feat: serve local docker repos as a real registry

Local docker repos previously had no write path — the /v2 Docker Registry
API only proxied to upstreams. This makes a local docker repo a genuine
registry so `docker push`/`docker pull` (and podman/skopeo/buildah) work
against it directly, matching the project principle that a local repo is the
real thing rather than a mirror.

- Implement the Docker Registry HTTP API V2 write/read half for local docker
  repos: blob uploads (monolithic and chunked POST/PATCH/PUT), manifest push,
  tags list, and blob/manifest GET/HEAD.
- Store blobs and manifests through the existing content-addressable store;
  keep a local_files reference per (repo, image) so the GC does not reap them.
  Tags are mutable (UpsertLocalFile); digests and blobs are immutable.
- Dispatch /v2 reads to the local handler for local docker repos and fall
  through to the upstream proxy otherwise; writes are local-docker only.
- Add UpsertLocalFile for mutable tag references.
- Cover the push/pull round-trip with a dockerised e2e test and unit-test the
  registry path parser. Document the registry in the README.

.gitignore

@@ -1,5 +1,5 @@
 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.

README.md

@@ -89,6 +89,54 @@ 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 |

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)
+	}
+}

go.mod

@@ -7,12 +7,14 @@ 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/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
+	golang.org/x/crypto v0.51.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -45,7 +47,6 @@ 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
@@ -96,7 +97,6 @@ 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

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 +1,473 @@
+package v1
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"os"
+	"sort"
+	"strings"
+	"sync"
+
+	"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"
+
+// uploadSession is an in-progress chunked blob upload, buffered to a temp file
+// on disk. Sessions are held in-memory keyed by upload UUID, so a single push's
+// PATCH/PUT chunks must be served by the same replica — true for the
+// homelab single-instance deployment. Monolithic uploads avoid this entirely.
+type uploadSession struct {
+	file *os.File
+	size int64
+}
+
+type uploadStore struct {
+	mu       sync.Mutex
+	sessions map[string]*uploadSession
+}
+
+func newUploadStore() *uploadStore {
+	return &uploadStore{sessions: make(map[string]*uploadSession)}
+}
+
+func (s *uploadStore) create() (string, *uploadSession, error) {
+	f, err := os.CreateTemp("", "docker-upload-*")
+	if err != nil {
+		return "", nil, err
+	}
+	id := uuid.NewString()
+	sess := &uploadSession{file: f}
+	s.mu.Lock()
+	s.sessions[id] = sess
+	s.mu.Unlock()
+	return id, sess, nil
+}
+
+func (s *uploadStore) get(id string) *uploadSession {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	return s.sessions[id]
+}
+
+func (s *uploadStore) remove(id string) {
+	s.mu.Lock()
+	sess := s.sessions[id]
+	delete(s.sessions, id)
+	s.mu.Unlock()
+	if sess != nil {
+		sess.file.Close()
+		os.Remove(sess.file.Name())
+	}
+}
+
+// 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 || (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
+	}
+
+	id, _, err := h.uploads.create()
+	if 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
+	}
+	sess := h.uploads.get(req.ref)
+	if sess == nil {
+		dockerError(w, http.StatusNotFound, "BLOB_UPLOAD_UNKNOWN", "unknown upload")
+		return
+	}
+	n, err := io.Copy(sess.file, r.Body)
+	if err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	sess.size += n
+	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", sess.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
+	}
+	sess := h.uploads.get(req.ref)
+	if sess == nil {
+		dockerError(w, http.StatusNotFound, "BLOB_UPLOAD_UNKNOWN", "unknown upload")
+		return
+	}
+	defer h.uploads.remove(req.ref)
+
+	if _, err := io.Copy(sess.file, r.Body); err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	if _, err := sess.file.Seek(0, io.SeekStart); err != nil {
+		dockerError(w, http.StatusInternalServerError, "UNKNOWN", err.Error())
+		return
+	}
+	h.dockerCommitBlob(w, r, remote, req.image, digest, sess.file)
+}
+
+// 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 +23,20 @@ type ProxyHandler struct {
 	db            *database.DB
 	store         *storage.S3
 	local         *v2.LocalHandler
+	cas           *storage.CAS
+	uploads       *uploadStore
 }
 
 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),
+		uploads:       newUploadStore(),
+	}
 }
 
 func (h *ProxyHandler) Routes() chi.Router {
@@ -37,12 +47,20 @@ 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.handleProxyHead)
+	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
 }
 

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/objects.go

@@ -75,7 +75,7 @@ func (h *ObjectsHandler) evictLocal(w http.ResponseWriter, r *http.Request) {
 	repoName := chi.URLParam(r, "name")
 	path := chi.URLParam(r, "*")
 
-	if err := h.db.DeleteLocalFile(r.Context(), repoName, path); err != nil {
+	if err := deleteLocalFile(r.Context(), h.db, repoName, path); err != nil {
 		http.Error(w, fmt.Sprintf("evict failed: %v", err), http.StatusInternalServerError)
 		return
 	}

internal/config/env.go

@@ -24,6 +24,14 @@ 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
 }
 
 func (c *Config) DatabaseDSN() string {
@@ -59,6 +67,10 @@ 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"),
 	}
 
 	return cfg, nil

internal/database/local_files.go

@@ -38,6 +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

internal/database/postgres.go

@@ -158,6 +158,13 @@ func (db *DB) migrate() error {
 		);
 
 		CREATE INDEX IF NOT EXISTS idx_rpm_metadata_repo ON rpm_metadata(repo_name);
+
+		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/rpm_metadata.go

@@ -32,6 +32,11 @@ func (db *DB) InsertRPMMetadata(ctx context.Context, meta *provider.RPMMetadata)
 	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

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/provider/provider.go

@@ -53,10 +53,20 @@ type PostUploadHook interface {
 	AfterUpload(ctx context.Context, repoName, storagePath, contentHash string, blobs BlobReader, db MetadataStore)
 }
 
+// PostDeleteHook lets a provider clean up derived state (e.g. RPM metadata that
+// feeds generated repodata) after a local file is removed.
+type PostDeleteHook interface {
+	AfterDelete(ctx context.Context, repoName, storagePath string, db MetadataDeleter) error
+}
+
 type MetadataStore interface {
 	InsertRPMMetadata(ctx context.Context, meta *RPMMetadata) error
 }
 
+type MetadataDeleter interface {
+	DeleteRPMMetadata(ctx context.Context, repoName, filePath string) error
+}
+
 type RPMMetadataReader interface {
 	ListRPMMetadataEntries(ctx context.Context, repoName string) ([]RPMMetadata, error)
 }

internal/provider/rpm/rpm.go

@@ -151,6 +151,15 @@ func (p *Provider) AfterUpload(ctx context.Context, repoName, storagePath, conte
 	slog.Info("rpm 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 {
+	if err := db.DeleteRPMMetadata(ctx, repoName, storagePath); err != nil {
+		slog.Error("rpm metadata: delete failed", "repo", repoName, "path", storagePath, "error", err)
+		return err
+	}
+	slog.Info("rpm metadata: deleted", "repo", repoName, "path", storagePath)
+	return nil
+}
+
 func rpmDepFromEntry(e rpmlib.Dependency) provider.RPMDep {
 	dep := provider.RPMDep{Name: e.Name()}
 	if e.Flags() != 0 {

internal/provider/terraform/terraform.go

@@ -26,6 +26,27 @@ var providerZipRe = regexp.MustCompile(
 
 var semverRe = regexp.MustCompile(`^[0-9]+\.[0-9]+\.[0-9]+(?:-[a-zA-Z0-9.]+)?$`)
 
+// ParsedProviderZip describes a terraform-provider-{type}_{version}_{os}_{arch}.zip
+// filename. Ok is false when the name doesn't match that convention.
+type ParsedProviderZip struct {
+	Type    string
+	Version string
+	OS      string
+	Arch    string
+	Ok      bool
+}
+
+// ParseProviderZip extracts the type, version and platform from a provider zip
+// filename (the base name, not a full path). It's the canonical parser shared by
+// the network-mirror index and the provider registry handler.
+func ParseProviderZip(filename string) ParsedProviderZip {
+	m := providerZipRe.FindStringSubmatch(filename)
+	if m == nil {
+		return ParsedProviderZip{}
+	}
+	return ParsedProviderZip{Type: m[1], Version: m[2], OS: m[3], Arch: m[4], Ok: true}
+}
+
 type Provider struct{}
 
 func (p *Provider) Type() models.PackageType { return models.PackageTerraform }

internal/provider/terraform/terraform_extra_test.go

@@ -0,0 +1,171 @@
+package terraform
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+type fakeFileStore struct{ entries []provider.FileEntry }
+
+func (f fakeFileStore) ListFilesByPrefix(_ context.Context, _, prefix string) ([]provider.FileEntry, error) {
+	var out []provider.FileEntry
+	for _, e := range f.entries {
+		if strings.HasPrefix(e.FilePath, prefix) {
+			out = append(out, e)
+		}
+	}
+	return out, nil
+}
+func (f fakeFileStore) ListPackages(_ context.Context, _ string) ([]string, error) { return nil, nil }
+
+func TestTFPureFuncs(t *testing.T) {
+	p := &Provider{}
+	if p.Classify("hashicorp/aws/versions") != provider.Mutable {
+		t.Error("versions should be mutable")
+	}
+	if p.Classify("hashicorp/aws/terraform-provider-aws_1.0.0_linux_amd64.zip") != provider.Immutable {
+		t.Error("zip should be immutable")
+	}
+	if got := p.UpstreamURL(models.Remote{BaseURL: "https://registry.terraform.io"}, "hashicorp/aws/versions"); got != "https://registry.terraform.io/v1/providers/hashicorp/aws/versions" {
+		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")
+	}
+	_ = p.ContentType("x.json")
+}
+
+func TestTFValidateUpload(t *testing.T) {
+	p := &Provider{}
+	sp, ct, err := p.ValidateUpload("hashicorp/aws/terraform-provider-aws_1.2.3_linux_amd64.zip")
+	if err != nil || sp != "hashicorp/aws/terraform-provider-aws_1.2.3_linux_amd64.zip" || ct != "application/zip" {
+		t.Errorf("valid: sp=%q ct=%q err=%v", sp, ct, err)
+	}
+	if _, _, err := p.ValidateUpload("too/few"); err == nil {
+		t.Error("expected error for wrong path depth")
+	}
+	if _, _, err := p.ValidateUpload("ns/aws/not-a-provider.zip"); err == nil {
+		t.Error("expected error for bad filename")
+	}
+	if _, _, err := p.ValidateUpload("ns/gcp/terraform-provider-aws_1.0.0_linux_amd64.zip"); err == nil {
+		t.Error("expected error for type mismatch")
+	}
+}
+
+func TestTFUploadResponse(t *testing.T) {
+	p := &Provider{}
+	resp := p.UploadResponse("hashicorp/aws/terraform-provider-aws_1.2.3_linux_amd64.zip", "sha256:abc", 100)
+	if resp["namespace"] != "hashicorp" || resp["type"] != "aws" || resp["version"] != "1.2.3" || resp["os"] != "linux" || resp["arch"] != "amd64" {
+		t.Errorf("structured response wrong: %v", resp)
+	}
+	fallback := p.UploadResponse("weird/path", "sha256:x", 1)
+	if fallback["path"] != "weird/path" {
+		t.Errorf("fallback response wrong: %v", fallback)
+	}
+}
+
+func TestTFRewriteResponse(t *testing.T) {
+	p := &Provider{}
+	remote := models.Remote{Name: "tf", ReleasesRemote: "hashicorp-releases"}
+
+	if out, _ := p.RewriteResponse([]byte(`{"download_url":"x"}`), models.Remote{}, "http://proxy"); out != nil {
+		t.Error("no ReleasesRemote should be a no-op")
+	}
+	if out, _ := p.RewriteResponse([]byte("not json"), remote, "http://proxy"); out != nil {
+		t.Error("invalid json should be a no-op")
+	}
+	body := []byte(`{"download_url":"https://releases.hashicorp.com/terraform-provider-aws/1.0/aws.zip"}`)
+	out, err := p.RewriteResponse(body, remote, "http://proxy")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(string(out), "http://proxy/api/v1/remote/hashicorp-releases/") {
+		t.Errorf("download_url not rewritten: %s", out)
+	}
+}
+
+func TestTFServeLocalIndex(t *testing.T) {
+	p := &Provider{}
+	fs := fakeFileStore{entries: []provider.FileEntry{
+		{FilePath: "hashicorp/aws/terraform-provider-aws_1.0.0_linux_amd64.zip", ContentHash: "sha256:deadbeef"},
+		{FilePath: "hashicorp/aws/terraform-provider-aws_1.0.0_darwin_arm64.zip", ContentHash: "sha256:cafe"},
+	}}
+
+	serve := func(path string) *httptest.ResponseRecorder {
+		w := httptest.NewRecorder()
+		r := httptest.NewRequest(http.MethodGet, "/"+path, nil)
+		p.ServeLocalIndex(w, r, fs, "repo", path)
+		return w
+	}
+
+	if w := serve("hashicorp/aws/index.json"); w.Code != 200 || !strings.Contains(w.Body.String(), "1.0.0") {
+		t.Errorf("index.json: code=%d body=%s", w.Code, w.Body.String())
+	}
+	if w := serve("hashicorp/aws/1.0.0.json"); w.Code != 200 || !strings.Contains(w.Body.String(), "linux_amd64") {
+		t.Errorf("version doc: code=%d body=%s", w.Code, w.Body.String())
+	}
+
+	// Not a terraform index path.
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest(http.MethodGet, "/x", nil)
+	if p.ServeLocalIndex(w, r, fs, "repo", "hashicorp/aws/other.txt") {
+		t.Error("non-index path should return false")
+	}
+	if p.ServeLocalIndex(httptest.NewRecorder(), r, fs, "repo", "too/short") {
+		t.Error("short path should return false")
+	}
+}
+
+func TestTFContentTypeAndEmptyIndex(t *testing.T) {
+	p := &Provider{}
+	for path, want := range map[string]string{
+		"x.zip":      "application/zip",
+		"x.sig":      "application/octet-stream",
+		"index.json": "application/json",
+	} {
+		if got := p.ContentType(path); got != want {
+			t.Errorf("ContentType(%q)=%q want %q", path, got, want)
+		}
+	}
+	// index / version doc with no matching files -> 404.
+	empty := fakeFileStore{}
+	w := httptest.NewRecorder()
+	r := httptest.NewRequest(http.MethodGet, "/hashicorp/aws/index.json", nil)
+	p.ServeLocalIndex(w, r, empty, "repo", "hashicorp/aws/index.json")
+	if w.Code != http.StatusNotFound {
+		t.Errorf("empty index should be 404, got %d", w.Code)
+	}
+	w = httptest.NewRecorder()
+	p.ServeLocalIndex(w, r, empty, "repo", "hashicorp/aws/1.0.0.json")
+	if w.Code != http.StatusNotFound {
+		t.Errorf("empty version doc should be 404, got %d", w.Code)
+	}
+}
+
+func TestRewriteDownloadURL(t *testing.T) {
+	// Empty proxy base -> unchanged.
+	if got := rewriteDownloadURL("https://x/a.zip", "rel", ""); got != "https://x/a.zip" {
+		t.Errorf("empty base: %q", got)
+	}
+	// Unparseable URL -> unchanged.
+	if got := rewriteDownloadURL("://bad", "rel", "http://p"); got != "://bad" {
+		t.Errorf("bad url: %q", got)
+	}
+	// Normal rewrite.
+	if got := rewriteDownloadURL("https://cdn/path/a.zip", "rel", "http://p"); got != "http://p/api/v1/remote/rel/path/a.zip" {
+		t.Errorf("rewrite: %q", got)
+	}
+}
+
+func TestTFGenerateLocalIndexUnsupported(t *testing.T) {
+	if _, err := (&Provider{}).GenerateLocalIndex(context.Background(), fakeFileStore{}, "r", "x"); err == nil {
+		t.Error("expected unsupported error")
+	}
+}

internal/server/server.go

@@ -12,6 +12,7 @@ import (
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
 
+	tfregistry "git.unkin.net/unkin/artifactapi/internal/api/terraform"
 	v1 "git.unkin.net/unkin/artifactapi/internal/api/v1"
 	v2 "git.unkin.net/unkin/artifactapi/internal/api/v2"
 	"git.unkin.net/unkin/artifactapi/internal/cache"
@@ -30,6 +31,7 @@ import (
 	_ "git.unkin.net/unkin/artifactapi/internal/provider/terraform"
 	"git.unkin.net/unkin/artifactapi/internal/proxy"
 	"git.unkin.net/unkin/artifactapi/internal/storage"
+	"git.unkin.net/unkin/artifactapi/internal/tfsign"
 	"git.unkin.net/unkin/artifactapi/internal/virtual"
 )
 
@@ -43,6 +45,7 @@ type Server struct {
 	engine       *proxy.Engine
 	virtEngine   *virtual.Engine
 	localHandler *v2.LocalHandler
+	tfRegistry   *tfregistry.Handler
 	gc           *gc.Collector
 }
 
@@ -67,6 +70,25 @@ func New(cfg *config.Config, version string) (*Server, error) {
 	virtEngine := virtual.NewEngine(db, engine)
 	collector := gc.New(db, s3, 1*time.Hour)
 
+	// The terraform registry signs with a GPG key. A configured file wins (BYO
+	// key); otherwise artifactapi generates one on first start and persists it in
+	// the database so every replica shares it. A failure here must not take the
+	// server down — the registry just stays disabled.
+	var signer *tfsign.Signer
+	if cfg.TFSigningKeyPath != "" {
+		signer, err = tfsign.Load(cfg.TFSigningKeyPath, cfg.TFSigningKeyPassphrase)
+	} else {
+		signer, err = tfsign.LoadOrCreate(context.Background(), db, "terraform-provider")
+	}
+	if err != nil {
+		slog.Warn("terraform provider registry disabled", "error", err)
+		signer = nil
+	}
+	tfRegistry := tfregistry.NewHandler(db, signer, cfg.TFProviderProtocols)
+	if tfRegistry.Enabled() {
+		slog.Info("terraform provider registry enabled", "key_id", signer.KeyID())
+	}
+
 	s := &Server{
 		cfg:          cfg,
 		version:      version,
@@ -76,6 +98,7 @@ func New(cfg *config.Config, version string) (*Server, error) {
 		engine:       engine,
 		virtEngine:   virtEngine,
 		localHandler: localHandler,
+		tfRegistry:   tfRegistry,
 		gc:           collector,
 	}
 
@@ -95,6 +118,12 @@ func (s *Server) routes() chi.Router {
 
 	r.Get("/health", s.handleHealth)
 	r.Get("/", s.handleRoot)
+	r.Get("/version", s.handleVersion)
+
+	// Terraform provider registry: service discovery at the well-known path,
+	// providers.v1 protocol under /terraform/v1/providers.
+	r.Get("/.well-known/terraform.json", s.tfRegistry.ServiceDiscovery)
+	r.Mount(tfregistry.MountPath, s.tfRegistry.Routes())
 
 	proxyHandler := v1.NewProxyHandler(s.engine, s.virtEngine, s.db, s.store, s.localHandler)
 	r.Mount("/api/v1", proxyHandler.Routes())
@@ -143,7 +172,13 @@ func (s *Server) handleHealth(w http.ResponseWriter, r *http.Request) {
 	fmt.Fprint(w, `{"status":"ok"}`)
 }
 
+// handleRoot sends browsers landing on the bare domain to the web UI, which is
+// served under /ui. The service identity that used to live here is at /version.
 func (s *Server) handleRoot(w http.ResponseWriter, r *http.Request) {
+	http.Redirect(w, r, "/ui/", http.StatusFound)
+}
+
+func (s *Server) handleVersion(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusOK)
 	fmt.Fprintf(w, `{"name":"artifactapi","version":"%s"}`, s.version)

internal/server/server_test.go

@@ -129,13 +129,32 @@ func req(t *testing.T, method, path string, body string) (*http.Response, []byte
 	return resp, b
 }
 
+// reqNoRedirect issues a request without following redirects so the response's
+// status and Location header can be asserted directly.
+func reqNoRedirect(t *testing.T, method, path string) *http.Response {
+	t.Helper()
+	rq, _ := http.NewRequest(method, testTS.URL+path, nil)
+	client := &http.Client{CheckRedirect: func(*http.Request, []*http.Request) error {
+		return http.ErrUseLastResponse
+	}}
+	resp, err := client.Do(rq)
+	if err != nil {
+		t.Fatalf("%s %s: %v", method, path, err)
+	}
+	resp.Body.Close()
+	return resp
+}
+
 func TestServerHealthAndRoot(t *testing.T) {
 	requireStack(t)
 	if resp, _ := req(t, "GET", "/health", ""); resp.StatusCode != 200 {
 		t.Errorf("health: %d", resp.StatusCode)
 	}
-	if resp, b := req(t, "GET", "/", ""); resp.StatusCode != 200 || !strings.Contains(string(b), "test-version") {
-		t.Errorf("root: %d %s", resp.StatusCode, b)
+	if resp := reqNoRedirect(t, "GET", "/"); resp.StatusCode != http.StatusFound || resp.Header.Get("Location") != "/ui/" {
+		t.Errorf("root redirect: %d %q", resp.StatusCode, resp.Header.Get("Location"))
+	}
+	if resp, b := req(t, "GET", "/version", ""); resp.StatusCode != 200 || !strings.Contains(string(b), "test-version") {
+		t.Errorf("version: %d %s", resp.StatusCode, b)
 	}
 	if resp, _ := req(t, "GET", "/api/v2/health", ""); resp.StatusCode != 200 {
 		t.Errorf("health v2: %d", resp.StatusCode)

internal/tfsign/signer.go

@@ -0,0 +1,173 @@
+// Package tfsign loads a GPG signing key and produces the detached signatures
+// the Terraform provider registry protocol requires over SHA256SUMS files.
+package tfsign
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"os"
+	"strings"
+
+	"golang.org/x/crypto/openpgp"
+	"golang.org/x/crypto/openpgp/armor"
+)
+
+// KeyStore persists a generated signing key. *database.DB satisfies it.
+type KeyStore interface {
+	GetSigningKey(ctx context.Context, purpose string) (armor, keyID string, found bool, err error)
+	InsertSigningKeyIfAbsent(ctx context.Context, purpose, armor, keyID string) error
+}
+
+// LoadOrCreate returns a signer for purpose, generating and persisting a new key
+// the first time it is needed. It is safe across replicas: a lost insert race
+// just re-reads whichever key won.
+func LoadOrCreate(ctx context.Context, store KeyStore, purpose string) (*Signer, error) {
+	armored, _, found, err := store.GetSigningKey(ctx, purpose)
+	if err != nil {
+		return nil, err
+	}
+	if !found {
+		newArmor, keyID, err := Generate()
+		if err != nil {
+			return nil, err
+		}
+		if err := store.InsertSigningKeyIfAbsent(ctx, purpose, newArmor, keyID); err != nil {
+			return nil, err
+		}
+		if armored, _, _, err = store.GetSigningKey(ctx, purpose); err != nil {
+			return nil, err
+		}
+	}
+	return LoadArmored(armored, "")
+}
+
+// Signer holds a decrypted GPG entity and exposes what the registry download
+// response needs: a detached signature, the armored public key, and the key ID.
+type Signer struct {
+	entity      *openpgp.Entity
+	publicASCII string
+	keyID       string
+}
+
+// Load reads an armored private key from path, decrypting it with passphrase if
+// the key is protected. A blank path returns (nil, nil): a nil *Signer means the
+// caller should fall back to another source (e.g. a DB-stored key).
+func Load(path, passphrase string) (*Signer, error) {
+	if path == "" {
+		return nil, nil
+	}
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("open signing key: %w", err)
+	}
+	return fromArmor(string(data), passphrase, path)
+}
+
+// LoadArmored builds a signer from an in-memory armored private key, e.g. one
+// read from the database. A blank key returns (nil, nil).
+func LoadArmored(armored, passphrase string) (*Signer, error) {
+	if armored == "" {
+		return nil, nil
+	}
+	return fromArmor(armored, passphrase, "stored key")
+}
+
+// Generate creates a fresh signing keypair and returns the armored private key
+// (to persist) and its uppercase key id.
+func Generate() (armoredPrivateKey, keyID string, err error) {
+	entity, err := openpgp.NewEntity("artifactapi terraform registry", "provider signing", "artifactapi@localhost", nil)
+	if err != nil {
+		return "", "", err
+	}
+	var buf bytes.Buffer
+	w, err := armor.Encode(&buf, openpgp.PrivateKeyType, nil)
+	if err != nil {
+		return "", "", err
+	}
+	if err := entity.SerializePrivate(w, nil); err != nil {
+		return "", "", err
+	}
+	if err := w.Close(); err != nil {
+		return "", "", err
+	}
+	return buf.String(), strings.ToUpper(entity.PrimaryKey.KeyIdString()), nil
+}
+
+func fromArmor(armored, passphrase, src string) (*Signer, error) {
+	keyring, err := openpgp.ReadArmoredKeyRing(strings.NewReader(armored))
+	if err != nil {
+		return nil, fmt.Errorf("read signing key: %w", err)
+	}
+	if len(keyring) == 0 {
+		return nil, fmt.Errorf("signing key (%s) contains no entities", src)
+	}
+	entity := keyring[0]
+
+	if entity.PrivateKey == nil {
+		return nil, fmt.Errorf("signing key (%s) has no private key material", src)
+	}
+	if entity.PrivateKey.Encrypted {
+		if err := decrypt(entity, passphrase); err != nil {
+			return nil, err
+		}
+	}
+
+	pub, err := armorPublicKey(entity)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Signer{
+		entity:      entity,
+		publicASCII: pub,
+		keyID:       entity.PrimaryKey.KeyIdString(),
+	}, nil
+}
+
+// decrypt unlocks the entity's private key and all subkeys with the passphrase.
+func decrypt(entity *openpgp.Entity, passphrase string) error {
+	pw := []byte(passphrase)
+	if err := entity.PrivateKey.Decrypt(pw); err != nil {
+		return fmt.Errorf("decrypt signing key: %w", err)
+	}
+	for _, sub := range entity.Subkeys {
+		if sub.PrivateKey != nil && sub.PrivateKey.Encrypted {
+			_ = sub.PrivateKey.Decrypt(pw)
+		}
+	}
+	return nil
+}
+
+func armorPublicKey(entity *openpgp.Entity) (string, error) {
+	var buf bytes.Buffer
+	w, err := armor.Encode(&buf, openpgp.PublicKeyType, nil)
+	if err != nil {
+		return "", err
+	}
+	if err := entity.Serialize(w); err != nil {
+		return "", err
+	}
+	if err := w.Close(); err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}
+
+// Sign returns a binary detached signature over message, matching the
+// SHA256SUMS.sig format Terraform verifies.
+func (s *Signer) Sign(message []byte) ([]byte, error) {
+	var buf bytes.Buffer
+	if err := openpgp.DetachSign(&buf, s.entity, bytes.NewReader(message), nil); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+// PublicKeyArmor returns the ASCII-armored public key for the registry's
+// signing_keys response.
+func (s *Signer) PublicKeyArmor() string { return s.publicASCII }
+
+// KeyID returns the 16-hex-char uppercase key ID Terraform matches against the
+// signature's issuer.
+func (s *Signer) KeyID() string { return strings.ToUpper(s.keyID) }

internal/tfsign/signer_test.go

@@ -0,0 +1,155 @@
+package tfsign
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"path/filepath"
+	"regexp"
+	"testing"
+
+	"golang.org/x/crypto/openpgp"
+	"golang.org/x/crypto/openpgp/armor"
+)
+
+// armoredPrivateKey generates a throwaway armored private key for tests.
+func armoredPrivateKey(t *testing.T) string {
+	t.Helper()
+	e, err := openpgp.NewEntity("artifactapi test", "tf registry", "tf@example.com", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var buf bytes.Buffer
+	w, err := armor.Encode(&buf, openpgp.PrivateKeyType, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := e.SerializePrivate(w, nil); err != nil {
+		t.Fatal(err)
+	}
+	w.Close()
+	return buf.String()
+}
+
+func writeKey(t *testing.T, contents string) string {
+	t.Helper()
+	p := filepath.Join(t.TempDir(), "private-key.asc")
+	if err := os.WriteFile(p, []byte(contents), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	return p
+}
+
+func TestLoadSignAndVerify(t *testing.T) {
+	path := writeKey(t, armoredPrivateKey(t))
+	s, err := Load(path, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if s == nil {
+		t.Fatal("expected a signer")
+	}
+
+	if !regexp.MustCompile(`^[0-9A-F]{16}$`).MatchString(s.KeyID()) {
+		t.Errorf("key id %q is not 16 uppercase hex chars", s.KeyID())
+	}
+
+	msg := []byte("deadbeef  terraform-provider-x_1.0.0_linux_amd64.zip\n")
+	sig, err := s.Sign(msg)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// The advertised public key must verify the signature over the same bytes.
+	keyring, err := openpgp.ReadArmoredKeyRing(bytes.NewReader([]byte(s.PublicKeyArmor())))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := openpgp.CheckDetachedSignature(keyring, bytes.NewReader(msg), bytes.NewReader(sig)); err != nil {
+		t.Errorf("signature did not verify: %v", err)
+	}
+}
+
+func TestGenerateAndLoadArmored(t *testing.T) {
+	priv, keyID, err := Generate()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !regexp.MustCompile(`^[0-9A-F]{16}$`).MatchString(keyID) {
+		t.Errorf("generated key id %q malformed", keyID)
+	}
+
+	s, err := LoadArmored(priv, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if s.KeyID() != keyID {
+		t.Errorf("loaded key id %q != generated %q", s.KeyID(), keyID)
+	}
+
+	msg := []byte("abc  terraform-provider-x_1.0.0_linux_amd64.zip\n")
+	sig, err := s.Sign(msg)
+	if err != nil {
+		t.Fatal(err)
+	}
+	keyring, _ := openpgp.ReadArmoredKeyRing(bytes.NewReader([]byte(s.PublicKeyArmor())))
+	if _, err := openpgp.CheckDetachedSignature(keyring, bytes.NewReader(msg), bytes.NewReader(sig)); err != nil {
+		t.Errorf("signature did not verify: %v", err)
+	}
+}
+
+// memStore is an in-memory KeyStore that records how many keys it accepted.
+type memStore struct {
+	armor, keyID string
+	found        bool
+	inserts      int
+}
+
+func (m *memStore) GetSigningKey(_ context.Context, _ string) (string, string, bool, error) {
+	return m.armor, m.keyID, m.found, nil
+}
+
+func (m *memStore) InsertSigningKeyIfAbsent(_ context.Context, _, armor, keyID string) error {
+	if !m.found { // ON CONFLICT DO NOTHING
+		m.armor, m.keyID, m.found = armor, keyID, true
+		m.inserts++
+	}
+	return nil
+}
+
+func TestLoadOrCreateGeneratesOnceThenReuses(t *testing.T) {
+	store := &memStore{}
+
+	first, err := LoadOrCreate(context.Background(), store, "terraform-provider")
+	if err != nil || first == nil {
+		t.Fatalf("first LoadOrCreate: signer=%v err=%v", first, err)
+	}
+
+	second, err := LoadOrCreate(context.Background(), store, "terraform-provider")
+	if err != nil || second == nil {
+		t.Fatalf("second LoadOrCreate: signer=%v err=%v", second, err)
+	}
+
+	if store.inserts != 1 {
+		t.Errorf("expected exactly one key generated, got %d", store.inserts)
+	}
+	if first.KeyID() != second.KeyID() {
+		t.Errorf("key id changed between loads: %q vs %q", first.KeyID(), second.KeyID())
+	}
+}
+
+func TestLoadEmptyPathDisabled(t *testing.T) {
+	s, err := Load("", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if s != nil {
+		t.Error("empty path should yield a nil (disabled) signer")
+	}
+}
+
+func TestLoadMissingFile(t *testing.T) {
+	if _, err := Load(filepath.Join(t.TempDir(), "nope.asc"), ""); err == nil {
+		t.Error("expected an error for a missing key file")
+	}
+}