		w := httptest.NewRecorder()
+		r := httptest.NewRequest(http.MethodGet, "/"+path, nil)
+		if p.ServeLocalIndex(w, r, reader, "myrepo", path) {
+			t.Errorf("ServeLocalIndex should return false for %q", path)
+		}
+	}
+}
+
+// Real apt appends the flat-repo dist "./" verbatim, so it requests "./Packages"
+// / "./Release" (curl pre-normalizes /./ which masks this). The handler must
+// collapse the dot-segment and return the same bytes as the un-prefixed request.
+func TestDebServeLocalIndexAptDotSegment(t *testing.T) {
+	p := &Provider{}
+	reader := fakeDebReader{metas: []provider.DebMetadata{
+		{Name: "aaa", Version: "1.0", Architecture: "amd64", FilePath: "pool/aaa_1.0_amd64.deb",
+			Control: "Package: aaa\nVersion: 1.0\nArchitecture: amd64", Size: 100, MD5: "md5aaa", SHA256: "sha256aaa"},
+	}}
+
+	serve := func(path string) *httptest.ResponseRecorder {
+		w := httptest.NewRecorder()
+		r := httptest.NewRequest(http.MethodGet, "/"+path, nil)
+		if !p.ServeLocalIndex(w, r, reader, "myrepo", path) {
+			t.Fatalf("ServeLocalIndex returned false for %q", path)
+		}
+		return w
+	}
+
+	// Packages is deterministic: require exact byte identity.
+	if plain, dotted := serve("Packages"), serve("./Packages"); plain.Code != 200 || dotted.Code != 200 {
+		t.Fatalf("Packages: plain=%d dotted=%d, want 200/200", plain.Code, dotted.Code)
+	} else if !bytes.Equal(plain.Body.Bytes(), dotted.Body.Bytes()) {
+		t.Error("./Packages body differs from Packages body")
+	}
+
+	// Release carries a Date: header stamped from time.Now(); compare the rest.
+	plain, dotted := serve("Release"), serve("./Release")
+	if plain.Code != 200 || dotted.Code != 200 {
+		t.Fatalf("Release: plain=%d dotted=%d, want 200/200", plain.Code, dotted.Code)
+	}
+	if stripDate(plain.Body.String()) != stripDate(dotted.Body.String()) {
+		t.Error("./Release body differs from Release body (ignoring Date)")
+	}
+}
+
+func stripDate(s string) string {
+	var out []string
+	for _, line := range strings.Split(s, "\n") {
+		if strings.HasPrefix(line, "Date:") {
+			continue
+		}
+		out = append(out, line)
+	}
+	return strings.Join(out, "\n")
+}
+
+func TestDebServeMetadataError(t *testing.T) {
+	p := &Provider{}
+	for _, path := range []string{"Packages", "Packages.gz", "Release"} {
+		w := httptest.NewRecorder()
+		r := httptest.NewRequest(http.MethodGet, "/"+path, nil)
+		p.ServeLocalIndex(w, r, errDebReader{}, "repo", path)
+		if w.Code != 500 {
+			t.Errorf("%s with failing reader = %d, want 500", path, w.Code)
+		}
+	}
+}
+
+func TestDebGenerateLocalIndexUnsupported(t *testing.T) {
+	if _, err := (&Provider{}).GenerateLocalIndex(context.Background(), fakeDebReader{}, "r", "Packages"); err == nil {
+		t.Error("expected unsupported error")
+	}
+}
+
+// buildDeb assembles an ar .deb whose control member uses the given name and
+// compressor, so the decompression branches can be exercised directly.
+func buildDeb(name, version, arch, member string, comp func([]byte) []byte) []byte {
+	control := "Package: " + name + "\nVersion: " + version + "\nArchitecture: " + arch + "\n"
+	controlTar := comp(tarSingle("./control", []byte(control)))
+
+	var buf bytes.Buffer
+	buf.WriteString("!<arch>\n")
+	arWrite(&buf, "debian-binary", []byte("2.0\n"))
+	arWrite(&buf, member, controlTar)
+	arWrite(&buf, "data.tar.gz", gzipBytes(tarSingle("./x", []byte("x"))))
+	return buf.Bytes()
+}
+
+func tarSingle(name string, data []byte) []byte {
+	var buf bytes.Buffer
+	tw := tar.NewWriter(&buf)
+	tw.WriteHeader(&tar.Header{Name: name, Mode: 0o644, Size: int64(len(data)), Typeflag: tar.TypeReg})
+	tw.Write(data)
+	tw.Close()
+	return buf.Bytes()
+}
+
+func arWrite(buf *bytes.Buffer, name string, data []byte) {
+	fmt.Fprintf(buf, "%-16s%-12s%-6s%-6s%-8s%-10d`\n", name, "0", "0", "0", "100644", len(data))
+	buf.Write(data)
+	if len(data)%2 == 1 {
+		buf.WriteByte('\n')
+	}
+}
+
+func xzBytes(data []byte) []byte {
+	var buf bytes.Buffer
+	w, _ := xz.NewWriter(&buf)
+	w.Write(data)
+	w.Close()
+	return buf.Bytes()
+}
+
+func zstdBytes(data []byte) []byte {
+	var buf bytes.Buffer
+	w, _ := zstd.NewWriter(&buf)
+	w.Write(data)
+	w.Close()
+	return buf.Bytes()
+}

internal/provider/deb/github.go

@@ -0,0 +1,724 @@
+package deb
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"regexp"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"git.unkin.net/unkin/artifactapi/internal/githubauth"
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// gitHubProvider is the process-wide singleton for github_deb. The background
+// Syncer binds its shared rate limiter and work queue onto this instance so the
+// request path and the syncer drive the same derive machinery.
+var gitHubProvider = newGitHubProvider()
+
+func init() {
+	provider.Register(gitHubProvider)
+}
+
+// Tuning knobs for the no-precache control fetch. A .deb is an ar archive whose
+// control.tar member sits right after the tiny debian-binary member, so a small
+// front prefix reliably covers it.
+const (
+	defaultHeaderRangeInitial = 32 << 10 // 32 KiB — covers control.tar of almost every .deb
+	defaultHeaderRangeMax     = 16 << 20 // 16 MiB — give up past this and skip the asset
+	defaultReleasePageCap     = 10       // 100 releases/page * 10 pages
+
+	defaultScanTimeout  = 10 * time.Minute
+	defaultServeTimeout = 30 * time.Second
+	defaultColdWait     = 8 * time.Second
+)
+
+// GitHubProvider is a metadata-only remote: it scans a GitHub repo's releases
+// for .deb assets, derives per-asset control metadata via a ranged prefix fetch
+// (never downloading whole packages), synthesizes a flat apt repository from that
+// cached metadata, and redirects package downloads to a backend "releases_remote"
+// (the generic github.com remote) that serves the actual bytes.
+type GitHubProvider struct {
+	client *http.Client
+
+	headerInitial int64
+	headerMax     int64
+	pageCap       int
+	scanTimeout   time.Duration
+	serveTimeout  time.Duration
+	coldWait      time.Duration
+
+	limiter *rate.Limiter
+	syncer  *Syncer
+
+	serverCred githubauth.Credential
+
+	mu       sync.Mutex
+	scanning map[string]bool
+	lastScan map[string]time.Time
+}
+
+func newGitHubProvider() *GitHubProvider {
+	return &GitHubProvider{
+		client:        &http.Client{},
+		headerInitial: defaultHeaderRangeInitial,
+		headerMax:     defaultHeaderRangeMax,
+		pageCap:       defaultReleasePageCap,
+		scanTimeout:   defaultScanTimeout,
+		serveTimeout:  defaultServeTimeout,
+		coldWait:      defaultColdWait,
+		scanning:      map[string]bool{},
+		lastScan:      map[string]time.Time{},
+	}
+}
+
+func (p *GitHubProvider) limiterWait(ctx context.Context) error {
+	if p.limiter == nil {
+		return nil
+	}
+	return p.limiter.Wait(ctx)
+}
+
+func (p *GitHubProvider) Type() models.PackageType { return models.PackageGitHubDeb }
+
+func (p *GitHubProvider) Classify(path string) provider.Mutability {
+	switch path {
+	case "Packages", "Packages.gz", "Release", "InRelease", "Release.gpg":
+		return provider.Mutable
+	}
+	return provider.Immutable
+}
+
+func (p *GitHubProvider) ContentType(path string) string {
+	switch {
+	case strings.HasSuffix(path, ".deb"):
+		return "application/vnd.debian.binary-package"
+	case strings.HasSuffix(path, ".gz"):
+		return "application/gzip"
+	case path == "Packages" || path == "Release" || path == "InRelease":
+		return "text/plain"
+	}
+	return "application/octet-stream"
+}
+
+func (p *GitHubProvider) UpstreamURL(remote models.Remote, path string) string {
+	return strings.TrimRight(remote.BaseURL, "/") + "/" + strings.TrimLeft(path, "/")
+}
+
+func (p *GitHubProvider) RewriteResponse(_ []byte, _ models.Remote, _ string) ([]byte, error) {
+	return nil, nil
+}
+
+func (p *GitHubProvider) AuthHeaders(ctx context.Context, remote models.Remote) (http.Header, error) {
+	return p.githubHeaders(ctx, remote, false)
+}
+
+// ServeRemote answers a request against a github_deb remote. It refreshes the
+// derived metadata (bounded by mutable_ttl), serves a synthesized flat apt repo
+// (Packages/Packages.gz/Release), 404s the signed index variants (the repo is
+// consumed via [trusted=yes]), and 302-redirects .deb downloads to the backend
+// releases_remote. Returns false only for paths it does not own.
+func (p *GitHubProvider) ServeRemote(w http.ResponseWriter, r *http.Request, remote models.Remote, reqPath, proxyBaseURL string, store provider.RemoteMetadataStore) bool {
+	p.onRequest(remote, store)
+
+	// apt appends the flat-repo dist "./" verbatim, so it asks for "./Packages"
+	// etc.; collapse the dot-segment before matching the synthesized index.
+	path := normalizeIndexPath(reqPath)
+
+	switch path {
+	case "Packages", "Packages.gz", "Release":
+		p.serveIndex(w, r, remote, path, store)
+		return true
+	case "InRelease", "Release.gpg":
+		// Unsigned flat repo: apt consumes it with [trusted=yes]. Signal absence
+		// so apt falls back to the plain Release without waiting on a signature.
+		http.Error(w, "not found", http.StatusNotFound)
+		return true
+	}
+
+	if strings.HasSuffix(path, ".deb") {
+		if remote.ReleasesRemote == "" {
+			http.Error(w, "github_deb remote has no releases_remote configured for downloads", http.StatusInternalServerError)
+			return true
+		}
+		loc := strings.TrimRight(proxyBaseURL, "/") + "/api/v1/remote/" + remote.ReleasesRemote + "/" + strings.TrimLeft(path, "/")
+		http.Redirect(w, r, loc, http.StatusFound)
+		return true
+	}
+
+	return false
+}
+
+func (p *GitHubProvider) serveIndex(w http.ResponseWriter, r *http.Request, remote models.Remote, path string, store provider.RemoteMetadataStore) {
+	// Serve on a context detached from the inbound request so a client disconnect
+	// never cancels the metadata DB read and surfaces as a 500.
+	sctx, cancel := context.WithTimeout(context.WithoutCancel(r.Context()), p.serveTimeout)
+	defer cancel()
+
+	if p.syncer != nil && !p.ensurePrimed(sctx, remote, store) {
+		w.Header().Set("Retry-After", "5")
+		http.Error(w, "metadata is being prepared, retry shortly", http.StatusServiceUnavailable)
+		return
+	}
+
+	reader, ok := store.(provider.DebMetadataReader)
+	if !ok {
+		http.Error(w, "deb metadata not available", http.StatusInternalServerError)
+		return
+	}
+	metas, err := reader.ListDebMetadataEntries(sctx, remote.Name)
+	if err != nil {
+		if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
+			http.Error(w, "metadata read canceled", http.StatusServiceUnavailable)
+			return
+		}
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	switch path {
+	case "Packages":
+		w.Header().Set("Content-Type", "text/plain")
+		w.WriteHeader(http.StatusOK)
+		w.Write(generatePackages(metas))
+	case "Packages.gz":
+		w.Header().Set("Content-Type", "application/gzip")
+		w.WriteHeader(http.StatusOK)
+		w.Write(gzipBytes(generatePackages(metas)))
+	case "Release":
+		w.Header().Set("Content-Type", "text/plain")
+		w.WriteHeader(http.StatusOK)
+		w.Write(generateRelease(metas))
+	}
+}
+
+// onRequest keeps a remote's derived metadata fresh off the request path.
+func (p *GitHubProvider) onRequest(remote models.Remote, store provider.RemoteMetadataStore) {
+	if p.syncer != nil {
+		p.syncer.enqueue(remote, false)
+		return
+	}
+	p.refresh(remote, store)
+}
+
+// ensurePrimed returns true once the remote has at least one cached row. On an
+// empty cache it enqueues a prime and polls briefly for it to land.
+func (p *GitHubProvider) ensurePrimed(ctx context.Context, remote models.Remote, store provider.RemoteMetadataStore) bool {
+	if !p.cacheEmpty(ctx, store, remote.Name) {
+		return true
+	}
+	if p.syncer != nil {
+		p.syncer.enqueue(remote, true)
+	}
+
+	deadline := time.Now().Add(p.coldWait)
+	for time.Now().Before(deadline) {
+		select {
+		case <-ctx.Done():
+			return false
+		case <-time.After(400 * time.Millisecond):
+		}
+		if !p.cacheEmpty(ctx, store, remote.Name) {
+			return true
+		}
+	}
+	return false
+}
+
+func (p *GitHubProvider) cacheEmpty(ctx context.Context, store provider.RemoteMetadataStore, name string) bool {
+	reader, ok := store.(provider.DebMetadataReader)
+	if !ok {
+		return false
+	}
+	rows, err := reader.ListDebMetadataEntries(ctx, name)
+	if err != nil {
+		return false
+	}
+	return len(rows) == 0
+}
+
+// refresh brings the derived metadata up to date without coupling the scan to
+// the inbound request (legacy inline path used without a syncer / in unit tests).
+func (p *GitHubProvider) refresh(remote models.Remote, store provider.RemoteMetadataStore) {
+	ttl := time.Duration(remote.MutableTTL) * time.Second
+	if ttl <= 0 {
+		ttl = 5 * time.Minute
+	}
+
+	p.mu.Lock()
+	last, ok := p.lastScan[remote.Name]
+	fresh := ok && time.Since(last) < ttl
+	if fresh || p.scanning[remote.Name] {
+		p.mu.Unlock()
+		return
+	}
+	p.scanning[remote.Name] = true
+	p.mu.Unlock()
+
+	if p.cacheEmpty(context.Background(), store, remote.Name) {
+		p.runScan(remote, store)
+		return
+	}
+	go p.runScan(remote, store)
+}
+
+func (p *GitHubProvider) runScan(remote models.Remote, store provider.RemoteMetadataStore) {
+	defer func() {
+		p.mu.Lock()
+		delete(p.scanning, remote.Name)
+		p.mu.Unlock()
+	}()
+
+	ctx, cancel := context.WithTimeout(context.Background(), p.scanTimeout)
+	defer cancel()
+
+	if err := p.scan(ctx, remote, store); err != nil {
+		slog.Error("github_deb: release scan failed", "remote", remote.Name, "error", err)
+		return
+	}
+
+	p.mu.Lock()
+	p.lastScan[remote.Name] = time.Now()
+	p.mu.Unlock()
+}
+
+// scan runs a full unconditional derive. Retained for the legacy inline refresh
+// path and existing tests; the syncer uses scanWithState.
+func (p *GitHubProvider) scan(ctx context.Context, remote models.Remote, store provider.RemoteMetadataStore) error {
+	_, _, err := p.scanWithState(ctx, remote, store, "")
+	return err
+}
+
+// scanWithState derives metadata incrementally. It sends the prior releases-list
+// ETag as a conditional request: a 304 means nothing changed. On a 200 it diffs
+// the release assets against the cache, derives only new/changed assets, prunes
+// assets that disappeared, and returns the new ETag.
+func (p *GitHubProvider) scanWithState(ctx context.Context, remote models.Remote, store provider.RemoteMetadataStore, etag string) (newEtag string, changed bool, err error) {
+	releases, newEtag, notModified, err := p.fetchReleases(ctx, remote, etag)
+	if err != nil {
+		return etag, false, err
+	}
+	if notModified {
+		return etag, false, nil
+	}
+
+	reader, ok := store.(provider.DebMetadataReader)
+	if !ok {
+		return newEtag, false, errors.New("store does not support deb metadata reads")
+	}
+	existing, err := reader.ListDebMetadataEntries(ctx, remote.Name)
+	if err != nil {
+		return newEtag, false, err
+	}
+	existingByPath := make(map[string]provider.DebMetadata, len(existing))
+	for _, m := range existing {
+		existingByPath[m.FilePath] = m
+	}
+
+	allow, err := compilePatterns(remote.Patterns)
+	if err != nil {
+		return newEtag, false, err
+	}
+
+	seen := map[string]bool{}
+	for _, rel := range releases {
+		if rel.Draft {
+			continue
+		}
+		for _, asset := range rel.Assets {
+			if !strings.HasSuffix(strings.ToLower(asset.Name), ".deb") {
+				continue
+			}
+			if !matchesAny(allow, asset.Name) {
+				continue
+			}
+			fp := assetPath(asset)
+			if fp == "" {
+				continue
+			}
+			seen[fp] = true
+
+			if cur, ok := existingByPath[fp]; ok {
+				if asset.Digest == "" || cur.ContentHash == asset.Digest {
+					continue
+				}
+				_ = store.DeleteDebMetadata(ctx, remote.Name, fp)
+			}
+
+			meta, err := p.deriveAsset(ctx, remote, asset, fp)
+			if err != nil {
+				slog.Warn("github_deb: derive asset failed", "remote", remote.Name, "asset", asset.Name, "error", err)
+				continue
+			}
+			if err := store.InsertDebMetadata(ctx, meta); err != nil {
+				slog.Error("github_deb: insert metadata failed", "remote", remote.Name, "asset", asset.Name, "error", err)
+				continue
+			}
+			slog.Info("github_deb: derived asset", "remote", remote.Name, "name", meta.Name, "version", meta.Version, "arch", meta.Architecture)
+		}
+	}
+
+	for fp := range existingByPath {
+		if !seen[fp] {
+			_ = store.DeleteDebMetadata(ctx, remote.Name, fp)
+		}
+	}
+	return newEtag, true, nil
+}
+
+type ghRelease struct {
+	TagName string    `json:"tag_name"`
+	Draft   bool      `json:"draft"`
+	Assets  []ghAsset `json:"assets"`
+}
+
+type ghAsset struct {
+	Name               string `json:"name"`
+	Size               int64  `json:"size"`
+	BrowserDownloadURL string `json:"browser_download_url"`
+	Digest             string `json:"digest"`
+}
+
+// fetchReleases lists a repo's releases, sending the prior ETag as If-None-Match
+// on page 1 so an unchanged repo short-circuits to notModified. Every call waits
+// on the shared limiter first.
+func (p *GitHubProvider) fetchReleases(ctx context.Context, remote models.Remote, etag string) (all []ghRelease, newEtag string, notModified bool, err error) {
+	base := strings.TrimRight(remote.BaseURL, "/") + "/releases"
+	for page := 1; page <= p.pageCap; page++ {
+		u := fmt.Sprintf("%s?per_page=100&page=%d", base, page)
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
+		if err != nil {
+			return nil, "", false, err
+		}
+		hdr, err := p.githubHeaders(ctx, remote, true)
+		if err != nil {
+			return nil, "", false, err
+		}
+		copyHeaders(req, hdr)
+		if page == 1 && etag != "" {
+			req.Header.Set("If-None-Match", etag)
+		}
+
+		if err := p.limiterWait(ctx); err != nil {
+			return nil, "", false, err
+		}
+		resp, err := p.client.Do(req)
+		if err != nil {
+			return nil, "", false, err
+		}
+		if page == 1 && resp.StatusCode == http.StatusNotModified {
+			io.Copy(io.Discard, resp.Body)
+			resp.Body.Close()
+			return nil, etag, true, nil
+		}
+		body, err := io.ReadAll(resp.Body)
+		respEtag := resp.Header.Get("ETag")
+		resp.Body.Close()
+		if err != nil {
+			return nil, "", false, err
+		}
+		if resp.StatusCode != http.StatusOK {
+			return nil, "", false, fmt.Errorf("github releases API %s: status %d", u, resp.StatusCode)
+		}
+		if page == 1 {
+			newEtag = respEtag
+		}
+		var releases []ghRelease
+		if err := json.Unmarshal(body, &releases); err != nil {
+			return nil, "", false, fmt.Errorf("decode releases: %w", err)
+		}
+		if len(releases) == 0 {
+			break
+		}
+		all = append(all, releases...)
+		if len(releases) < 100 {
+			break
+		}
+	}
+	return all, newEtag, false, nil
+}
+
+func (p *GitHubProvider) deriveAsset(ctx context.Context, remote models.Remote, asset ghAsset, fp string) (*provider.DebMetadata, error) {
+	control, err := p.fetchControl(ctx, remote, asset.BrowserDownloadURL)
+	if err != nil {
+		return nil, err
+	}
+	fields := parseControlFields(control)
+
+	meta := &provider.DebMetadata{
+		RepoName:     remote.Name,
+		FilePath:     fp,
+		Name:         fields["Package"],
+		Version:      fields["Version"],
+		Architecture: fields["Architecture"],
+		Control:      strings.TrimRight(control, "\n"),
+		Size:         asset.Size,
+	}
+	if meta.Name == "" {
+		return nil, errors.New("control missing Package field")
+	}
+
+	// The Packages SHA256 must be the sha256 of the whole .deb. Prefer GitHub's
+	// asset digest so we never download the body; only when it is absent (or not
+	// sha256) do we stream the asset once. MD5sum is left unset — apt verifies the
+	// download against SHA256 alone under [trusted=yes].
+	if h, ok := sha256FromDigest(asset.Digest); ok {
+		meta.ContentHash = "sha256:" + h
+		meta.SHA256 = h
+	} else {
+		h, err := p.computeSHA256(ctx, remote, asset.BrowserDownloadURL)
+		if err != nil {
+			return nil, fmt.Errorf("compute sha256: %w", err)
+		}
+		meta.ContentHash = "sha256:" + h
+		meta.SHA256 = h
+	}
+
+	return meta, nil
+}
+
+// fetchControl pulls only the front of the .deb with a ranged GET and extracts
+// the control paragraph from it. control.tar sits right after the tiny
+// debian-binary member, so a small prefix suffices; a prefix that truncates the
+// control member doubles the range and retries.
+func (p *GitHubProvider) fetchControl(ctx context.Context, remote models.Remote, downloadURL string) (string, error) {
+	n := p.headerInitial
+	for {
+		body, full, err := p.rangeGet(ctx, remote, downloadURL, n)
+		if err != nil {
+			return "", err
+		}
+		control, complete, perr := controlFromPrefix(body)
+		if perr != nil {
+			return "", fmt.Errorf("parse deb control: %w", perr)
+		}
+		if complete {
+			return control, nil
+		}
+		if full || n >= p.headerMax {
+			return "", fmt.Errorf("control.tar not found within %d bytes of %s", n, downloadURL)
+		}
+		n *= 2
+		if n > p.headerMax {
+			n = p.headerMax
+		}
+	}
+}
+
+// controlFromPrefix parses the ar members present in a front prefix of a .deb.
+// It returns the ./control paragraph once control.tar.* is fully covered
+// (complete=true); a prefix too short to cover it returns complete=false so the
+// caller can widen the range. Later members (data.tar.*) are ignored.
+func controlFromPrefix(prefix []byte) (control string, complete bool, err error) {
+	const magic = "!<arch>\n"
+	if len(prefix) < len(magic) {
+		return "", false, nil
+	}
+	if string(prefix[:len(magic)]) != magic {
+		return "", false, errors.New("not an ar archive")
+	}
+	off := len(magic)
+	for {
+		if off+60 > len(prefix) {
+			return "", false, nil
+		}
+		hdr := prefix[off : off+60]
+		off += 60
+		name := strings.TrimSuffix(strings.TrimRight(string(hdr[0:16]), " "), "/")
+		size, err := strconv.ParseInt(strings.TrimSpace(string(hdr[48:58])), 10, 64)
+		if err != nil {
+			return "", false, fmt.Errorf("bad ar size for %q: %w", name, err)
+		}
+		if strings.HasPrefix(name, "control.tar") {
+			if off+int(size) > len(prefix) {
+				return "", false, nil
+			}
+			tarBytes, err := decompress(name, prefix[off:off+int(size)])
+			if err != nil {
+				return "", false, err
+			}
+			c, err := readControlParagraph(tarBytes)
+			if err != nil {
+				return "", false, err
+			}
+			return c, true, nil
+		}
+		if off+int(size) > len(prefix) {
+			return "", false, nil
+		}
+		off += int(size)
+		if size%2 == 1 {
+			off++
+		}
+	}
+}
+
+// rangeGet returns the first n bytes of downloadURL. full is true when the
+// response body was shorter than n (i.e. we already have the whole object).
+func (p *GitHubProvider) rangeGet(ctx context.Context, remote models.Remote, downloadURL string, n int64) ([]byte, bool, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, downloadURL, nil)
+	if err != nil {
+		return nil, false, err
+	}
+	hdr, err := p.githubHeaders(ctx, remote, false)
+	if err != nil {
+		return nil, false, err
+	}
+	copyHeaders(req, hdr)
+	req.Header.Set("Range", fmt.Sprintf("bytes=0-%d", n-1))
+
+	if err := p.limiterWait(ctx); err != nil {
+		return nil, false, err
+	}
+	resp, err := p.client.Do(req)
+	if err != nil {
+		return nil, false, err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusPartialContent {
+		return nil, false, fmt.Errorf("range GET %s: status %d", downloadURL, resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(io.LimitReader(resp.Body, n))
+	if err != nil {
+		return nil, false, err
+	}
+	full := int64(len(body)) < n
+	return body, full, nil
+}
+
+func (p *GitHubProvider) computeSHA256(ctx context.Context, remote models.Remote, downloadURL string) (string, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, downloadURL, nil)
+	if err != nil {
+		return "", err
+	}
+	hdr, err := p.githubHeaders(ctx, remote, false)
+	if err != nil {
+		return "", err
+	}
+	copyHeaders(req, hdr)
+
+	if err := p.limiterWait(ctx); err != nil {
+		return "", err
+	}
+	resp, err := p.client.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return "", fmt.Errorf("GET %s: status %d", downloadURL, resp.StatusCode)
+	}
+
+	h := sha256.New()
+	if _, err := io.Copy(h, resp.Body); err != nil {
+		return "", err
+	}
+	return hex.EncodeToString(h.Sum(nil)), nil
+}
+
+// assetPath is the package's location relative to github.com — the path the
+// backend releases_remote (base https://github.com) proxies. It doubles as the
+// deb_metadata key and the Filename field in the Packages index, so a .deb
+// download resolves back to this remote and redirects to the backend.
+func assetPath(asset ghAsset) string {
+	u, err := url.Parse(asset.BrowserDownloadURL)
+	if err != nil {
+		return ""
+	}
+	return strings.TrimPrefix(u.Path, "/")
+}
+
+func sha256FromDigest(digest string) (string, bool) {
+	if strings.HasPrefix(digest, "sha256:") {
+		return strings.TrimPrefix(digest, "sha256:"), true
+	}
+	return "", false
+}
+
+// githubHeaders builds the outbound headers for a GitHub request, attaching a
+// bearer credential when one is available. A per-remote credential wins; absent
+// that, the process-wide server credential is used; absent both, the request is
+// unauthenticated.
+func (p *GitHubProvider) githubHeaders(ctx context.Context, remote models.Remote, api bool) (http.Header, error) {
+	h := http.Header{}
+	if api {
+		h.Set("Accept", "application/vnd.github+json")
+		h.Set("X-GitHub-Api-Version", "2022-11-28")
+	}
+	tok, err := p.githubToken(ctx, remote)
+	if err != nil {
+		return nil, err
+	}
+	if tok != "" {
+		h.Set("Authorization", "Bearer "+tok)
+	}
+	return h, nil
+}
+
+// githubToken resolves the bearer token for a remote. Precedence: a per-remote
+// credential (password, then username) overrides the server credential.
+func (p *GitHubProvider) githubToken(ctx context.Context, remote models.Remote) (string, error) {
+	if remote.Password != "" {
+		return remote.Password, nil
+	}
+	if remote.Username != "" {
+		return remote.Username, nil
+	}
+	if c := p.serverCredential(); c != nil {
+		return c.Token(ctx)
+	}
+	return "", nil
+}
+
+func (p *GitHubProvider) serverCredential() githubauth.Credential {
+	if p.serverCred != nil {
+		return p.serverCred
+	}
+	return githubauth.Server()
+}
+
+func copyHeaders(req *http.Request, h http.Header) {
+	for k, vals := range h {
+		for _, v := range vals {
+			req.Header.Add(k, v)
+		}
+	}
+}
+
+func compilePatterns(patterns []string) ([]*regexp.Regexp, error) {
+	var out []*regexp.Regexp
+	for _, p := range patterns {
+		re, err := regexp.Compile(p)
+		if err != nil {
+			return nil, fmt.Errorf("invalid pattern %q: %w", p, err)
+		}
+		out = append(out, re)
+	}
+	return out, nil
+}
+
+func matchesAny(res []*regexp.Regexp, s string) bool {
+	if len(res) == 0 {
+		return true
+	}
+	for _, re := range res {
+		if re.MatchString(s) {
+			return true
+		}
+	}
+	return false
+}

internal/provider/deb/github_test.go

@@ -0,0 +1,462 @@
+package deb
+
+import (
+	"bytes"
+	"compress/gzip"
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// fakeStore is an in-memory provider.RemoteMetadataStore + DebMetadataReader
+// keyed by file_path, mirroring the (repo_name, file_path) uniqueness of the
+// real deb_metadata table.
+type fakeStore struct {
+	mu   sync.Mutex
+	rows map[string]provider.DebMetadata
+}
+
+func newFakeStore() *fakeStore { return &fakeStore{rows: map[string]provider.DebMetadata{}} }
+
+func (f *fakeStore) InsertDebMetadata(_ context.Context, m *provider.DebMetadata) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if _, ok := f.rows[m.FilePath]; ok {
+		return nil // ON CONFLICT DO NOTHING
+	}
+	f.rows[m.FilePath] = *m
+	return nil
+}
+
+func (f *fakeStore) DeleteDebMetadata(_ context.Context, _, filePath string) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	delete(f.rows, filePath)
+	return nil
+}
+
+func (f *fakeStore) InsertRPMMetadata(context.Context, *provider.RPMMetadata) error { return nil }
+func (f *fakeStore) DeleteRPMMetadata(context.Context, string, string) error        { return nil }
+func (f *fakeStore) ListRPMMetadataEntries(context.Context, string) ([]provider.RPMMetadata, error) {
+	return nil, nil
+}
+
+func (f *fakeStore) ListDebMetadataEntries(ctx context.Context, _ string) ([]provider.DebMetadata, error) {
+	if err := ctx.Err(); err != nil {
+		return nil, err
+	}
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	out := make([]provider.DebMetadata, 0, len(f.rows))
+	for _, m := range f.rows {
+		out = append(out, m)
+	}
+	return out, nil
+}
+
+// githubFixture serves the releases API and the .deb asset downloads (with Range
+// support) for a set of packages. digest controls whether the asset carries a
+// sha256 digest (no-download path) or not (compute path).
+type githubFixture struct {
+	srv         *httptest.Server
+	debBytes    map[string][]byte
+	rangeHit    map[string]int
+	fullHit     map[string]int
+	etag        string
+	releasesHit int
+	notModHit   int
+	releaseAuth string
+	assetAuth   string
+	mu          sync.Mutex
+}
+
+func newGitHubFixture(t *testing.T, withDigest bool) *githubFixture {
+	t.Helper()
+	f := &githubFixture{
+		debBytes: map[string][]byte{},
+		rangeHit: map[string]int{},
+		fullHit:  map[string]int{},
+	}
+	f.debBytes["demo_1.2-3_amd64.deb"] = testsupport.MinimalDeb("demo", "1.2-3", "amd64")
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/repos/acme/tools/releases", func(w http.ResponseWriter, r *http.Request) {
+		page := r.URL.Query().Get("page")
+		if page != "" && page != "1" {
+			w.Write([]byte("[]"))
+			return
+		}
+		f.mu.Lock()
+		f.releasesHit++
+		f.releaseAuth = r.Header.Get("Authorization")
+		etag := f.etag
+		if etag != "" && r.Header.Get("If-None-Match") == etag {
+			f.notModHit++
+			f.mu.Unlock()
+			w.WriteHeader(http.StatusNotModified)
+			return
+		}
+		f.mu.Unlock()
+		if etag != "" {
+			w.Header().Set("ETag", etag)
+		}
+		var assets []map[string]any
+		for name := range f.debBytes {
+			a := map[string]any{
+				"name":                 name,
+				"size":                 len(f.debBytes[name]),
+				"browser_download_url": f.srv.URL + "/acme/tools/releases/download/v1.2-3/" + name,
+			}
+			if withDigest {
+				sum := sha256.Sum256(f.debBytes[name])
+				a["digest"] = "sha256:" + hex.EncodeToString(sum[:])
+			}
+			assets = append(assets, a)
+		}
+		rel := []map[string]any{{"tag_name": "v1.2-3", "draft": false, "assets": assets}}
+		json.NewEncoder(w).Encode(rel)
+	})
+	mux.HandleFunc("/acme/tools/releases/download/", func(w http.ResponseWriter, r *http.Request) {
+		name := r.URL.Path[strings.LastIndex(r.URL.Path, "/")+1:]
+		body, ok := f.debBytes[name]
+		if !ok {
+			http.Error(w, "not found", 404)
+			return
+		}
+		rng := r.Header.Get("Range")
+		f.mu.Lock()
+		f.assetAuth = r.Header.Get("Authorization")
+		if rng != "" {
+			f.rangeHit[name]++
+		} else {
+			f.fullHit[name]++
+		}
+		f.mu.Unlock()
+
+		if rng == "" {
+			w.WriteHeader(200)
+			w.Write(body)
+			return
+		}
+		var end int
+		fmt.Sscanf(rng, "bytes=0-%d", &end)
+		if end >= len(body)-1 {
+			end = len(body) - 1
+		}
+		w.Header().Set("Content-Range", fmt.Sprintf("bytes 0-%d/%d", end, len(body)))
+		w.Header().Set("Content-Length", strconv.Itoa(end+1))
+		w.WriteHeader(http.StatusPartialContent)
+		w.Write(body[:end+1])
+	})
+	f.srv = httptest.NewServer(mux)
+	t.Cleanup(f.srv.Close)
+	return f
+}
+
+func (f *githubFixture) remote() models.Remote {
+	return models.Remote{
+		Name:           "acme-deb",
+		PackageType:    models.PackageGitHubDeb,
+		BaseURL:        f.srv.URL + "/repos/acme/tools",
+		ReleasesRemote: "github",
+		MutableTTL:     3600,
+	}
+}
+
+func newTestProvider() *GitHubProvider {
+	p := newGitHubProvider()
+	p.headerInitial = 32 // force the ranged-fetch retry loop against the tiny fixture
+	p.headerMax = 1 << 20
+	return p
+}
+
+const demoPath = "acme/tools/releases/download/v1.2-3/demo_1.2-3_amd64.deb"
+
+func TestGitHubScanDerivesControlFromPrefixAndDigest(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+
+	if err := p.scan(context.Background(), fx.remote(), store); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+
+	metas, _ := store.ListDebMetadataEntries(context.Background(), "acme-deb")
+	if len(metas) != 1 {
+		t.Fatalf("want 1 metadata row, got %d", len(metas))
+	}
+	m := metas[0]
+	if m.Name != "demo" || m.Version != "1.2-3" || m.Architecture != "amd64" {
+		t.Fatalf("bad control fields: %+v", m)
+	}
+	if m.FilePath != demoPath {
+		t.Fatalf("FilePath = %q, want %q", m.FilePath, demoPath)
+	}
+	if int(m.Size) != len(fx.debBytes["demo_1.2-3_amd64.deb"]) {
+		t.Fatalf("Size = %d, want %d", m.Size, len(fx.debBytes["demo_1.2-3_amd64.deb"]))
+	}
+	sum := sha256.Sum256(fx.debBytes["demo_1.2-3_amd64.deb"])
+	if m.SHA256 != hex.EncodeToString(sum[:]) {
+		t.Fatalf("SHA256 = %q, want digest", m.SHA256)
+	}
+	if m.ContentHash != "sha256:"+hex.EncodeToString(sum[:]) {
+		t.Fatalf("ContentHash = %q", m.ContentHash)
+	}
+	if m.MD5 != "" {
+		t.Fatalf("MD5 should be unset for metadata-only derive, got %q", m.MD5)
+	}
+	if fx.fullHit["demo_1.2-3_amd64.deb"] != 0 {
+		t.Fatalf("expected no full download when digest present, got %d", fx.fullHit["demo_1.2-3_amd64.deb"])
+	}
+	if fx.rangeHit["demo_1.2-3_amd64.deb"] == 0 {
+		t.Fatalf("expected ranged control fetch")
+	}
+	if !strings.Contains(m.Control, "Package: demo") {
+		t.Fatalf("raw control not captured: %q", m.Control)
+	}
+}
+
+func TestGitHubChecksumComputedWhenDigestAbsent(t *testing.T) {
+	fx := newGitHubFixture(t, false)
+	p := newTestProvider()
+	store := newFakeStore()
+
+	if err := p.scan(context.Background(), fx.remote(), store); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+	metas, _ := store.ListDebMetadataEntries(context.Background(), "acme-deb")
+	if len(metas) != 1 {
+		t.Fatalf("want 1 row, got %d", len(metas))
+	}
+	sum := sha256.Sum256(fx.debBytes["demo_1.2-3_amd64.deb"])
+	if metas[0].SHA256 != hex.EncodeToString(sum[:]) {
+		t.Fatalf("computed checksum mismatch: %q", metas[0].SHA256)
+	}
+	if fx.fullHit["demo_1.2-3_amd64.deb"] == 0 {
+		t.Fatalf("expected a full download to compute sha256 when digest absent")
+	}
+}
+
+func TestGitHubServeRemoteIndexAndRedirect(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+	const proxyBase = "https://artifactapi.example"
+
+	// Release is served and triggers the initial scan.
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-deb/Release", nil)
+	if !p.ServeRemote(rec, req, remote, "Release", proxyBase, store) {
+		t.Fatal("ServeRemote did not handle Release")
+	}
+	if rec.Code != 200 || !strings.Contains(rec.Body.String(), "Architectures:") {
+		t.Fatalf("Release bad: code=%d body=%s", rec.Code, rec.Body.String())
+	}
+	if !strings.Contains(rec.Body.String(), "amd64") {
+		t.Fatalf("Release missing arch: %s", rec.Body.String())
+	}
+
+	// Packages carries the package with a Filename that is the github-relative
+	// download path (so it resolves back to this remote and redirects).
+	rec = httptest.NewRecorder()
+	req = httptest.NewRequest(http.MethodGet, "/x", nil)
+	if !p.ServeRemote(rec, req, remote, "Packages", proxyBase, store) {
+		t.Fatal("ServeRemote did not handle Packages")
+	}
+	pkgs := rec.Body.String()
+	if !strings.Contains(pkgs, "Package: demo") {
+		t.Fatalf("Packages missing package: %s", pkgs)
+	}
+	if !strings.Contains(pkgs, "Filename: "+demoPath) {
+		t.Fatalf("Packages missing/incorrect Filename: %s", pkgs)
+	}
+	if !strings.Contains(pkgs, "SHA256: ") {
+		t.Fatalf("Packages missing SHA256: %s", pkgs)
+	}
+	if strings.Contains(pkgs, "MD5sum:") {
+		t.Fatalf("Packages should omit empty MD5sum: %s", pkgs)
+	}
+
+	// Packages.gz decompresses to the same content.
+	rec = httptest.NewRecorder()
+	req = httptest.NewRequest(http.MethodGet, "/x", nil)
+	if !p.ServeRemote(rec, req, remote, "Packages.gz", proxyBase, store) {
+		t.Fatal("ServeRemote did not handle Packages.gz")
+	}
+	gz, err := gzip.NewReader(rec.Body)
+	if err != nil {
+		t.Fatalf("gzip: %v", err)
+	}
+	unz, _ := io.ReadAll(gz)
+	if !strings.Contains(string(unz), "Package: demo") {
+		t.Fatalf("Packages.gz missing package: %s", unz)
+	}
+
+	// InRelease/Release.gpg 404 (unsigned, consumed via [trusted=yes]).
+	for _, sp := range []string{"InRelease", "Release.gpg"} {
+		rec = httptest.NewRecorder()
+		req = httptest.NewRequest(http.MethodGet, "/x", nil)
+		if !p.ServeRemote(rec, req, remote, sp, proxyBase, store) {
+			t.Fatalf("ServeRemote did not handle %s", sp)
+		}
+		if rec.Code != http.StatusNotFound {
+			t.Fatalf("%s want 404, got %d", sp, rec.Code)
+		}
+	}
+
+	// A .deb request redirects to the backend releases_remote.
+	rec = httptest.NewRecorder()
+	req = httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-deb/"+demoPath, nil)
+	if !p.ServeRemote(rec, req, remote, demoPath, proxyBase, store) {
+		t.Fatal("ServeRemote did not handle .deb")
+	}
+	if rec.Code != http.StatusFound {
+		t.Fatalf("want 302, got %d", rec.Code)
+	}
+	wantLoc := proxyBase + "/api/v1/remote/github/" + demoPath
+	if got := rec.Header().Get("Location"); got != wantLoc {
+		t.Fatalf("Location = %q, want %q", got, wantLoc)
+	}
+}
+
+// Real apt appends the flat-repo dist "./" verbatim, so the metadata-only remote
+// receives "./Packages" / "./Release"; ServeRemote must collapse the dot-segment
+// and synthesize the same index as the un-prefixed request.
+func TestGitHubServeRemoteAptDotSegment(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+	const proxyBase = "https://artifactapi.example"
+
+	serve := func(path string) *httptest.ResponseRecorder {
+		rec := httptest.NewRecorder()
+		req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-deb/"+path, nil)
+		if !p.ServeRemote(rec, req, remote, path, proxyBase, store) {
+			t.Fatalf("ServeRemote did not handle %q", path)
+		}
+		return rec
+	}
+
+	// Packages is deterministic: byte-identical to the un-prefixed request.
+	plain, dotted := serve("Packages"), serve("./Packages")
+	if plain.Code != 200 || dotted.Code != 200 {
+		t.Fatalf("Packages: plain=%d dotted=%d, want 200/200", plain.Code, dotted.Code)
+	}
+	if !strings.Contains(dotted.Body.String(), "Package: demo") {
+		t.Fatalf("./Packages missing synthesized body: %s", dotted.Body.String())
+	}
+	if !bytes.Equal(plain.Body.Bytes(), dotted.Body.Bytes()) {
+		t.Error("./Packages body differs from Packages body")
+	}
+
+	// Release carries a time.Now() Date: header; compare the rest.
+	rPlain, rDotted := serve("Release"), serve("./Release")
+	if rPlain.Code != 200 || rDotted.Code != 200 {
+		t.Fatalf("Release: plain=%d dotted=%d, want 200/200", rPlain.Code, rDotted.Code)
+	}
+	if stripDate(rPlain.Body.String()) != stripDate(rDotted.Body.String()) {
+		t.Error("./Release body differs from Release body (ignoring Date)")
+	}
+}
+
+// A canceled inbound request must still serve the warm cache (detached context),
+// not turn the metadata read into a 500.
+func TestGitHubServeRemoteCanceledRequestServesCache(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+
+	if err := p.scan(context.Background(), remote, store); err != nil {
+		t.Fatalf("warm scan: %v", err)
+	}
+	p.mu.Lock()
+	p.lastScan[remote.Name] = time.Now()
+	p.mu.Unlock()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-deb/Packages", nil).WithContext(ctx)
+
+	if !p.ServeRemote(rec, req, remote, "Packages", "https://x", store) {
+		t.Fatal("ServeRemote did not handle Packages")
+	}
+	if rec.Code != http.StatusOK {
+		t.Fatalf("canceled request must serve cache, not error; got code=%d body=%s", rec.Code, rec.Body.String())
+	}
+	if !strings.Contains(rec.Body.String(), "Package: demo") {
+		t.Fatalf("expected Packages served from cache, got %s", rec.Body.String())
+	}
+}
+
+func TestGitHubServeRemoteRedirectRequiresReleasesRemote(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+	remote.ReleasesRemote = ""
+
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/x", nil)
+	if !p.ServeRemote(rec, req, remote, demoPath, "https://x", store) {
+		t.Fatal("expected handled")
+	}
+	if rec.Code != http.StatusInternalServerError {
+		t.Fatalf("want 500 when releases_remote unset, got %d", rec.Code)
+	}
+}
+
+func TestGitHubScanPrunesRemovedAssets(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	store := newFakeStore()
+
+	if err := p.scan(context.Background(), fx.remote(), store); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+	if rows, _ := store.ListDebMetadataEntries(context.Background(), "acme-deb"); len(rows) != 1 {
+		t.Fatalf("want 1 row after first scan, got %d", len(rows))
+	}
+
+	delete(fx.debBytes, "demo_1.2-3_amd64.deb")
+	if err := p.scan(context.Background(), fx.remote(), store); err != nil {
+		t.Fatalf("rescan: %v", err)
+	}
+	if rows, _ := store.ListDebMetadataEntries(context.Background(), "acme-deb"); len(rows) != 0 {
+		t.Fatalf("want 0 rows after prune, got %d", len(rows))
+	}
+}
+
+func TestGitHubAssetPatternFilter(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.debBytes["other_9_arm64.deb"] = testsupport.MinimalDeb("other", "9", "arm64")
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+	remote.Patterns = []string{`^demo_.*_amd64\.deb$`}
+
+	if err := p.scan(context.Background(), remote, store); err != nil {
+		t.Fatalf("scan: %v", err)
+	}
+	rows, _ := store.ListDebMetadataEntries(context.Background(), "acme-deb")
+	if len(rows) != 1 || rows[0].Name != "demo" {
+		t.Fatalf("pattern filter failed, rows=%+v", rows)
+	}
+}

internal/provider/deb/syncer.go

@@ -0,0 +1,238 @@
+package deb
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/hex"
+	"log/slog"
+	"os"
+	"sync"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+const (
+	syncLeaseDuration    = 15 * time.Minute
+	defaultSyncFreshness = 5 * time.Minute
+	jobQueueDepth        = 256
+)
+
+// SyncStore is the persistence surface the deb syncer needs: the metadata cache
+// it primes plus the shared sync-state coordination (remote enumeration and the
+// per-remote lease). *database.DB satisfies it.
+type SyncStore interface {
+	provider.RemoteMetadataStore
+	ListGitHubDebRemotes(ctx context.Context) ([]models.Remote, error)
+	ClaimGitHubDebSyncLease(ctx context.Context, remoteName, owner string, freshness, lease time.Duration) (claimed bool, etag string, err error)
+	ReleaseGitHubDebSyncLease(ctx context.Context, remoteName, owner, etag string, syncedAt time.Time) error
+}
+
+// SyncConfig tunes the shared syncer. Zero values fall back to safe defaults.
+type SyncConfig struct {
+	RatePerSec   float64
+	Burst        int
+	Workers      int
+	PollInterval time.Duration
+}
+
+type syncJob struct {
+	remote models.Remote
+	prime  bool
+}
+
+// Syncer is the single per-process background worker that keeps every github_deb
+// remote's derived metadata fresh. It owns a deduped work queue, a pool of
+// workers, and a global token-bucket rate limiter shared across all remotes and
+// bound onto the github_deb provider. Periodic checks are gated by a shared DB
+// lease so, across replicas, only one performs each scan.
+type Syncer struct {
+	store   SyncStore
+	prov    *GitHubProvider
+	limiter *rate.Limiter
+	cfg     SyncConfig
+	owner   string
+
+	jobs   chan syncJob
+	mu     sync.Mutex
+	active map[string]bool
+}
+
+// NewSyncer builds the syncer bound to the process-wide github_deb provider
+// singleton. Call Run to start it.
+func NewSyncer(store SyncStore, cfg SyncConfig) *Syncer {
+	return newSyncer(store, gitHubProvider, cfg)
+}
+
+func newSyncer(store SyncStore, prov *GitHubProvider, cfg SyncConfig) *Syncer {
+	if cfg.RatePerSec <= 0 {
+		cfg.RatePerSec = 1
+	}
+	if cfg.Burst <= 0 {
+		cfg.Burst = 5
+	}
+	if cfg.Workers <= 0 {
+		cfg.Workers = 3
+	}
+	if cfg.PollInterval <= 0 {
+		cfg.PollInterval = 60 * time.Second
+	}
+
+	lim := rate.NewLimiter(rate.Limit(cfg.RatePerSec), cfg.Burst)
+	s := &Syncer{
+		store:   store,
+		prov:    prov,
+		limiter: lim,
+		cfg:     cfg,
+		owner:   leaseOwner(),
+		jobs:    make(chan syncJob, jobQueueDepth),
+		active:  map[string]bool{},
+	}
+	prov.limiter = lim
+	prov.syncer = s
+	return s
+}
+
+// Run starts the worker pool and the periodic scheduler and blocks until ctx is
+// canceled, at which point it drains in-flight scans and returns.
+func (s *Syncer) Run(ctx context.Context) {
+	slog.Info("github_deb syncer started",
+		"rate_per_sec", s.cfg.RatePerSec, "burst", s.cfg.Burst,
+		"workers", s.cfg.Workers, "poll_interval", s.cfg.PollInterval, "owner", s.owner)
+
+	var wg sync.WaitGroup
+	for i := 0; i < s.cfg.Workers; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			s.worker(ctx)
+		}()
+	}
+
+	ticker := time.NewTicker(s.cfg.PollInterval)
+	defer ticker.Stop()
+
+	s.schedule(ctx)
+	for {
+		select {
+		case <-ctx.Done():
+			wg.Wait()
+			slog.Info("github_deb syncer stopped")
+			return
+		case <-ticker.C:
+			s.schedule(ctx)
+		}
+	}
+}
+
+// schedule enqueues a periodic check for every github_deb remote. The DB lease
+// enforces the per-remote mutable_ttl cadence and cross-replica coordination.
+func (s *Syncer) schedule(ctx context.Context) {
+	remotes, err := s.store.ListGitHubDebRemotes(ctx)
+	if err != nil {
+		slog.Error("github_deb syncer: list remotes", "error", err)
+		return
+	}
+	for _, r := range remotes {
+		s.enqueue(r, false)
+	}
+}
+
+// EnqueuePrime queues an immediate background prime for a freshly created remote.
+func (s *Syncer) EnqueuePrime(remote models.Remote) {
+	if s == nil {
+		return
+	}
+	s.enqueue(remote, true)
+}
+
+// enqueue adds a job unless the remote is already queued or in-flight, coalescing
+// duplicate requests down to one scan. It never blocks.
+func (s *Syncer) enqueue(remote models.Remote, prime bool) {
+	s.mu.Lock()
+	if s.active[remote.Name] {
+		s.mu.Unlock()
+		return
+	}
+	s.active[remote.Name] = true
+	s.mu.Unlock()
+
+	select {
+	case s.jobs <- syncJob{remote: remote, prime: prime}:
+	default:
+		s.mu.Lock()
+		delete(s.active, remote.Name)
+		s.mu.Unlock()
+	}
+}
+
+func (s *Syncer) worker(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case job := <-s.jobs:
+			s.process(ctx, job)
+		}
+	}
+}
+
+// process claims the shared lease and, if won, runs an incremental scan. Losing
+// the claim (another replica scanning, or not yet due) is a no-op.
+func (s *Syncer) process(ctx context.Context, job syncJob) {
+	defer func() {
+		s.mu.Lock()
+		delete(s.active, job.remote.Name)
+		s.mu.Unlock()
+	}()
+
+	freshness := time.Duration(job.remote.MutableTTL) * time.Second
+	if freshness <= 0 {
+		freshness = defaultSyncFreshness
+	}
+	if job.prime {
+		freshness = 0
+	}
+
+	claimed, etag, err := s.store.ClaimGitHubDebSyncLease(ctx, job.remote.Name, s.owner, freshness, syncLeaseDuration)
+	if err != nil {
+		slog.Error("github_deb syncer: claim lease", "remote", job.remote.Name, "error", err)
+		return
+	}
+	if !claimed {
+		return
+	}
+
+	scanCtx, cancel := context.WithTimeout(ctx, s.prov.scanTimeout)
+	defer cancel()
+
+	newEtag, changed, scanErr := s.prov.scanWithState(scanCtx, job.remote, s.store, etag)
+	releaseEtag := etag
+	if scanErr == nil {
+		releaseEtag = newEtag
+	} else {
+		slog.Error("github_deb syncer: scan failed", "remote", job.remote.Name, "error", scanErr)
+	}
+
+	relCtx, relCancel := context.WithTimeout(context.WithoutCancel(ctx), 10*time.Second)
+	defer relCancel()
+	if err := s.store.ReleaseGitHubDebSyncLease(relCtx, job.remote.Name, s.owner, releaseEtag, time.Now()); err != nil {
+		slog.Warn("github_deb syncer: release lease", "remote", job.remote.Name, "error", err)
+	}
+
+	if scanErr == nil && changed {
+		slog.Info("github_deb syncer: refreshed", "remote", job.remote.Name, "prime", job.prime)
+	}
+}
+
+// leaseOwner is a per-replica identity for the lease: hostname plus a random
+// suffix so restarts and colocated replicas never collide.
+func leaseOwner() string {
+	host, _ := os.Hostname()
+	var b [6]byte
+	_, _ = rand.Read(b[:])
+	return host + "-" + hex.EncodeToString(b[:])
+}

internal/provider/deb/syncer_test.go

@@ -0,0 +1,300 @@
+package deb
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"sync"
+	"testing"
+	"time"
+
+	"golang.org/x/time/rate"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/testsupport"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// fakeSyncStore is an in-memory SyncStore: the metadata cache (via the embedded
+// fakeStore) plus the shared sync-state lease, whose claim mirrors the atomic
+// semantics of the real SQL (recency gate AND no live lease).
+type fakeSyncStore struct {
+	*fakeStore
+
+	mu         sync.Mutex
+	remotes    []models.Remote
+	leaseOwner map[string]string
+	leaseExp   map[string]time.Time
+	lastSynced map[string]time.Time
+	etags      map[string]string
+}
+
+func newFakeSyncStore() *fakeSyncStore {
+	return &fakeSyncStore{
+		fakeStore:  newFakeStore(),
+		leaseOwner: map[string]string{},
+		leaseExp:   map[string]time.Time{},
+		lastSynced: map[string]time.Time{},
+		etags:      map[string]string{},
+	}
+}
+
+func (f *fakeSyncStore) ListGitHubDebRemotes(_ context.Context) ([]models.Remote, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return append([]models.Remote(nil), f.remotes...), nil
+}
+
+func (f *fakeSyncStore) ClaimGitHubDebSyncLease(_ context.Context, name, owner string, freshness, lease time.Duration) (bool, string, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	now := time.Now()
+	ls, hasLS := f.lastSynced[name]
+	exp, hasExp := f.leaseExp[name]
+	freshOK := !hasLS || now.Sub(ls) >= freshness
+	leaseOK := !hasExp || exp.Before(now)
+	if freshOK && leaseOK {
+		f.leaseOwner[name] = owner
+		f.leaseExp[name] = now.Add(lease)
+		return true, f.etags[name], nil
+	}
+	return false, "", nil
+}
+
+func (f *fakeSyncStore) ReleaseGitHubDebSyncLease(_ context.Context, name, owner, etag string, syncedAt time.Time) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if f.leaseOwner[name] != owner {
+		return nil
+	}
+	f.lastSynced[name] = syncedAt
+	f.etags[name] = etag
+	delete(f.leaseOwner, name)
+	delete(f.leaseExp, name)
+	return nil
+}
+
+func testSyncConfig() SyncConfig {
+	return SyncConfig{RatePerSec: 1000, Burst: 100, Workers: 1, PollInterval: time.Hour}
+}
+
+// (a) A 304 conditional response must derive nothing: no asset fetches and
+// changed=false, so an unchanged repo is nearly free.
+func TestSyncerConditionalNotModifiedSkipsDerive(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.etag = `"v1"`
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+
+	etag1, changed, err := p.scanWithState(context.Background(), remote, store, "")
+	if err != nil {
+		t.Fatalf("first scan: %v", err)
+	}
+	if !changed || etag1 != `"v1"` {
+		t.Fatalf("first scan changed=%v etag=%q, want true and \"v1\"", changed, etag1)
+	}
+	priorRange := fx.rangeHit["demo_1.2-3_amd64.deb"]
+	if priorRange == 0 {
+		t.Fatal("first scan should have fetched the asset control")
+	}
+
+	etag2, changed2, err := p.scanWithState(context.Background(), remote, store, etag1)
+	if err != nil {
+		t.Fatalf("second scan: %v", err)
+	}
+	if changed2 {
+		t.Fatal("304 scan must report changed=false")
+	}
+	if etag2 != etag1 {
+		t.Fatalf("etag changed across 304: %q -> %q", etag1, etag2)
+	}
+	if fx.notModHit != 1 {
+		t.Fatalf("want exactly one 304 releases response, got %d", fx.notModHit)
+	}
+	if got := fx.rangeHit["demo_1.2-3_amd64.deb"]; got != priorRange {
+		t.Fatalf("304 scan re-fetched asset control: %d -> %d", priorRange, got)
+	}
+}
+
+// (b) On a real change, only the newly added asset is derived.
+func TestSyncerIncrementalDerivesOnlyNewAsset(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.etag = `"v1"`
+	p := newTestProvider()
+	store := newFakeStore()
+	remote := fx.remote()
+
+	if _, _, err := p.scanWithState(context.Background(), remote, store, ""); err != nil {
+		t.Fatalf("first scan: %v", err)
+	}
+	demoRange := fx.rangeHit["demo_1.2-3_amd64.deb"]
+
+	fx.debBytes["other_9_arm64.deb"] = testsupport.MinimalDeb("other", "9", "arm64")
+	fx.etag = `"v2"`
+
+	if _, changed, err := p.scanWithState(context.Background(), remote, store, `"v1"`); err != nil || !changed {
+		t.Fatalf("second scan changed=%v err=%v", changed, err)
+	}
+
+	rows, _ := store.ListDebMetadataEntries(context.Background(), remote.Name)
+	if len(rows) != 2 {
+		t.Fatalf("want 2 cached rows after incremental derive, got %d", len(rows))
+	}
+	if got := fx.rangeHit["demo_1.2-3_amd64.deb"]; got != demoRange {
+		t.Fatalf("already-cached asset was re-fetched: %d -> %d", demoRange, got)
+	}
+	if fx.rangeHit["other_9_arm64.deb"] == 0 {
+		t.Fatal("newly added asset was not derived")
+	}
+}
+
+// (c) The shared limiter caps the request rate.
+func TestRateLimiterCapsRequestRate(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	p := newTestProvider()
+	p.limiter = rate.NewLimiter(rate.Every(120*time.Millisecond), 1)
+	remote := fx.remote()
+
+	start := time.Now()
+	for i := 0; i < 3; i++ {
+		if _, _, _, err := p.fetchReleases(context.Background(), remote, ""); err != nil {
+			t.Fatalf("fetchReleases %d: %v", i, err)
+		}
+	}
+	if elapsed := time.Since(start); elapsed < 200*time.Millisecond {
+		t.Fatalf("rate limiter did not throttle: 3 calls took %v, want >= 200ms", elapsed)
+	}
+}
+
+// (d) Concurrent enqueues for the same remote coalesce to a single queued job.
+func TestSyncerEnqueueDedup(t *testing.T) {
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	s := newSyncer(store, p, testSyncConfig())
+	remote := models.Remote{Name: "acme-deb", PackageType: models.PackageGitHubDeb, MutableTTL: 3600}
+
+	var wg sync.WaitGroup
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+		go func() { defer wg.Done(); s.enqueue(remote, false) }()
+	}
+	wg.Wait()
+
+	if got := len(s.jobs); got != 1 {
+		t.Fatalf("want exactly 1 coalesced job, got %d", got)
+	}
+}
+
+// (e) Prime-on-create enqueues a prime job.
+func TestSyncerEnqueuePrime(t *testing.T) {
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	s := newSyncer(store, p, testSyncConfig())
+	remote := models.Remote{Name: "acme-deb", PackageType: models.PackageGitHubDeb, MutableTTL: 3600}
+
+	s.EnqueuePrime(remote)
+	select {
+	case job := <-s.jobs:
+		if !job.prime || job.remote.Name != "acme-deb" {
+			t.Fatalf("bad prime job: %+v", job)
+		}
+	default:
+		t.Fatal("EnqueuePrime did not enqueue a job")
+	}
+}
+
+// (f) A held lease prevents a second replica from scanning.
+func TestSyncerLeasePreventsSecondReplica(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.etag = `"v1"`
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	s := newSyncer(store, p, testSyncConfig())
+	remote := fx.remote()
+
+	claimed, _, err := store.ClaimGitHubDebSyncLease(context.Background(), remote.Name, "replica-1", time.Duration(remote.MutableTTL)*time.Second, syncLeaseDuration)
+	if err != nil || !claimed {
+		t.Fatalf("replica-1 claim: claimed=%v err=%v", claimed, err)
+	}
+
+	s.process(context.Background(), syncJob{remote: remote})
+
+	if fx.releasesHit != 0 {
+		t.Fatalf("second replica scanned while lease held: %d releases calls", fx.releasesHit)
+	}
+	if rows, _ := store.ListDebMetadataEntries(context.Background(), remote.Name); len(rows) != 0 {
+		t.Fatalf("second replica derived metadata while lease held: %d rows", len(rows))
+	}
+}
+
+// With the syncer wired and the cache empty, an index request enqueues a prime
+// and returns a retryable 503 when it has not landed within the cold wait.
+func TestServeRemoteColdStartReturns503(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	p.coldWait = 300 * time.Millisecond
+	_ = newSyncer(store, p, testSyncConfig()) // binds p.syncer, but no workers running
+	remote := fx.remote()
+
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-deb/Packages", nil)
+	if !p.ServeRemote(rec, req, remote, "Packages", "https://x", store) {
+		t.Fatal("ServeRemote did not handle Packages")
+	}
+	if rec.Code != http.StatusServiceUnavailable {
+		t.Fatalf("cold empty cache must return 503, got %d", rec.Code)
+	}
+	if rec.Header().Get("Retry-After") == "" {
+		t.Fatal("503 should carry Retry-After")
+	}
+	if got := len(p.syncer.jobs); got != 1 {
+		t.Fatalf("cold start did not enqueue a prime, jobs=%d", got)
+	}
+}
+
+// With the cache warm, the same request serves the index immediately (no 503).
+func TestServeRemoteWarmCacheServesImmediately(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	_ = newSyncer(store, p, testSyncConfig())
+	remote := fx.remote()
+
+	if err := p.scan(context.Background(), remote, store); err != nil {
+		t.Fatalf("warm scan: %v", err)
+	}
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/remote/acme-deb/Packages", nil)
+	if !p.ServeRemote(rec, req, remote, "Packages", "https://x", store) {
+		t.Fatal("ServeRemote did not handle Packages")
+	}
+	if rec.Code != http.StatusOK {
+		t.Fatalf("warm cache must serve 200, got %d body=%s", rec.Code, rec.Body.String())
+	}
+}
+
+// A prime job (freshness 0) runs even right after a sync; a periodic job at the
+// same moment is gated by the recency window.
+func TestSyncerPrimeBypassesRecencyPeriodicDoesNot(t *testing.T) {
+	fx := newGitHubFixture(t, true)
+	fx.etag = `"v1"`
+	store := newFakeSyncStore()
+	p := newTestProvider()
+	s := newSyncer(store, p, testSyncConfig())
+	remote := fx.remote()
+
+	var _ provider.RemoteMetadataStore = store
+
+	s.process(context.Background(), syncJob{remote: remote, prime: true})
+	if rows, _ := store.ListDebMetadataEntries(context.Background(), remote.Name); len(rows) != 1 {
+		t.Fatalf("prime did not derive: %d rows", len(rows))
+	}
+	releasesAfterPrime := fx.releasesHit
+
+	s.process(context.Background(), syncJob{remote: remote, prime: false})
+	if fx.releasesHit != releasesAfterPrime {
+		t.Fatalf("periodic scan ran inside recency window: %d -> %d releases calls", releasesAfterPrime, fx.releasesHit)
+	}
+}