Add helm local repositories (#140)

In-house charts have nowhere to publish: a helm local stores uploads but serves no index.yaml, and the helm virtual merger drops every chart field except name/version/urls.

- add helm local uploads (`PUT .../files/<name>-<version>.tgz`) recording each Chart.yaml in a new `helm_metadata` table; mismatched filenames stay out of the index
- bound chart parsing (50MiB decompressed, 10k entries, 1MiB Chart.yaml)
- generate a deterministic `index.yaml` with sha256 digests and path-escaped relative urls
- keep all chart fields when merging helm virtual indexes, expanding YAML aliases
- add a real-helm e2e-docker test, UI snippet and README section

Reviewed-on: #140
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

README.md

@@ -1,6 +1,6 @@
 # ArtifactAPI
 
-Caching proxy for package repositories. Single Go binary, 11 package types, content-addressable storage, managed by Terraform.
+Caching proxy for package repositories. Single Go binary, 12 package types, content-addressable storage, managed by Terraform.
 
 ## Quick Start
 
@@ -33,6 +33,7 @@ API: `http://localhost:8000` | Frontend: `http://localhost:5173`
 | `terraform` | `*/versions` | `*/download/*/*` |
 | `goproxy` | `@v/list`, `@latest` | `.info`, `.mod`, `.zip` |
 | `cargo` | sparse index files (`config.json` synthesized) | `crates/*/*.crate` |
+| `nuget` | `index.json` (service index), registration and flat container indexes | `.nupkg`, `.nuspec` |
 | `github_rpm` | `repodata/*` (synthesized) | `.rpm` (redirected) |
 
 Providers classify paths automatically. Users only configure what to proxy and TTLs.
@@ -261,6 +262,37 @@ there's nothing to provision. To bring your own key instead, point
 `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 helm repository
+
+A local `helm` repo is a real chart repository: `PUT` a packaged chart to
+`/api/v2/remotes/<repo>/files/<chart>-<version>.tgz` and `index.yaml` is
+generated from each chart's `Chart.yaml` (with sha256 digests) at
+`/api/v1/local/<repo>/index.yaml`; a file not named after its `Chart.yaml`
+name and version is stored but left out of the index. Add the local as a
+member of a helm virtual to serve it alongside remotes.
+
+```bash
+helm package ./mychart
+curl -fsSL --upload-file mychart-0.1.0.tgz \
+  https://artifactapi.k8s.syd1.au.unkin.net/api/v2/remotes/<repo>/files/mychart-0.1.0.tgz
+helm repo add <repo> https://artifactapi.k8s.syd1.au.unkin.net/api/v1/local/<repo>
+```
+
+### Local puppet forge
+
+A local `puppet` repo is a Forge: `PUT` a module tarball to
+`/api/v2/remotes/<repo>/files/<owner>-<module>-<version>.tar.gz` and the Forge
+v3 API (`/v3/modules`, `/v3/releases`, `/v3/files`) is served from each
+release's `metadata.json` at `/api/v1/local/<repo>`. Versions are immutable.
+
+```bash
+puppet module build ./hello
+curl -fsSL --upload-file pkg/unkin-hello-0.1.0.tar.gz \
+  https://artifactapi.k8s.syd1.au.unkin.net/api/v2/remotes/<repo>/files/unkin-hello-0.1.0.tar.gz
+puppet module install unkin-hello \
+  --module_repository https://artifactapi.k8s.syd1.au.unkin.net/api/v1/local/<repo>
+```
+
 ### Local docker registry
 
 A local `docker` repo is a real container registry, not a mirror: it serves the

e2e-docker/README.md

@@ -23,10 +23,11 @@ already-running stack.
 
 - **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, cargo) proxied through the
+  helm, pypi, npm, rpm, alpine, puppet, terraform, goproxy, cargo, nuget) 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/`
+- **Local uploads** — puppet (Forge v3 API via real `r10k` and `puppet module install`),
+  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.

e2e-docker/caching_test.go

@@ -30,6 +30,7 @@ func TestCachingPerProvider(t *testing.T) {
 		{"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"},
 		{"cargo", "crates/mycrate/mycrate-1.0.0.crate", "crates/mycrate/mycrate-1.0.0.crate"},
+		{"nuget", "nuget/e2epkg/1.0.0/e2epkg.1.0.0.nupkg", "nuget/e2epkg/1.0.0/e2epkg.1.0.0.nupkg"},
 		{"terraform", "hashicorp/aws/download/pkg.zip", "v1/providers/hashicorp/aws/download/pkg.zip"},
 		{"docker", "library/testimg/blobs/blobdata", "v2/library/testimg/blobs/blobdata"},
 	}

e2e-docker/helm_local_test.go

@@ -0,0 +1,71 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"net/http"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+	"time"
+)
+
+// TestLocalHelmRealClient packages a chart with the real helm CLI, publishes it
+// to a helm local, then drives helm repo add/search/pull/template against the
+// local and against a helm virtual that has the local as a member.
+func TestLocalHelmRealClient(t *testing.T) {
+	network := os.Getenv("COMPOSE_NETWORK")
+	internal := strings.TrimRight(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")
+	}
+
+	createRepo(t, `{"name":"local-helm","package_type":"helm","repo_type":"local"}`)
+	defer deleteRepo(t, "local-helm")
+	createVirtual(t, `{"name":"vhelm","package_type":"helm","members":["local-helm"]}`)
+	defer deleteVirtual(t, "vhelm")
+
+	helm := func(script string) string {
+		t.Helper()
+		out, err := exec.Command("docker", "run", "--rm", "--network", network, "--entrypoint", "sh",
+			"alpine/helm:3.16.4", "-c", "set -eu; "+script).Output()
+		if err != nil {
+			stderr := ""
+			if ee, ok := err.(*exec.ExitError); ok {
+				stderr = string(ee.Stderr)
+			}
+			t.Fatalf("helm script failed: %v\n%s%s", err, out, stderr)
+		}
+		return string(out)
+	}
+
+	chart := helm("cd /tmp && helm create e2echart >/dev/null && helm package e2echart >/dev/null && cat e2echart-0.1.0.tgz")
+	uploadFile(t, "local-helm", "e2echart-0.1.0.tgz", []byte(chart), "application/gzip")
+
+	// Chart metadata is recorded asynchronously after upload; poll the index.
+	var body []byte
+	for deadline := time.Now().Add(15 * time.Second); time.Now().Before(deadline); time.Sleep(500 * time.Millisecond) {
+		var resp *http.Response
+		resp, body = doRequest(t, http.MethodGet, api("/api/v1/local/local-helm/index.yaml"), nil, "")
+		if resp.StatusCode == http.StatusOK && strings.Contains(string(body), "e2echart-0.1.0.tgz") {
+			break
+		}
+	}
+	if !strings.Contains(string(body), "e2echart-0.1.0.tgz") || !strings.Contains(string(body), "digest: ") {
+		t.Fatalf("index.yaml never listed the chart:\n%s", body)
+	}
+
+	for _, repoURL := range []string{internal + "/api/v1/local/local-helm", internal + "/api/v1/virtual/vhelm"} {
+		out := helm("helm repo add e2e " + repoURL + " >/dev/null && " +
+			"helm search repo e2e/e2echart && " +
+			"cd /tmp && helm pull e2e/e2echart --version 0.1.0 && " +
+			"helm template rel e2echart-0.1.0.tgz | grep -c 'kind: Deployment'")
+		if !strings.Contains(out, "e2e/e2echart") || !strings.Contains(out, "0.1.0") || !strings.HasSuffix(strings.TrimSpace(out), "1") {
+			t.Fatalf("helm via %s:\n%s", repoURL, out)
+		}
+	}
+}

e2e-docker/puppet_local_test.go

@@ -0,0 +1,88 @@
+//go:build dockere2e
+
+package e2edocker
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"net/http"
+	"os"
+	"os/exec"
+	"strings"
+	"testing"
+	"time"
+)
+
+const puppetHelloMetadata = `{"name":"unkin-hello","version":"0.1.0","author":"unkin","summary":"e2e","license":"Apache-2.0","source":"https://example.invalid","dependencies":[{"name":"puppetlabs/stdlib","version_requirement":">= 4.0.0 < 10.0.0"}]}`
+
+func puppetModuleTarball(t *testing.T) []byte {
+	t.Helper()
+	var buf bytes.Buffer
+	zw := gzip.NewWriter(&buf)
+	tw := tar.NewWriter(zw)
+	for name, body := range map[string]string{
+		"unkin-hello-0.1.0/metadata.json":     puppetHelloMetadata,
+		"unkin-hello-0.1.0/manifests/init.pp": "class hello {}\n",
+	} {
+		if err := tw.WriteHeader(&tar.Header{Name: name, Mode: 0o644, Size: int64(len(body)), ModTime: time.Now()}); err != nil {
+			t.Fatal(err)
+		}
+		_, _ = tw.Write([]byte(body))
+	}
+	_ = tw.Close()
+	_ = zw.Close()
+	return buf.Bytes()
+}
+
+// TestLocalPuppetRealClient publishes a module to a puppet local and installs
+// it with the real r10k and puppet module tool. The stdlib dependency is not on
+// a local-only forge, so puppet runs with --ignore-dependencies.
+func TestLocalPuppetRealClient(t *testing.T) {
+	network := os.Getenv("COMPOSE_NETWORK")
+	internal := strings.TrimRight(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")
+	}
+
+	createRepo(t, `{"name":"local-puppet","package_type":"puppet","repo_type":"local"}`)
+	defer deleteRepo(t, "local-puppet")
+
+	upload := api("/api/v2/remotes/local-puppet/files/unkin-hello-0.1.0.tar.gz")
+	defer doRequest(t, http.MethodDelete, api("/api/v2/remotes/local-puppet/files/v3/files/unkin-hello-0.1.0.tar.gz"), nil, "")
+	tarball := puppetModuleTarball(t)
+	if resp, body := doRequest(t, http.MethodPut, upload, tarball, "application/gzip"); resp.StatusCode != http.StatusCreated {
+		t.Fatalf("upload: %d %s", resp.StatusCode, body)
+	}
+	if resp, _ := doRequest(t, http.MethodPut, upload, tarball, "application/gzip"); resp.StatusCode != http.StatusConflict {
+		t.Fatalf("re-upload of an existing version: %d, want 409", resp.StatusCode)
+	}
+	if resp, body := getEventually(t, api("/api/v1/local/local-puppet/v3/releases/unkin-hello-0.1.0"), 15*time.Second); resp.StatusCode != http.StatusOK || !strings.Contains(string(body), `"file_md5"`) {
+		t.Fatalf("release never indexed: %d %s", resp.StatusCode, body)
+	}
+
+	forge := internal + "/api/v1/local/local-puppet"
+	run := func(image, script string) string {
+		t.Helper()
+		out, err := exec.Command("docker", "run", "--rm", "--network", network, "--entrypoint", "sh", image, "-c", "set -eu; "+script).CombinedOutput()
+		if err != nil {
+			t.Fatalf("%s failed: %v\n%s", image, err, out)
+		}
+		return string(out)
+	}
+
+	out := run("ghcr.io/voxpupuli/r10k:latest", "cd /tmp && printf 'forge:\\n  baseurl: "+forge+"\\n' > r10k.yaml && "+
+		"printf \"forge '"+forge+"'\\nmod 'unkin-hello', '0.1.0'\\n\" > Puppetfile && "+
+		"r10k puppetfile install -c r10k.yaml --verbose && cat modules/hello/metadata.json")
+	if !strings.Contains(out, `"unkin-hello"`) {
+		t.Fatalf("r10k did not install unkin-hello:\n%s", out)
+	}
+
+	out = run("ghcr.io/openvoxproject/openvoxagent:latest", "export PATH=/opt/puppetlabs/bin:$PATH; puppet module install unkin-hello --module_repository "+forge+" --ignore-dependencies --target-dir /tmp/mods && puppet module list --color=false --modulepath /tmp/mods")
+	if !strings.Contains(out, "unkin-hello (v0.1.0)") {
+		t.Fatalf("puppet module install did not install unkin-hello:\n%s", out)
+	}
+}

internal/api/v1/proxy.go

@@ -1,6 +1,7 @@
 package v1
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -105,13 +106,24 @@ func (h *ProxyHandler) handleProxy(w http.ResponseWriter, r *http.Request) {
 	}
 	defer result.Reader.Close()
 
+	var body io.Reader = result.Reader
+	if sr, ok := prov.(provider.ServeRewriter); ok && prov.Classify(path) == provider.Mutable {
+		raw, err := io.ReadAll(result.Reader)
+		if err != nil {
+			http.Error(w, "bad gateway", http.StatusBadGateway)
+			return
+		}
+		raw = sr.RewriteServed(raw, *remote, fmt.Sprintf("%s://%s", scheme(r), r.Host))
+		body, result.Size = bytes.NewReader(raw), int64(len(raw))
+	}
+
 	w.Header().Set("Content-Type", result.ContentType)
 	w.Header().Set("X-Artifact-Source", result.Source)
 	if result.Size > 0 {
 		w.Header().Set("X-Artifact-Size", fmt.Sprintf("%d", result.Size))
 	}
 	w.WriteHeader(http.StatusOK)
-	io.Copy(w, result.Reader)
+	io.Copy(w, body)
 }
 
 func (h *ProxyHandler) handleProxyHead(w http.ResponseWriter, r *http.Request) {

internal/database/helm_metadata.go

@@ -0,0 +1,44 @@
+package database
+
+import (
+	"context"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+)
+
+func (db *DB) InsertHelmMetadata(ctx context.Context, meta *provider.HelmMetadata) error {
+	_, err := db.Pool.Exec(ctx, `
+		INSERT INTO helm_metadata (repo_name, file_path, content_hash, name, version, chart_yaml)
+		VALUES ($1,$2,$3,$4,$5,$6)
+		ON CONFLICT (repo_name, file_path) DO NOTHING
+	`, meta.RepoName, meta.FilePath, meta.ContentHash, meta.Name, meta.Version, meta.ChartYAML)
+	return err
+}
+
+func (db *DB) DeleteHelmMetadata(ctx context.Context, repoName, filePath string) error {
+	_, err := db.Pool.Exec(ctx, `DELETE FROM helm_metadata WHERE repo_name = $1 AND file_path = $2`, repoName, filePath)
+	return err
+}
+
+func (db *DB) ListHelmMetadataEntries(ctx context.Context, repoName string) ([]provider.HelmMetadata, error) {
+	rows, err := db.Pool.Query(ctx, `
+		SELECT repo_name, file_path, content_hash, name, version, chart_yaml, created_at
+		FROM helm_metadata
+		WHERE repo_name = $1
+		ORDER BY name, version, file_path
+	`, repoName)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var result []provider.HelmMetadata
+	for rows.Next() {
+		var m provider.HelmMetadata
+		if err := rows.Scan(&m.RepoName, &m.FilePath, &m.ContentHash, &m.Name, &m.Version, &m.ChartYAML, &m.CreatedAt); err != nil {
+			return nil, err
+		}
+		result = append(result, m)
+	}
+	return result, rows.Err()
+}

internal/database/puppet_metadata.go

@@ -0,0 +1,46 @@
+package database
+
+import (
+	"context"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+)
+
+func (db *DB) InsertPuppetMetadata(ctx context.Context, meta *provider.PuppetMetadata) error {
+	_, err := db.Pool.Exec(ctx, `
+		INSERT INTO puppet_metadata (repo_name, file_path, content_hash, slug, version, metadata_json, file_size, file_md5)
+		VALUES ($1,$2,$3,$4,$5,$6,$7,$8)
+		ON CONFLICT (repo_name, file_path) DO NOTHING
+	`, meta.RepoName, meta.FilePath, meta.ContentHash, meta.Slug, meta.Version, meta.MetadataJSON, meta.Size, meta.MD5)
+	return err
+}
+
+func (db *DB) DeletePuppetMetadata(ctx context.Context, repoName, filePath string) error {
+	_, err := db.Pool.Exec(ctx, `DELETE FROM puppet_metadata WHERE repo_name = $1 AND file_path = $2`, repoName, filePath)
+	return err
+}
+
+// ListPuppetMetadataEntries returns a repo's releases, optionally narrowed to
+// one module slug (empty slug lists every module).
+func (db *DB) ListPuppetMetadataEntries(ctx context.Context, repoName, slug string) ([]provider.PuppetMetadata, error) {
+	rows, err := db.Pool.Query(ctx, `
+		SELECT repo_name, file_path, content_hash, slug, version, metadata_json, file_size, file_md5, created_at
+		FROM puppet_metadata
+		WHERE repo_name = $1 AND ($2 = '' OR slug = $2)
+		ORDER BY slug, file_path
+	`, repoName, slug)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var result []provider.PuppetMetadata
+	for rows.Next() {
+		var m provider.PuppetMetadata
+		if err := rows.Scan(&m.RepoName, &m.FilePath, &m.ContentHash, &m.Slug, &m.Version, &m.MetadataJSON, &m.Size, &m.MD5, &m.CreatedAt); err != nil {
+			return nil, err
+		}
+		result = append(result, m)
+	}
+	return result, rows.Err()
+}

internal/provider/helm/helm.go

@@ -1,12 +1,24 @@
 package helm
 
 import (
+	"archive/tar"
+	"compress/gzip"
 	"context"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
 	"net/http"
+	"net/url"
+	"path"
 	"strings"
+	"time"
+
+	"gopkg.in/yaml.v3"
 
 	"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"
 )
 
@@ -56,3 +68,203 @@ func (p *Provider) RewriteResponse(body []byte, remote models.Remote, proxyBaseU
 func (p *Provider) AuthHeaders(_ context.Context, remote models.Remote) (http.Header, error) {
 	return auth.BasicHeaders(remote), nil
 }
+
+// ValidateUpload stores charts flat by filename so index.yaml can reference
+// them with relative urls, as `helm repo index` does.
+func (p *Provider) ValidateUpload(filePath string) (storagePath, contentType string, err error) {
+	filename := path.Base(path.Clean("/" + filePath))
+	if !strings.HasSuffix(filename, ".tgz") || filename == ".tgz" {
+		return "", "", fmt.Errorf("file must be a .tgz chart package")
+	}
+	return filename, "application/gzip", nil
+}
+
+func (p *Provider) UploadResponse(storagePath, contentHash string, sizeBytes int64) map[string]any {
+	return map[string]any{
+		"filename":     storagePath,
+		"content_hash": contentHash,
+		"size_bytes":   sizeBytes,
+	}
+}
+
+func (p *Provider) AfterUpload(ctx context.Context, repoName, storagePath, contentHash string, blobs provider.BlobReader, db provider.MetadataStore) {
+	reader, _, err := blobs.Download(ctx, storage.BlobKey(strings.TrimPrefix(contentHash, "sha256:")))
+	if err != nil {
+		slog.Error("helm metadata: download failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	defer func() { _ = reader.Close() }()
+
+	meta, err := parseChart(reader)
+	if err != nil {
+		slog.Error("helm metadata: parse failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	if want := meta.Name + "-" + meta.Version + ".tgz"; storagePath != want {
+		slog.Error("helm metadata: filename does not match chart", "repo", repoName, "path", storagePath, "expected", want)
+		return
+	}
+	meta.RepoName = repoName
+	meta.FilePath = storagePath
+	meta.ContentHash = contentHash
+
+	store, ok := db.(provider.HelmMetadataStore)
+	if !ok {
+		slog.Error("helm metadata: store does not support helm metadata", "repo", repoName)
+		return
+	}
+	if err := store.InsertHelmMetadata(ctx, meta); err != nil {
+		slog.Error("helm metadata: insert failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	slog.Info("helm metadata: parsed", "repo", repoName, "name", meta.Name, "version", meta.Version)
+}
+
+func (p *Provider) AfterDelete(ctx context.Context, repoName, storagePath string, db provider.MetadataDeleter) error {
+	deleter, ok := db.(provider.HelmMetadataDeleter)
+	if !ok {
+		return nil
+	}
+	return deleter.DeleteHelmMetadata(ctx, repoName, storagePath)
+}
+
+func isIndexPath(p string) bool {
+	return strings.TrimPrefix(path.Clean("/"+p), "/") == "index.yaml"
+}
+
+func (p *Provider) ServeLocalIndex(w http.ResponseWriter, r *http.Request, files provider.FileStore, repoName, reqPath string) bool {
+	if !isIndexPath(reqPath) {
+		return false
+	}
+	body, err := p.GenerateLocalIndex(r.Context(), files, repoName, reqPath)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return true
+	}
+	w.Header().Set("Content-Type", "text/yaml")
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write(body)
+	return true
+}
+
+func (p *Provider) GenerateLocalIndex(ctx context.Context, files provider.FileStore, repoName, reqPath string) ([]byte, error) {
+	if !isIndexPath(reqPath) {
+		return nil, fmt.Errorf("unsupported index path: %q", reqPath)
+	}
+	reader, ok := files.(provider.HelmMetadataReader)
+	if !ok {
+		return nil, errors.New("helm metadata not available")
+	}
+	metas, err := reader.ListHelmMetadataEntries(ctx, repoName)
+	if err != nil {
+		return nil, err
+	}
+	return generateIndex(metas)
+}
+
+// generateIndex builds index.yaml from stored Chart.yaml documents; it is
+// stamped from the newest upload so every replica serves identical bytes.
+func generateIndex(metas []provider.HelmMetadata) ([]byte, error) {
+	entries := map[string][]map[string]yaml.Node{}
+	var newest time.Time
+	budget := provider.MaxAliasExpandedNodes
+	for _, m := range metas {
+		var raw map[string]yaml.Node
+		if err := yaml.Unmarshal([]byte(m.ChartYAML), &raw); err != nil {
+			return nil, fmt.Errorf("chart %s: %w", m.FilePath, err)
+		}
+		chart, err := provider.ExpandYAMLAliases(raw, &budget)
+		if err != nil {
+			slog.Warn("helm index: dropping chart", "chart", m.Name, "path", m.FilePath, "error", err)
+			continue
+		}
+		chart["name"] = node(m.Name)
+		chart["version"] = node(m.Version)
+		chart["urls"] = node([]string{url.PathEscape(m.FilePath)})
+		chart["digest"] = node(strings.TrimPrefix(m.ContentHash, "sha256:"))
+		chart["created"] = node(m.CreatedAt.UTC().Format(time.RFC3339Nano))
+		entries[m.Name] = append(entries[m.Name], chart)
+		if m.CreatedAt.After(newest) {
+			newest = m.CreatedAt
+		}
+	}
+	return yaml.Marshal(map[string]any{
+		"apiVersion": "v1",
+		"entries":    entries,
+		"generated":  newest.UTC().Format(time.RFC3339Nano),
+	})
+}
+
+func node(v any) yaml.Node {
+	var n yaml.Node
+	_ = n.Encode(v)
+	return n
+}
+
+const (
+	maxChartYAML    = 1 << 20
+	maxChartBytes   = 50 << 20
+	maxChartEntries = 10000
+)
+
+var errChartTooLarge = fmt.Errorf("chart archive exceeds %d decompressed bytes", maxChartBytes)
+
+type capReader struct {
+	r io.Reader
+	n int64
+}
+
+func (c *capReader) Read(p []byte) (int, error) {
+	if c.n <= 0 {
+		return 0, errChartTooLarge
+	}
+	if int64(len(p)) > c.n {
+		p = p[:c.n]
+	}
+	n, err := c.r.Read(p)
+	c.n -= int64(n)
+	return n, err
+}
+
+// parseChart reads the top-level <chart>/Chart.yaml from a packaged chart.
+func parseChart(r io.Reader) (*provider.HelmMetadata, error) {
+	zr, err := gzip.NewReader(r)
+	if err != nil {
+		return nil, err
+	}
+	tr := tar.NewReader(&capReader{r: zr, n: maxChartBytes})
+	for entries := 0; ; entries++ {
+		if entries >= maxChartEntries {
+			return nil, fmt.Errorf("chart archive exceeds %d entries", maxChartEntries)
+		}
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			return nil, errors.New("no Chart.yaml in chart archive")
+		}
+		if err != nil {
+			return nil, err
+		}
+		dir, file := path.Split(path.Clean(hdr.Name))
+		if file != "Chart.yaml" || strings.Count(dir, "/") != 1 {
+			continue
+		}
+		raw, err := io.ReadAll(io.LimitReader(tr, maxChartYAML+1))
+		if err != nil {
+			return nil, err
+		}
+		if len(raw) > maxChartYAML {
+			return nil, fmt.Errorf("parse Chart.yaml: exceeds %d bytes", maxChartYAML)
+		}
+		var chart struct {
+			Name    string `yaml:"name"`
+			Version string `yaml:"version"`
+		}
+		if err := yaml.Unmarshal(raw, &chart); err != nil {
+			return nil, fmt.Errorf("parse Chart.yaml: %w", err)
+		}
+		if chart.Name == "" || chart.Version == "" {
+			return nil, errors.New("chart metadata missing name or version")
+		}
+		return &provider.HelmMetadata{Name: chart.Name, Version: chart.Version, ChartYAML: string(raw)}, nil
+	}
+}

internal/provider/helm/helm_local_test.go

@@ -0,0 +1,236 @@
+package helm
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"context"
+	"io"
+	"net/http/httptest"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"gopkg.in/yaml.v3"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+)
+
+func chartTgz(t *testing.T, files map[string]string) []byte {
+	t.Helper()
+	var buf bytes.Buffer
+	zw := gzip.NewWriter(&buf)
+	tw := tar.NewWriter(zw)
+	for name, body := range files {
+		if err := tw.WriteHeader(&tar.Header{Name: name, Mode: 0o644, Size: int64(len(body))}); err != nil {
+			t.Fatal(err)
+		}
+		if _, err := tw.Write([]byte(body)); err != nil {
+			t.Fatal(err)
+		}
+	}
+	if err := tw.Close(); err != nil {
+		t.Fatal(err)
+	}
+	if err := zw.Close(); err != nil {
+		t.Fatal(err)
+	}
+	return buf.Bytes()
+}
+
+type fakeBlobs struct{ data []byte }
+
+func (f fakeBlobs) Download(context.Context, string) (io.ReadCloser, int64, error) {
+	return io.NopCloser(bytes.NewReader(f.data)), int64(len(f.data)), nil
+}
+
+type fakeStore struct {
+	inserted *provider.HelmMetadata
+	metas    []provider.HelmMetadata
+}
+
+func (f *fakeStore) InsertRPMMetadata(context.Context, *provider.RPMMetadata) error { return nil }
+func (f *fakeStore) InsertDebMetadata(context.Context, *provider.DebMetadata) error { return nil }
+func (f *fakeStore) InsertHelmMetadata(_ context.Context, m *provider.HelmMetadata) error {
+	f.inserted = m
+	return nil
+}
+func (f *fakeStore) ListHelmMetadataEntries(context.Context, string) ([]provider.HelmMetadata, error) {
+	return f.metas, nil
+}
+func (f *fakeStore) ListFilesByPrefix(context.Context, string, string) ([]provider.FileEntry, error) {
+	return nil, nil
+}
+func (f *fakeStore) ListPackages(context.Context, string) ([]string, error) { return nil, nil }
+
+func TestValidateUpload(t *testing.T) {
+	p := &Provider{}
+	for in, want := range map[string]string{
+		"mychart-0.1.0.tgz":        "mychart-0.1.0.tgz",
+		"charts/mychart-0.1.0.tgz": "mychart-0.1.0.tgz",
+		"../../mychart-0.1.0.tgz":  "mychart-0.1.0.tgz",
+	} {
+		sp, ct, err := p.ValidateUpload(in)
+		if err != nil || sp != want || ct != "application/gzip" {
+			t.Errorf("ValidateUpload(%q) = %q %q %v", in, sp, ct, err)
+		}
+	}
+	for _, bad := range []string{"index.yaml", "chart.tar.gz", ".tgz", ""} {
+		if _, _, err := p.ValidateUpload(bad); err == nil {
+			t.Errorf("ValidateUpload(%q) accepted", bad)
+		}
+	}
+}
+
+func TestAfterUploadParsesTopLevelChart(t *testing.T) {
+	data := chartTgz(t, map[string]string{
+		"mychart/charts/sub/Chart.yaml": "apiVersion: v2\nname: sub\nversion: 9.9.9\n",
+		"mychart/Chart.yaml":            "apiVersion: v2\nname: mychart\nversion: 1.0\ndescription: hi\n",
+		"mychart/values.yaml":           "a: 1\n",
+	})
+	store := &fakeStore{}
+	(&Provider{}).AfterUpload(context.Background(), "r", "mychart-1.0.tgz", "sha256:ab", fakeBlobs{data}, store)
+	m := store.inserted
+	if m == nil || m.Name != "mychart" || m.Version != "1.0" || m.FilePath != "mychart-1.0.tgz" || m.ContentHash != "sha256:ab" {
+		t.Fatalf("inserted %+v", m)
+	}
+}
+
+func TestAfterUploadRejectsChartWithoutMetadata(t *testing.T) {
+	store := &fakeStore{}
+	data := chartTgz(t, map[string]string{"mychart/Chart.yaml": "apiVersion: v2\nname: mychart\n"})
+	(&Provider{}).AfterUpload(context.Background(), "r", "x.tgz", "sha256:ab", fakeBlobs{data}, store)
+	if store.inserted != nil {
+		t.Fatal("chart without version was recorded")
+	}
+	(&Provider{}).AfterUpload(context.Background(), "r", "x.tgz", "sha256:ab", fakeBlobs{[]byte("not gzip")}, store)
+	if store.inserted != nil {
+		t.Fatal("non-gzip upload was recorded")
+	}
+}
+
+func TestServeLocalIndex(t *testing.T) {
+	t1 := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)
+	t2 := t1.Add(time.Hour)
+	store := &fakeStore{metas: []provider.HelmMetadata{
+		{FilePath: "mychart-1.0.tgz", ContentHash: "sha256:aa", Name: "mychart", Version: "1.0", CreatedAt: t1,
+			ChartYAML: "apiVersion: v2\nname: mychart\nversion: 1.0\nappVersion: \"2\"\ndescription: hi\n"},
+		{FilePath: "other-0.2.0.tgz", ContentHash: "sha256:bb", Name: "other", Version: "0.2.0", CreatedAt: t2,
+			ChartYAML: "apiVersion: v2\nname: other\nversion: 0.2.0\n"},
+	}}
+	p := &Provider{}
+
+	if p.ServeLocalIndex(httptest.NewRecorder(), httptest.NewRequest("GET", "/", nil), store, "r", "mychart-1.0.tgz") {
+		t.Fatal("chart path handled as index")
+	}
+	rec := httptest.NewRecorder()
+	if !p.ServeLocalIndex(rec, httptest.NewRequest("GET", "/", nil), store, "r", "./index.yaml") {
+		t.Fatal("index.yaml not handled")
+	}
+	if rec.Code != 200 || rec.Header().Get("Content-Type") != "text/yaml" {
+		t.Fatalf("code=%d ct=%q", rec.Code, rec.Header().Get("Content-Type"))
+	}
+
+	var idx struct {
+		APIVersion string `yaml:"apiVersion"`
+		Generated  string `yaml:"generated"`
+		Entries    map[string][]map[string]any
+	}
+	if err := yaml.Unmarshal(rec.Body.Bytes(), &idx); err != nil {
+		t.Fatal(err)
+	}
+	if idx.APIVersion != "v1" || idx.Generated != t2.Format(time.RFC3339Nano) {
+		t.Errorf("header %+v", idx)
+	}
+	e := idx.Entries["mychart"][0]
+	if e["digest"] != "aa" || e["description"] != "hi" || e["appVersion"] != "2" || e["apiVersion"] != "v2" {
+		t.Errorf("entry %v", e)
+	}
+	if urls, _ := e["urls"].([]any); len(urls) != 1 || urls[0] != "mychart-1.0.tgz" {
+		t.Errorf("urls %v", e["urls"])
+	}
+	if e["version"] != "1.0" || e["name"] != "mychart" {
+		t.Errorf("version must stay a string: %#v", e["version"])
+	}
+	if len(idx.Entries["other"]) != 1 {
+		t.Errorf("other entries %v", idx.Entries["other"])
+	}
+
+	again, err := p.GenerateLocalIndex(context.Background(), store, "r", "index.yaml")
+	if err != nil || !bytes.Equal(again, rec.Body.Bytes()) {
+		t.Errorf("index not deterministic: %v", err)
+	}
+}
+
+func TestAfterUploadRejectsFilenameMismatch(t *testing.T) {
+	store := &fakeStore{}
+	data := chartTgz(t, map[string]string{"mychart/Chart.yaml": "apiVersion: v2\nname: mychart\nversion: 1.0.0\n"})
+	(&Provider{}).AfterUpload(context.Background(), "r", "other-1.0.0.tgz", "sha256:ab", fakeBlobs{data}, store)
+	if store.inserted != nil {
+		t.Fatal("chart indexed under a filename that does not match name-version")
+	}
+}
+
+func TestParseChartLimits(t *testing.T) {
+	chart := "apiVersion: v2\nname: c\nversion: 1.0.0\n"
+	for name, tc := range map[string]struct {
+		files map[string]string
+		want  string
+	}{
+		"decompressed": {map[string]string{"c/a.bin": strings.Repeat("\x00", maxChartBytes+1)}, "decompressed bytes"},
+		"chart yaml":   {map[string]string{"c/Chart.yaml": chart + "#" + strings.Repeat("x", maxChartYAML)}, "Chart.yaml: exceeds"},
+	} {
+		_, err := parseChart(bytes.NewReader(chartTgz(t, tc.files)))
+		if err == nil || !strings.Contains(err.Error(), tc.want) {
+			t.Errorf("%s: err = %v, want %q", name, err, tc.want)
+		}
+	}
+
+	var buf bytes.Buffer
+	zw := gzip.NewWriter(&buf)
+	tw := tar.NewWriter(zw)
+	for i := 0; i <= maxChartEntries; i++ {
+		_ = tw.WriteHeader(&tar.Header{Name: "c/templates/" + strconv.Itoa(i), Mode: 0o644})
+	}
+	_ = tw.WriteHeader(&tar.Header{Name: "c/Chart.yaml", Mode: 0o644, Size: int64(len(chart))})
+	_, _ = tw.Write([]byte(chart))
+	_ = tw.Close()
+	_ = zw.Close()
+	if _, err := parseChart(&buf); err == nil || !strings.Contains(err.Error(), "entries") {
+		t.Errorf("entries: err = %v", err)
+	}
+
+	if m, err := parseChart(bytes.NewReader(chartTgz(t, map[string]string{"c/Chart.yaml": chart}))); err != nil || m.Name != "c" {
+		t.Errorf("valid chart: %v %v", m, err)
+	}
+}
+
+func TestIndexEscapesURLs(t *testing.T) {
+	out, err := generateIndex([]provider.HelmMetadata{{FilePath: "my chart-1.0.0.tgz", Name: "my chart", Version: "1.0.0", ChartYAML: "name: x\n"}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(string(out), "my%20chart-1.0.0.tgz") {
+		t.Errorf("url not escaped:\n%s", out)
+	}
+}
+
+func TestIndexExpandsAliasesBeforeOverride(t *testing.T) {
+	body, err := generateIndex([]provider.HelmMetadata{{
+		FilePath: "app-1.0.0.tgz", ContentHash: "sha256:aa", Name: "app", Version: "1.0.0",
+		ChartYAML: "apiVersion: v2\nname: app\nversion: &v 1.0.0\nappVersion: *v\n",
+	}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	var idx struct {
+		Entries map[string][]map[string]any
+	}
+	if err := yaml.Unmarshal(body, &idx); err != nil {
+		t.Fatalf("index does not parse: %v\n%s", err, body)
+	}
+	if e := idx.Entries["app"]; len(e) != 1 || e[0]["appVersion"] != "1.0.0" {
+		t.Errorf("entries %v", idx.Entries)
+	}
+}

internal/provider/nuget/nuget.go

@@ -0,0 +1,85 @@
+// Package nuget proxies a NuGet v3 feed: the service index, registration pages
+// and flat container indexes are mutable, .nupkg/.nuspec downloads immutable.
+package nuget
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"git.unkin.net/unkin/artifactapi/internal/auth"
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+func init() {
+	provider.Register(&Provider{})
+}
+
+// serviceIndex is the path clients use as their source URL; it maps to base_url.
+const serviceIndex = "index.json"
+
+type Provider struct{}
+
+func (p *Provider) Type() models.PackageType { return models.PackageNuGet }
+
+func (p *Provider) Classify(path string) provider.Mutability {
+	if isPackage(path) {
+		return provider.Immutable
+	}
+	return provider.Mutable
+}
+
+func (p *Provider) ContentType(path string) string {
+	switch {
+	case strings.HasSuffix(path, ".nupkg"):
+		return "application/octet-stream"
+	case strings.HasSuffix(path, ".nuspec"):
+		return "application/xml"
+	}
+	return "application/json"
+}
+
+// UpstreamURL maps index.json to base_url (the upstream service index) and any
+// other path to the same path on the base_url's origin, where nuget.org serves
+// v3-flatcontainer/ and v3/registration*/.
+func (p *Provider) UpstreamURL(remote models.Remote, path string) string {
+	path = strings.TrimLeft(path, "/")
+	if path == serviceIndex {
+		return remote.BaseURL
+	}
+	return origin(remote.BaseURL) + "/" + path
+}
+
+func (p *Provider) RewriteResponse(_ []byte, _ models.Remote, _ string) ([]byte, error) {
+	return nil, nil
+}
+
+// RewriteServed points upstream-origin URLs in cached JSON back at this remote.
+// It runs per request because the URLs must name the requesting host.
+func (p *Provider) RewriteServed(body []byte, remote models.Remote, proxyBaseURL string) []byte {
+	from := origin(remote.BaseURL)
+	if from == "" || !json.Valid(body) {
+		return body
+	}
+	to := strings.TrimRight(proxyBaseURL, "/") + "/api/v1/remote/" + remote.Name
+	return []byte(strings.ReplaceAll(string(body), from, to))
+}
+
+func (p *Provider) AuthHeaders(_ context.Context, remote models.Remote) (http.Header, error) {
+	return auth.BasicHeaders(remote), nil
+}
+
+func origin(baseURL string) string {
+	u, err := url.Parse(baseURL)
+	if err != nil || u.Host == "" {
+		return ""
+	}
+	return u.Scheme + "://" + u.Host
+}
+
+func isPackage(path string) bool {
+	return strings.HasSuffix(path, ".nupkg") || strings.HasSuffix(path, ".nuspec")
+}

internal/provider/nuget/nuget_test.go

@@ -0,0 +1,68 @@
+package nuget
+
+import (
+	"testing"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+var _ provider.ServeRewriter = (*Provider)(nil)
+
+var nugetOrg = models.Remote{Name: "nuget-org", BaseURL: "https://api.nuget.org/v3/index.json"}
+
+func TestClassify(t *testing.T) {
+	p := &Provider{}
+	tests := []struct {
+		path string
+		want provider.Mutability
+	}{
+		{"v3-flatcontainer/newtonsoft.json/13.0.3/newtonsoft.json.13.0.3.nupkg", provider.Immutable},
+		{"v3-flatcontainer/newtonsoft.json/13.0.3/newtonsoft.json.nuspec", provider.Immutable},
+		{"v3-flatcontainer/newtonsoft.json/index.json", provider.Mutable},
+		{"v3/registration5-gz-semver2/newtonsoft.json/index.json", provider.Mutable},
+		{"index.json", 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 TestUpstreamURL(t *testing.T) {
+	p := &Provider{}
+	tests := []struct {
+		path, want string
+	}{
+		{"index.json", "https://api.nuget.org/v3/index.json"},
+		{"/index.json", "https://api.nuget.org/v3/index.json"},
+		{"v3-flatcontainer/serilog/index.json", "https://api.nuget.org/v3-flatcontainer/serilog/index.json"},
+		{"v3/registration5-gz-semver2/serilog/index.json", "https://api.nuget.org/v3/registration5-gz-semver2/serilog/index.json"},
+	}
+	for _, tt := range tests {
+		if got := p.UpstreamURL(nugetOrg, tt.path); got != tt.want {
+			t.Errorf("UpstreamURL(%q) = %q, want %q", tt.path, got, tt.want)
+		}
+	}
+}
+
+func TestRewriteServed(t *testing.T) {
+	p := &Provider{}
+	body := `{"resources":[` +
+		`{"@id":"https://api.nuget.org/v3-flatcontainer/","@type":"PackageBaseAddress/3.0.0"},` +
+		`{"@id":"https://azuresearch-usnc.nuget.org/query","@type":"SearchQueryService"}]}`
+	want := `{"resources":[` +
+		`{"@id":"http://aa.example:8000/api/v1/remote/nuget-org/v3-flatcontainer/","@type":"PackageBaseAddress/3.0.0"},` +
+		`{"@id":"https://azuresearch-usnc.nuget.org/query","@type":"SearchQueryService"}]}`
+	if got := string(p.RewriteServed([]byte(body), nugetOrg, "http://aa.example:8000/")); got != want {
+		t.Errorf("RewriteServed =\n%s\nwant\n%s", got, want)
+	}
+	if got := string(p.RewriteServed([]byte(body), models.Remote{Name: "x"}, "http://aa.example")); got != body {
+		t.Error("remote without a parseable base_url must pass the body through")
+	}
+	cert := "\x30\x82https://api.nuget.org"
+	if got := string(p.RewriteServed([]byte(cert), nugetOrg, "http://aa.example")); got != cert {
+		t.Error("non-JSON bodies must pass through untouched")
+	}
+}

internal/provider/provider.go

@@ -75,6 +75,13 @@ type RemoteServer interface {
 	ServeRemote(w http.ResponseWriter, r *http.Request, remote models.Remote, path, proxyBaseURL string, store RemoteMetadataStore) bool
 }
 
+// ServeRewriter rewrites a cached mutable remote response per request, for
+// indexes whose URLs must name the requesting host and so cannot be rewritten
+// before caching.
+type ServeRewriter interface {
+	RewriteServed(body []byte, remote models.Remote, proxyBaseURL string) []byte
+}
+
 // RemoteMetadataStore is the persistence surface a RemoteServer needs to cache
 // and read the metadata it derives per upstream asset. *database.DB satisfies it.
 type RemoteMetadataStore interface {
@@ -240,3 +247,53 @@ func Get(t models.PackageType) (Provider, error) {
 func All() map[models.PackageType]Provider {
 	return registry
 }
+
+type HelmMetadataStore interface {
+	InsertHelmMetadata(ctx context.Context, meta *HelmMetadata) error
+}
+
+type HelmMetadataDeleter interface {
+	DeleteHelmMetadata(ctx context.Context, repoName, filePath string) error
+}
+
+type HelmMetadataReader interface {
+	ListHelmMetadataEntries(ctx context.Context, repoName string) ([]HelmMetadata, error)
+}
+
+// HelmMetadata is a local chart's Chart.yaml, kept verbatim so index.yaml
+// entries carry every field helm reads.
+type HelmMetadata struct {
+	RepoName    string
+	FilePath    string
+	ContentHash string
+	Name        string
+	Version     string
+	ChartYAML   string
+	CreatedAt   time.Time
+}
+
+type PuppetMetadataStore interface {
+	InsertPuppetMetadata(ctx context.Context, meta *PuppetMetadata) error
+}
+
+type PuppetMetadataDeleter interface {
+	DeletePuppetMetadata(ctx context.Context, repoName, filePath string) error
+}
+
+type PuppetMetadataReader interface {
+	ListPuppetMetadataEntries(ctx context.Context, repoName, slug string) ([]PuppetMetadata, error)
+}
+
+// PuppetMetadata is a local module release; MetadataJSON is the tarball's
+// metadata.json verbatim so Forge release objects carry every field.
+type PuppetMetadata struct {
+	RepoName     string
+	FilePath     string
+	ContentHash  string
+	Slug         string
+	Version      string
+	MetadataJSON string
+	Size         int64
+	MD5          string
+	CreatedAt    time.Time
+}

internal/provider/puppet/local.go

@@ -0,0 +1,393 @@
+package puppet
+
+import (
+	"archive/tar"
+	"compress/gzip"
+	"context"
+	"crypto/md5"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"net/http"
+	"net/url"
+	"path"
+	"regexp"
+	"slices"
+	"strconv"
+	"strings"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+	"git.unkin.net/unkin/artifactapi/internal/storage"
+)
+
+const filesPrefix = "v3/files/"
+
+// releaseRe matches <owner>-<name>-<semver>, the Forge release slug and the
+// tarball basename that `puppet module build` produces.
+var releaseRe = regexp.MustCompile(`^([a-z0-9]+)-([a-z][a-z0-9_]*)-(\d+\.\d+\.\d+(?:-[0-9a-z.-]+)?(?:\+[0-9a-z.-]+)?)$`)
+
+func parseRelease(s string) (slug, version string, ok bool) {
+	m := releaseRe.FindStringSubmatch(strings.ToLower(s))
+	if m == nil {
+		return "", "", false
+	}
+	return m[1] + "-" + m[2], m[3], true
+}
+
+func normalizeSlug(s string) string {
+	return strings.ToLower(strings.ReplaceAll(s, "/", "-"))
+}
+
+// ValidateUpload stores tarballs under v3/files/ so Forge file_uri downloads
+// resolve straight to the stored file.
+func (p *Provider) ValidateUpload(filePath string) (storagePath, contentType string, err error) {
+	filename := strings.ToLower(path.Base(path.Clean("/" + filePath)))
+	if _, _, ok := parseRelease(strings.TrimSuffix(filename, ".tar.gz")); !ok || !strings.HasSuffix(filename, ".tar.gz") {
+		return "", "", fmt.Errorf("file must be named <owner>-<module>-<version>.tar.gz")
+	}
+	return filesPrefix + filename, "application/gzip", nil
+}
+
+func (p *Provider) UploadResponse(storagePath, contentHash string, sizeBytes int64) map[string]any {
+	return map[string]any{
+		"filename":     path.Base(storagePath),
+		"content_hash": contentHash,
+		"size_bytes":   sizeBytes,
+	}
+}
+
+func (p *Provider) AfterUpload(ctx context.Context, repoName, storagePath, contentHash string, blobs provider.BlobReader, db provider.MetadataStore) {
+	reader, size, err := blobs.Download(ctx, storage.BlobKey(strings.TrimPrefix(contentHash, "sha256:")))
+	if err != nil {
+		slog.Error("puppet metadata: download failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	defer func() { _ = reader.Close() }()
+	if size > maxModuleTarball {
+		slog.Error("puppet metadata: tarball too large", "repo", repoName, "path", storagePath, "size", size)
+		return
+	}
+
+	hash := md5.New()
+	src := io.TeeReader(io.LimitReader(reader, maxModuleTarball), hash)
+	meta, err := parseModule(src)
+	if err != nil {
+		slog.Error("puppet metadata: parse failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	if _, err := io.Copy(io.Discard, src); err != nil {
+		slog.Error("puppet metadata: read failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	slug, version, _ := parseRelease(strings.TrimSuffix(path.Base(storagePath), ".tar.gz"))
+	if meta.Slug != slug || meta.Version != version {
+		slog.Error("puppet metadata: metadata.json does not match filename", "repo", repoName, "path", storagePath, "name", meta.Slug, "version", meta.Version)
+		return
+	}
+	meta.RepoName = repoName
+	meta.FilePath = storagePath
+	meta.ContentHash = contentHash
+	meta.Size = size
+	meta.MD5 = hex.EncodeToString(hash.Sum(nil))
+
+	store, ok := db.(provider.PuppetMetadataStore)
+	if !ok {
+		slog.Error("puppet metadata: store does not support puppet metadata", "repo", repoName)
+		return
+	}
+	if err := store.InsertPuppetMetadata(ctx, meta); err != nil {
+		slog.Error("puppet metadata: insert failed", "repo", repoName, "path", storagePath, "error", err)
+		return
+	}
+	slog.Info("puppet metadata: parsed", "repo", repoName, "module", meta.Slug, "version", meta.Version)
+}
+
+func (p *Provider) AfterDelete(ctx context.Context, repoName, storagePath string, db provider.MetadataDeleter) error {
+	deleter, ok := db.(provider.PuppetMetadataDeleter)
+	if !ok {
+		return nil
+	}
+	return deleter.DeletePuppetMetadata(ctx, repoName, storagePath)
+}
+
+const maxMetadataJSON = 1 << 20
+
+var (
+	maxModuleTarball int64 = 100 << 20
+	maxModuleScan    int64 = 200 << 20
+)
+
+// parseModule reads the top-level <dir>/metadata.json from a module tarball,
+// scanning at most maxModuleScan decompressed bytes.
+func parseModule(r io.Reader) (*provider.PuppetMetadata, error) {
+	zr, err := gzip.NewReader(r)
+	if err != nil {
+		return nil, err
+	}
+	scan := &io.LimitedReader{R: zr, N: maxModuleScan}
+	tr := tar.NewReader(scan)
+	for {
+		hdr, err := tr.Next()
+		if scan.N <= 0 {
+			return nil, errors.New("module tarball exceeds decompressed scan limit before metadata.json")
+		}
+		if err == io.EOF {
+			return nil, errors.New("no metadata.json in module tarball")
+		}
+		if err != nil {
+			return nil, err
+		}
+		dir, file := path.Split(strings.TrimPrefix(path.Clean(hdr.Name), "./"))
+		if hdr.Typeflag != tar.TypeReg || file != "metadata.json" || strings.Count(dir, "/") != 1 {
+			continue
+		}
+		body, err := io.ReadAll(io.LimitReader(tr, maxMetadataJSON))
+		if err != nil {
+			return nil, err
+		}
+		var md struct {
+			Name    string `json:"name"`
+			Version string `json:"version"`
+		}
+		if err := json.Unmarshal(body, &md); err != nil {
+			return nil, fmt.Errorf("parse metadata.json: %w", err)
+		}
+		if md.Name == "" || md.Version == "" {
+			return nil, errors.New("metadata.json missing name or version")
+		}
+		return &provider.PuppetMetadata{Slug: normalizeSlug(md.Name), Version: md.Version, MetadataJSON: string(body)}, nil
+	}
+}
+
+func (p *Provider) ServeLocalIndex(w http.ResponseWriter, r *http.Request, files provider.FileStore, repoName, reqPath string) bool {
+	clean := strings.TrimPrefix(path.Clean("/"+reqPath), "/")
+	var list func(slug string) ([]provider.PuppetMetadata, error)
+	if reader, ok := files.(provider.PuppetMetadataReader); ok {
+		list = func(slug string) ([]provider.PuppetMetadata, error) {
+			metas, err := reader.ListPuppetMetadataEntries(r.Context(), repoName, slug)
+			sortReleases(metas)
+			return metas, err
+		}
+	} else {
+		list = func(string) ([]provider.PuppetMetadata, error) {
+			return nil, errors.New("puppet metadata not available")
+		}
+	}
+
+	switch {
+	case clean == "v3/releases":
+		serveReleaseList(w, r, list)
+	case strings.HasPrefix(clean, "v3/releases/"):
+		slug, version, ok := parseRelease(strings.TrimPrefix(clean, "v3/releases/"))
+		if !ok {
+			notFound(w)
+			return true
+		}
+		metas, err := list(slug)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return true
+		}
+		for _, m := range metas {
+			if m.Version == version {
+				writeJSON(w, releaseObject(m))
+				return true
+			}
+		}
+		notFound(w)
+	case strings.HasPrefix(clean, "v3/modules/"):
+		slug := normalizeSlug(strings.TrimPrefix(clean, "v3/modules/"))
+		metas, err := list(slug)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return true
+		}
+		if len(metas) == 0 {
+			notFound(w)
+			return true
+		}
+		writeJSON(w, moduleObject(metas))
+	default:
+		return false
+	}
+	return true
+}
+
+func (p *Provider) GenerateLocalIndex(ctx context.Context, files provider.FileStore, repoName, path string) ([]byte, error) {
+	return nil, fmt.Errorf("puppet local index generation for virtual repos not supported")
+}
+
+func serveReleaseList(w http.ResponseWriter, r *http.Request, list func(string) ([]provider.PuppetMetadata, error)) {
+	q := r.URL.Query()
+	slug := normalizeSlug(q.Get("module"))
+	limit, err := strconv.Atoi(q.Get("limit"))
+	if err != nil || limit <= 0 {
+		limit = 20
+	}
+	limit = min(limit, 100)
+	offset, err := strconv.Atoi(q.Get("offset"))
+	if err != nil || offset < 0 {
+		offset = 0
+	}
+
+	metas, err := list(slug)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	offset = min(offset, len(metas))
+	results := []map[string]any{}
+	for _, m := range metas[offset : offset+min(limit, len(metas)-offset)] {
+		results = append(results, releaseObject(m))
+	}
+
+	page := func(off int) any {
+		if off < 0 || off >= len(metas) && off != 0 {
+			return nil
+		}
+		v := url.Values{"limit": {strconv.Itoa(limit)}, "offset": {strconv.Itoa(off)}}
+		if slug != "" {
+			v.Set("module", slug)
+		}
+		return "/v3/releases?" + v.Encode()
+	}
+	var previous any
+	if offset > 0 {
+		previous = page(max(offset-limit, 0))
+	}
+	writeJSON(w, map[string]any{
+		"pagination": map[string]any{
+			"limit":    limit,
+			"offset":   offset,
+			"first":    page(0),
+			"previous": previous,
+			"current":  page(offset),
+			"next":     page(offset + limit),
+			"total":    len(metas),
+		},
+		"results": results,
+	})
+}
+
+func owner(slug string) map[string]any {
+	name, _, _ := strings.Cut(slug, "-")
+	return map[string]any{"uri": "/v3/users/" + name, "slug": name, "username": name}
+}
+
+func moduleRef(slug string) map[string]any {
+	_, name, _ := strings.Cut(slug, "-")
+	return map[string]any{"uri": "/v3/modules/" + slug, "slug": slug, "name": name, "deprecated_at": nil, "owner": owner(slug)}
+}
+
+const forgeTime = "2006-01-02 15:04:05 -0700"
+
+func releaseObject(m provider.PuppetMetadata) map[string]any {
+	slug := m.Slug + "-" + m.Version
+	return map[string]any{
+		"uri":         "/v3/releases/" + slug,
+		"slug":        slug,
+		"module":      moduleRef(m.Slug),
+		"version":     m.Version,
+		"metadata":    json.RawMessage(m.MetadataJSON),
+		"tags":        []string{},
+		"supported":   false,
+		"pdk":         false,
+		"file_uri":    "/" + m.FilePath,
+		"file_size":   m.Size,
+		"file_md5":    m.MD5,
+		"file_sha256": strings.TrimPrefix(m.ContentHash, "sha256:"),
+		"downloads":   0,
+		"readme":      nil,
+		"changelog":   nil,
+		"license":     nil,
+		"created_at":  m.CreatedAt.Format(forgeTime),
+		"updated_at":  m.CreatedAt.Format(forgeTime),
+		"deleted_at":  nil,
+	}
+}
+
+// moduleObject expects metas sorted newest version first.
+func moduleObject(metas []provider.PuppetMetadata) map[string]any {
+	obj := moduleRef(metas[0].Slug)
+	releases := make([]map[string]any, 0, len(metas))
+	for _, m := range metas {
+		slug := m.Slug + "-" + m.Version
+		releases = append(releases, map[string]any{
+			"uri": "/v3/releases/" + slug, "slug": slug, "version": m.Version,
+			"file_uri": "/" + m.FilePath, "file_size": m.Size, "supported": false,
+			"created_at": m.CreatedAt.Format(forgeTime), "deleted_at": nil,
+		})
+	}
+	obj["current_release"] = releaseObject(metas[0])
+	obj["releases"] = releases
+	obj["downloads"] = 0
+	obj["created_at"] = metas[len(metas)-1].CreatedAt.Format(forgeTime)
+	obj["updated_at"] = metas[0].CreatedAt.Format(forgeTime)
+	return obj
+}
+
+func writeJSON(w http.ResponseWriter, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	enc := json.NewEncoder(w)
+	enc.SetEscapeHTML(false)
+	_ = enc.Encode(v)
+}
+
+func notFound(w http.ResponseWriter) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusNotFound)
+	_, _ = io.WriteString(w, `{"message":"404 Not Found","errors":["The requested resource could not be found"]}`)
+}
+
+// sortReleases orders by module slug, then newest semver first.
+func sortReleases(metas []provider.PuppetMetadata) {
+	slices.SortStableFunc(metas, func(a, b provider.PuppetMetadata) int {
+		if c := strings.Compare(a.Slug, b.Slug); c != 0 {
+			return c
+		}
+		return compareSemver(b.Version, a.Version)
+	})
+}
+
+func compareSemver(a, b string) int {
+	a, _, _ = strings.Cut(a, "+")
+	b, _, _ = strings.Cut(b, "+")
+	aCore, aPre, aHasPre := strings.Cut(a, "-")
+	bCore, bPre, bHasPre := strings.Cut(b, "-")
+	if c := compareIdents(strings.Split(aCore, "."), strings.Split(bCore, ".")); c != 0 {
+		return c
+	}
+	switch {
+	case aHasPre && !bHasPre:
+		return -1
+	case !aHasPre && bHasPre:
+		return 1
+	}
+	return compareIdents(strings.Split(aPre, "."), strings.Split(bPre, "."))
+}
+
+func compareIdents(a, b []string) int {
+	for i := 0; i < len(a) && i < len(b); i++ {
+		an, aErr := strconv.Atoi(a[i])
+		bn, bErr := strconv.Atoi(b[i])
+		var c int
+		switch {
+		case aErr == nil && bErr == nil:
+			c = an - bn
+		case aErr == nil:
+			c = -1
+		case bErr == nil:
+			c = 1
+		default:
+			c = strings.Compare(a[i], b[i])
+		}
+		if c != 0 {
+			return c
+		}
+	}
+	return len(a) - len(b)
+}

internal/provider/puppet/local_test.go

@@ -0,0 +1,301 @@
+package puppet
+
+import (
+	"archive/tar"
+	"bytes"
+	"compress/gzip"
+	"context"
+	"crypto/md5"
+	"encoding/hex"
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"git.unkin.net/unkin/artifactapi/internal/provider"
+)
+
+func moduleTarball(t *testing.T, dir, metadata string) []byte {
+	t.Helper()
+	var buf bytes.Buffer
+	zw := gzip.NewWriter(&buf)
+	tw := tar.NewWriter(zw)
+	for name, body := range map[string]string{dir + "/metadata.json": metadata, dir + "/manifests/init.pp": "class hello {}\n"} {
+		if err := tw.WriteHeader(&tar.Header{Name: name, Mode: 0o644, Size: int64(len(body))}); err != nil {
+			t.Fatal(err)
+		}
+		_, _ = tw.Write([]byte(body))
+	}
+	_ = tw.Close()
+	_ = zw.Close()
+	return buf.Bytes()
+}
+
+const helloMetadata = `{"name":"unkin-hello","version":"0.1.0","dependencies":[{"name":"puppetlabs/stdlib","version_requirement":">= 4.0.0"}]}`
+
+type fakeBlobs struct{ data []byte }
+
+func (f fakeBlobs) Download(context.Context, string) (io.ReadCloser, int64, error) {
+	return io.NopCloser(bytes.NewReader(f.data)), int64(len(f.data)), nil
+}
+
+type fakeStore struct{ inserted *provider.PuppetMetadata }
+
+func (f *fakeStore) InsertRPMMetadata(context.Context, *provider.RPMMetadata) error { return nil }
+func (f *fakeStore) InsertDebMetadata(context.Context, *provider.DebMetadata) error { return nil }
+func (f *fakeStore) InsertPuppetMetadata(_ context.Context, m *provider.PuppetMetadata) error {
+	f.inserted = m
+	return nil
+}
+
+type fakeReader struct{ metas []provider.PuppetMetadata }
+
+func (f fakeReader) ListPuppetMetadataEntries(_ context.Context, _, slug string) ([]provider.PuppetMetadata, error) {
+	var out []provider.PuppetMetadata
+	for _, m := range f.metas {
+		if slug == "" || m.Slug == slug {
+			out = append(out, m)
+		}
+	}
+	return out, nil
+}
+func (fakeReader) ListFilesByPrefix(context.Context, string, string) ([]provider.FileEntry, error) {
+	return nil, nil
+}
+func (fakeReader) ListPackages(context.Context, string) ([]string, error) { return nil, nil }
+
+func TestValidateUpload(t *testing.T) {
+	p := &Provider{}
+	sp, ct, err := p.ValidateUpload("some/dir/Unkin-hello-0.1.0.tar.gz")
+	if err != nil || sp != "v3/files/unkin-hello-0.1.0.tar.gz" || ct != "application/gzip" {
+		t.Errorf("sp=%q ct=%q err=%v", sp, ct, err)
+	}
+	for _, bad := range []string{"hello-0.1.0.tar.gz", "unkin-hello-0.1.tar.gz", "unkin-hello-0.1.0.zip", "unkin-Hello_x-0.1.0.tgz"} {
+		if _, _, err := p.ValidateUpload(bad); err == nil {
+			t.Errorf("%q accepted", bad)
+		}
+	}
+}
+
+func TestAfterUploadRecordsMetadata(t *testing.T) {
+	raw := moduleTarball(t, "unkin-hello-0.1.0", helloMetadata)
+	store := &fakeStore{}
+	(&Provider{}).AfterUpload(context.Background(), "forge", "v3/files/unkin-hello-0.1.0.tar.gz", "sha256:abc", fakeBlobs{raw}, store)
+	m := store.inserted
+	if m == nil {
+		t.Fatal("nothing inserted")
+	}
+	sum := md5.Sum(raw)
+	if m.Slug != "unkin-hello" || m.Version != "0.1.0" || m.MD5 != hex.EncodeToString(sum[:]) || m.Size != int64(len(raw)) || m.MetadataJSON != helloMetadata {
+		t.Errorf("got %+v", m)
+	}
+}
+
+func TestAfterUploadRejectsMismatchedFilename(t *testing.T) {
+	raw := moduleTarball(t, "unkin-hello-0.2.0", `{"name":"unkin-hello","version":"0.2.0"}`)
+	store := &fakeStore{}
+	(&Provider{}).AfterUpload(context.Background(), "forge", "v3/files/unkin-hello-0.1.0.tar.gz", "sha256:abc", fakeBlobs{raw}, store)
+	if store.inserted != nil {
+		t.Error("mismatched version indexed")
+	}
+}
+
+func TestParseModuleRequiresTopLevelMetadata(t *testing.T) {
+	if _, err := parseModule(bytes.NewReader(moduleTarball(t, "a/b", helloMetadata))); err == nil {
+		t.Error("nested metadata.json accepted")
+	}
+	if _, err := parseModule(bytes.NewReader(moduleTarball(t, "x", `{"name":"unkin-hello"}`))); err == nil {
+		t.Error("missing version accepted")
+	}
+}
+
+func tarballOf(t *testing.T, entries ...*tar.Header) []byte {
+	t.Helper()
+	var buf bytes.Buffer
+	zw := gzip.NewWriter(&buf)
+	tw := tar.NewWriter(zw)
+	for _, h := range entries {
+		if err := tw.WriteHeader(h); err != nil {
+			t.Fatal(err)
+		}
+		if h.Typeflag == tar.TypeReg {
+			body := helloMetadata
+			if !strings.HasSuffix(h.Name, "metadata.json") {
+				body = strings.Repeat("x", int(h.Size))
+			}
+			_, _ = tw.Write([]byte(body))
+		}
+	}
+	_ = tw.Close()
+	_ = zw.Close()
+	return buf.Bytes()
+}
+
+func TestParseModuleSkipsNonRegularMetadata(t *testing.T) {
+	raw := tarballOf(t,
+		&tar.Header{Name: "unkin-hello-0.1.0/metadata.json", Typeflag: tar.TypeSymlink, Linkname: "/etc/passwd"},
+		&tar.Header{Name: "unkin-hello-0.1.0/metadata.json/", Typeflag: tar.TypeDir, Mode: 0o755},
+		&tar.Header{Name: "unkin-hello-0.1.0/metadata.json", Typeflag: tar.TypeReg, Mode: 0o644, Size: int64(len(helloMetadata))},
+	)
+	meta, err := parseModule(bytes.NewReader(raw))
+	if err != nil || meta.Slug != "unkin-hello" || meta.Version != "0.1.0" {
+		t.Fatalf("got %v, %v", meta, err)
+	}
+}
+
+func TestParseModuleCapsDecompressedScan(t *testing.T) {
+	defer func(n int64) { maxModuleScan = n }(maxModuleScan)
+	maxModuleScan = 64 << 10
+	raw := tarballOf(t,
+		&tar.Header{Name: "unkin-hello-0.1.0/big", Typeflag: tar.TypeReg, Mode: 0o644, Size: 1 << 20},
+		&tar.Header{Name: "unkin-hello-0.1.0/metadata.json", Typeflag: tar.TypeReg, Mode: 0o644, Size: int64(len(helloMetadata))},
+	)
+	if _, err := parseModule(bytes.NewReader(raw)); err == nil || !strings.Contains(err.Error(), "scan limit") {
+		t.Fatalf("expected scan limit error, got %v", err)
+	}
+	maxModuleScan = 2 << 20
+	if _, err := parseModule(bytes.NewReader(raw)); err != nil {
+		t.Fatalf("under cap: %v", err)
+	}
+}
+
+func TestAfterUploadCapsTarballSize(t *testing.T) {
+	defer func(n int64) { maxModuleTarball = n }(maxModuleTarball)
+	raw := moduleTarball(t, "unkin-hello-0.1.0", helloMetadata)
+	maxModuleTarball = int64(len(raw)) - 1
+	store := &fakeStore{}
+	(&Provider{}).AfterUpload(context.Background(), "forge", "v3/files/unkin-hello-0.1.0.tar.gz", "sha256:abc", fakeBlobs{raw}, store)
+	if store.inserted != nil {
+		t.Error("oversized tarball indexed")
+	}
+	maxModuleTarball = int64(len(raw))
+	(&Provider{}).AfterUpload(context.Background(), "forge", "v3/files/unkin-hello-0.1.0.tar.gz", "sha256:abc", fakeBlobs{raw}, store)
+	if store.inserted == nil {
+		t.Error("tarball at cap not indexed")
+	}
+}
+
+func TestReleaseListClampsPagination(t *testing.T) {
+	files := releases("0.1.0", "0.2.0", "0.3.0")
+	for _, q := range []string{"offset=9223372036854775807", "offset=9223372036854775807&limit=9223372036854775807", "offset=-5&limit=-5", "limit=9223372036854775807"} {
+		code, body := get(t, files, "v3/releases?module=unkin-hello&"+q)
+		if code != http.StatusOK {
+			t.Fatalf("%s: code %d", q, code)
+		}
+		pg := body["pagination"].(map[string]any)
+		if l := pg["limit"].(float64); l < 1 || l > 100 {
+			t.Errorf("%s: limit %v", q, l)
+		}
+		if o := pg["offset"].(float64); o < 0 || o > 3 {
+			t.Errorf("%s: offset %v", q, o)
+		}
+	}
+	_, body := get(t, files, "v3/releases?module=unkin-hello&offset=9223372036854775807")
+	if len(body["results"].([]any)) != 0 || body["pagination"].(map[string]any)["next"] != nil {
+		t.Errorf("past-end page: %v", body)
+	}
+}
+
+func get(t *testing.T, files provider.FileStore, target string) (int, map[string]any) {
+	t.Helper()
+	rec := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/x/"+target, nil)
+	path, _, _ := strings.Cut(target, "?")
+	if !(&Provider{}).ServeLocalIndex(rec, req, files, "forge", path) {
+		return 0, nil
+	}
+	var body map[string]any
+	_ = json.Unmarshal(rec.Body.Bytes(), &body)
+	return rec.Code, body
+}
+
+func releases(versions ...string) fakeReader {
+	var f fakeReader
+	for i, v := range versions {
+		f.metas = append(f.metas, provider.PuppetMetadata{
+			FilePath: "v3/files/unkin-hello-" + v + ".tar.gz", ContentHash: "sha256:feed", Slug: "unkin-hello",
+			Version: v, MetadataJSON: `{"name":"unkin-hello","version":"` + v + `"}`, MD5: "m" + v,
+			CreatedAt: time.Unix(int64(i), 0),
+		})
+	}
+	f.metas = append(f.metas, provider.PuppetMetadata{Slug: "other-mod", Version: "9.9.9", MetadataJSON: `{}`})
+	return f
+}
+
+func TestReleaseListPaginatesNewestFirst(t *testing.T) {
+	files := releases("0.1.0", "0.10.0", "0.2.0", "1.0.0-rc.1", "1.0.0")
+	code, body := get(t, files, "v3/releases?module=unkin/hello&limit=2")
+	if code != http.StatusOK {
+		t.Fatalf("code %d", code)
+	}
+	results := body["results"].([]any)
+	pg := body["pagination"].(map[string]any)
+	if len(results) != 2 || results[0].(map[string]any)["version"] != "1.0.0" || results[1].(map[string]any)["version"] != "1.0.0-rc.1" {
+		t.Fatalf("page 1: %v", results)
+	}
+	if pg["total"] != float64(5) || pg["next"] != "/v3/releases?limit=2&module=unkin-hello&offset=2" || pg["previous"] != nil {
+		t.Errorf("pagination: %v", pg)
+	}
+
+	_, body = get(t, files, "v3/releases?module=unkin-hello&limit=2&offset=4")
+	results = body["results"].([]any)
+	pg = body["pagination"].(map[string]any)
+	if len(results) != 1 || results[0].(map[string]any)["version"] != "0.1.0" || pg["next"] != nil || pg["previous"] != "/v3/releases?limit=2&module=unkin-hello&offset=2" {
+		t.Errorf("last page: %v %v", results, pg)
+	}
+
+	_, body = get(t, files, "v3/releases?module=nobody-none")
+	if len(body["results"].([]any)) != 0 {
+		t.Error("unknown module returned results")
+	}
+}
+
+func TestReleaseObject(t *testing.T) {
+	code, body := get(t, releases("0.1.0"), "v3/releases/unkin-hello-0.1.0")
+	if code != http.StatusOK {
+		t.Fatalf("code %d", code)
+	}
+	if body["file_uri"] != "/v3/files/unkin-hello-0.1.0.tar.gz" || body["file_md5"] != "m0.1.0" || body["file_sha256"] != "feed" {
+		t.Errorf("release: %v", body)
+	}
+	if body["metadata"].(map[string]any)["name"] != "unkin-hello" || body["module"].(map[string]any)["owner"].(map[string]any)["username"] != "unkin" {
+		t.Errorf("release refs: %v", body)
+	}
+	if code, _ := get(t, releases("0.1.0"), "v3/releases/unkin-hello-0.2.0"); code != http.StatusNotFound {
+		t.Errorf("missing version: %d", code)
+	}
+}
+
+func TestModuleObject(t *testing.T) {
+	code, body := get(t, releases("0.9.0", "0.10.0"), "v3/modules/unkin-hello")
+	if code != http.StatusOK {
+		t.Fatalf("code %d", code)
+	}
+	if body["slug"] != "unkin-hello" || body["name"] != "hello" || body["current_release"].(map[string]any)["version"] != "0.10.0" || len(body["releases"].([]any)) != 2 {
+		t.Errorf("module: %v", body)
+	}
+	if code, _ := get(t, releases(), "v3/modules/unkin-missing"); code != http.StatusNotFound {
+		t.Errorf("missing module: %d", code)
+	}
+}
+
+func TestFilesFallThrough(t *testing.T) {
+	if code, _ := get(t, releases(), "v3/files/unkin-hello-0.1.0.tar.gz"); code != 0 {
+		t.Error("file downloads must fall through to the stored file")
+	}
+}
+
+func TestCompareSemver(t *testing.T) {
+	ordered := []string{"0.1.0", "0.2.0", "0.10.0", "1.0.0-alpha", "1.0.0-alpha.1", "1.0.0-beta", "1.0.0-beta.2", "1.0.0-beta.11", "1.0.0", "1.0.1+build"}
+	for i := 1; i < len(ordered); i++ {
+		if compareSemver(ordered[i-1], ordered[i]) >= 0 || compareSemver(ordered[i], ordered[i-1]) <= 0 {
+			t.Errorf("%s should sort before %s", ordered[i-1], ordered[i])
+		}
+	}
+	if compareSemver("1.0.0+a", "1.0.0+b") != 0 {
+		t.Error("build metadata must not affect precedence")
+	}
+}

internal/provider/yamlalias.go

@@ -0,0 +1,46 @@
+package provider
+
+import (
+	"errors"
+
+	"gopkg.in/yaml.v3"
+)
+
+const MaxAliasExpandedNodes = 100000
+
+// ExpandYAMLAliases inlines alias targets and drops anchors so a node map
+// stays valid when copied away from the document that held its anchors;
+// budget caps nodes reached through aliases against alias bombs.
+func ExpandYAMLAliases(m map[string]yaml.Node, budget *int) (map[string]yaml.Node, error) {
+	var expand func(n *yaml.Node, viaAlias bool) (*yaml.Node, error)
+	expand = func(n *yaml.Node, viaAlias bool) (*yaml.Node, error) {
+		if viaAlias {
+			*budget--
+			if *budget < 0 {
+				return nil, errors.New("yaml aliases expand to too many nodes")
+			}
+		}
+		if n.Kind == yaml.AliasNode {
+			return expand(n.Alias, true)
+		}
+		c := *n
+		c.Anchor = ""
+		c.Content = make([]*yaml.Node, len(n.Content))
+		for i, ch := range n.Content {
+			var err error
+			if c.Content[i], err = expand(ch, viaAlias); err != nil {
+				return nil, err
+			}
+		}
+		return &c, nil
+	}
+	out := make(map[string]yaml.Node, len(m))
+	for k, v := range m {
+		e, err := expand(&v, false)
+		if err != nil {
+			return nil, err
+		}
+		out[k] = *e
+	}
+	return out, nil
+}

internal/server/server.go

@@ -29,6 +29,7 @@ import (
 	_ "git.unkin.net/unkin/artifactapi/internal/provider/goproxy"
 	_ "git.unkin.net/unkin/artifactapi/internal/provider/helm"
 	_ "git.unkin.net/unkin/artifactapi/internal/provider/npm"
+	_ "git.unkin.net/unkin/artifactapi/internal/provider/nuget"
 	_ "git.unkin.net/unkin/artifactapi/internal/provider/puppet"
 	_ "git.unkin.net/unkin/artifactapi/internal/provider/pypi"
 	"git.unkin.net/unkin/artifactapi/internal/provider/rpm"

internal/virtual/engine.go

@@ -29,15 +29,24 @@ type Engine struct {
 
 	mergeTTL time.Duration
 
-	sf  singleflight.Group
-	mu  sync.Mutex
-	rpm map[string]*rpmGen
+	sf   singleflight.Group
+	mu   sync.Mutex
+	gens map[string]*repoGen
 }
 
-// rpmGen holds a virtual's current merge plus the previous one, so a client
-// holding the previous repomd can still fetch its content-hashed data files.
-type rpmGen struct {
-	cur, prev *RPMRepo
+// mergedRepo is a merged index document plus the files it references.
+type mergedRepo interface {
+	index() []byte
+	files() map[string][]byte
+}
+
+func (r *RPMRepo) index() []byte            { return r.Repomd }
+func (r *RPMRepo) files() map[string][]byte { return r.Files }
+
+// repoGen holds a virtual's current merge plus the previous one, so a client
+// holding the previous index can still fetch the files it references.
+type repoGen struct {
+	cur, prev mergedRepo
 	at        time.Time
 }
 
@@ -217,54 +226,57 @@ func (e *Engine) fetchRPM(ctx context.Context, virt models.Virtual, path string)
 	if !strings.HasPrefix(path, "repodata/") {
 		return nil, "", ErrNotFound
 	}
+	key := "rpm\x00" + virt.Name
 	if path != "repodata/repomd.xml" {
-		if body, ok := e.cachedRPMFile(virt.Name, path); ok {
+		if body, ok := e.cachedFile(key, path); ok {
 			return body, "application/gzip", nil
 		}
 	}
 
-	repo, err := e.mergedRPM(ctx, virt)
+	repo, err := e.merged(ctx, key, func(ctx context.Context) (mergedRepo, error) {
+		return e.mergeRPM(ctx, virt)
+	})
 	if err != nil {
 		return nil, "", err
 	}
 	if path == "repodata/repomd.xml" {
-		return repo.Repomd, "application/xml", nil
+		return repo.index(), "application/xml", nil
 	}
-	if body, ok := repo.Files[path]; ok {
+	if body, ok := repo.files()[path]; ok {
 		return body, "application/gzip", nil
 	}
 	return nil, "", ErrNotFound
 }
 
-// mergedRPM returns the virtual's merge, reusing it for mergeTTL and
-// collapsing concurrent merges of the same virtual into one.
+// merged returns the merge cached under key, reusing it for mergeTTL and
+// collapsing concurrent merges of the same key into one.
 // ponytail: per-replica cache; behind a non-sticky LB a data request landing on
 // another replica re-merges and 404s if a member changed in between. Move to the
 // shared redis cache if that shows up.
-func (e *Engine) mergedRPM(ctx context.Context, virt models.Virtual) (*RPMRepo, error) {
+func (e *Engine) merged(ctx context.Context, key string, merge func(context.Context) (mergedRepo, error)) (mergedRepo, error) {
 	e.mu.Lock()
-	g := e.rpm[virt.Name]
+	g := e.gens[key]
 	if g != nil && time.Since(g.at) < e.mergeTTL {
 		e.mu.Unlock()
 		return g.cur, nil
 	}
 	e.mu.Unlock()
 
-	v, err, _ := e.sf.Do(virt.Name, func() (any, error) {
-		repo, err := e.mergeRPM(context.WithoutCancel(ctx), virt)
+	v, err, _ := e.sf.Do(key, func() (any, error) {
+		repo, err := merge(context.WithoutCancel(ctx))
 		if err != nil {
 			return nil, err
 		}
 		e.mu.Lock()
 		defer e.mu.Unlock()
-		if e.rpm == nil {
-			e.rpm = map[string]*rpmGen{}
+		if e.gens == nil {
+			e.gens = map[string]*repoGen{}
 		}
-		g := e.rpm[virt.Name]
+		g := e.gens[key]
 		switch {
 		case g == nil:
-			e.rpm[virt.Name] = &rpmGen{cur: repo, at: time.Now()}
-		case string(g.cur.Repomd) == string(repo.Repomd):
+			e.gens[key] = &repoGen{cur: repo, at: time.Now()}
+		case string(g.cur.index()) == string(repo.index()):
 			g.at = time.Now()
 			repo = g.cur
 		default:
@@ -275,18 +287,31 @@ func (e *Engine) mergedRPM(ctx context.Context, virt models.Virtual) (*RPMRepo,
 	if err != nil {
 		return nil, err
 	}
-	return v.(*RPMRepo), nil
+	return v.(mergedRepo), nil
 }
 
 func (e *Engine) mergeRPM(ctx context.Context, virt models.Virtual) (*RPMRepo, error) {
-	members := make([]RPMMember, len(virt.Members))
+	members, err := fetchMembers(virt, func(name string) (*RPMMember, error) { return e.rpmMember(ctx, name) })
+	if err != nil {
+		return nil, err
+	}
+	repo, err := MergeRPM(members)
+	if err != nil {
+		return nil, fmt.Errorf("merge rpm repodata: %w", err)
+	}
+	return repo, nil
+}
+
+// fetchMembers reads every member in parallel, failing if any member fails.
+func fetchMembers[T any](virt models.Virtual, fetch func(name string) (*T, error)) ([]T, error) {
+	members := make([]T, len(virt.Members))
 	errs := make([]error, len(virt.Members))
 	var wg sync.WaitGroup
 	for i, name := range virt.Members {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			m, err := e.rpmMember(ctx, name)
+			m, err := fetch(name)
 			if err != nil {
 				errs[i] = fmt.Errorf("member %q: %w", name, err)
 				return
@@ -299,26 +324,21 @@ func (e *Engine) mergeRPM(ctx context.Context, virt models.Virtual) (*RPMRepo, e
 	if err := errors.Join(errs...); err != nil {
 		return nil, fmt.Errorf("virtual %q: %v", virt.Name, err)
 	}
-
-	repo, err := MergeRPM(members)
-	if err != nil {
-		return nil, fmt.Errorf("merge rpm repodata: %w", err)
-	}
-	return repo, nil
+	return members, nil
 }
 
-func (e *Engine) cachedRPMFile(virt, path string) ([]byte, bool) {
+func (e *Engine) cachedFile(key, path string) ([]byte, bool) {
 	e.mu.Lock()
 	defer e.mu.Unlock()
-	g := e.rpm[virt]
+	g := e.gens[key]
 	if g == nil {
 		return nil, false
 	}
-	for _, r := range []*RPMRepo{g.cur, g.prev} {
+	for _, r := range []mergedRepo{g.cur, g.prev} {
 		if r == nil {
 			continue
 		}
-		if body, ok := r.Files[path]; ok {
+		if body, ok := r.files()[path]; ok {
 			return body, true
 		}
 	}

internal/virtual/engine_test.go

@@ -156,3 +156,53 @@ func TestMemberRedirect(t *testing.T) {
 		}
 	}
 }
+
+type fakeRepo struct {
+	idx string
+	fs  map[string][]byte
+}
+
+func (r *fakeRepo) index() []byte            { return []byte(r.idx) }
+func (r *fakeRepo) files() map[string][]byte { return r.fs }
+
+func genRepo(gen string) func(context.Context) (mergedRepo, error) {
+	return func(context.Context) (mergedRepo, error) {
+		return &fakeRepo{idx: gen, fs: map[string][]byte{gen + ".gz": []byte(gen), "fixed": []byte(gen)}}, nil
+	}
+}
+
+func TestMergedRetainsPreviousGeneration(t *testing.T) {
+	e := fakeEngine(nil)
+	for _, gen := range []string{"g1", "g2", "g3"} {
+		if _, err := e.merged(context.Background(), "k", genRepo(gen)); err != nil {
+			t.Fatal(err)
+		}
+	}
+	for path, want := range map[string]string{"g3.gz": "g3", "g2.gz": "g2", "fixed": "g3"} {
+		if body, ok := e.cachedFile("k", path); !ok || string(body) != want {
+			t.Errorf("%s: got (%q, %v), want %q", path, body, ok, want)
+		}
+	}
+	if _, ok := e.cachedFile("k", "g1.gz"); ok {
+		t.Error("generation two merges back must be dropped")
+	}
+}
+
+func TestMergedReusesWithinTTLAndIsolatesKeys(t *testing.T) {
+	e := fakeEngine(nil)
+	e.mergeTTL = time.Minute
+	for _, step := range []struct{ key, gen, want string }{
+		{"a", "a1", "a1"}, {"b", "b1", "b1"}, {"a", "a2", "a1"},
+	} {
+		repo, err := e.merged(context.Background(), step.key, genRepo(step.gen))
+		if err != nil || string(repo.index()) != step.want {
+			t.Fatalf("%s: got %v (err %v), want %s", step.key, repo, err, step.want)
+		}
+	}
+	if _, ok := e.cachedFile("b", "a1.gz"); ok {
+		t.Error("key b served key a's file")
+	}
+	if _, ok := e.cachedFile("c", "a1.gz"); ok {
+		t.Error("unknown key served a file")
+	}
+}

internal/virtual/helm_merger.go

@@ -2,10 +2,14 @@ package virtual
 
 import (
 	"fmt"
+	"log/slog"
+	"maps"
+	"slices"
 	"strings"
 
 	"gopkg.in/yaml.v3"
 
+	"git.unkin.net/unkin/artifactapi/internal/provider"
 	"git.unkin.net/unkin/artifactapi/pkg/models"
 )
 
@@ -16,22 +20,17 @@ func init() {
 type HelmMerger struct{}
 
 type helmIndex struct {
-	APIVersion string                        `yaml:"apiVersion"`
-	Entries    map[string][]helmChartVersion `yaml:"entries"`
-	Generated  string                        `yaml:"generated,omitempty"`
-}
-
-type helmChartVersion struct {
-	Name    string   `yaml:"name"`
-	Version string   `yaml:"version"`
-	URLs    []string `yaml:"urls"`
-	rest    map[string]any
+	APIVersion string                            `yaml:"apiVersion"`
+	Entries    map[string][]map[string]yaml.Node `yaml:"entries"`
+	Generated  string                            `yaml:"generated,omitempty"`
 }
 
+// MergeIndexes keeps each chart version's fields as raw nodes so digest,
+// apiVersion and the rest survive the merge untouched; only urls are rewritten.
 func (m *HelmMerger) MergeIndexes(members []MemberIndex, proxyBaseURL string) ([]byte, error) {
 	merged := &helmIndex{
 		APIVersion: "v1",
-		Entries:    make(map[string][]helmChartVersion),
+		Entries:    make(map[string][]map[string]yaml.Node),
 	}
 
 	seen := map[string]map[string]bool{}
@@ -42,47 +41,38 @@ func (m *HelmMerger) MergeIndexes(members []MemberIndex, proxyBaseURL string) ([
 			continue
 		}
 
-		for chart, versions := range idx.Entries {
+		budget := provider.MaxAliasExpandedNodes
+		for _, chart := range slices.Sorted(maps.Keys(idx.Entries)) {
+			versions := idx.Entries[chart]
 			if seen[chart] == nil {
 				seen[chart] = map[string]bool{}
 			}
-			for _, ver := range versions {
-				key := chart + ":" + ver.Version
-				if seen[chart][ver.Version] {
+			for _, raw := range versions {
+				ver, err := provider.ExpandYAMLAliases(raw, &budget)
+				if err != nil {
+					slog.Warn("helm merge: dropping chart entry", "member", member.RemoteName, "chart", chart, "error", err)
 					continue
 				}
-				seen[chart][ver.Version] = true
+				version := ver["version"].Value
+				if seen[chart][version] {
+					continue
+				}
+				seen[chart][version] = true
 
-				if proxyBaseURL != "" {
-					routePrefix := "remote"
-					if member.RepoType == "local" {
-						routePrefix = "local"
+				if urlsNode, ok := ver["urls"]; ok && proxyBaseURL != "" {
+					var urls []string
+					if err := urlsNode.Decode(&urls); err != nil {
+						continue
 					}
-					baseHost := extractHost(member.BaseURL)
-
-					for i, u := range ver.URLs {
-						if strings.HasPrefix(u, "http://") || strings.HasPrefix(u, "https://") {
-							if baseHost != "" && extractHost(u) != baseHost {
-								continue
-							}
-							relPath := extractPathRelativeToBase(u, member.BaseURL)
-							ver.URLs[i] = fmt.Sprintf("%s/api/v1/%s/%s/%s",
-								strings.TrimRight(proxyBaseURL, "/"),
-								routePrefix,
-								member.RemoteName,
-								relPath)
-						} else {
-							ver.URLs[i] = fmt.Sprintf("%s/api/v1/%s/%s/%s",
-								strings.TrimRight(proxyBaseURL, "/"),
-								routePrefix,
-								member.RemoteName,
-								u)
-						}
+					rewriteHelmURLs(urls, member, proxyBaseURL)
+					var n yaml.Node
+					if err := n.Encode(urls); err != nil {
+						return nil, err
 					}
+					ver["urls"] = n
 				}
 
 				merged.Entries[chart] = append(merged.Entries[chart], ver)
-				_ = key
 			}
 		}
 	}
@@ -90,6 +80,34 @@ func (m *HelmMerger) MergeIndexes(members []MemberIndex, proxyBaseURL string) ([
 	return yaml.Marshal(merged)
 }
 
+func rewriteHelmURLs(urls []string, member MemberIndex, proxyBaseURL string) {
+	routePrefix := "remote"
+	if member.RepoType == "local" {
+		routePrefix = "local"
+	}
+	baseHost := extractHost(member.BaseURL)
+
+	for i, u := range urls {
+		if strings.HasPrefix(u, "http://") || strings.HasPrefix(u, "https://") {
+			if baseHost != "" && extractHost(u) != baseHost {
+				continue
+			}
+			relPath := extractPathRelativeToBase(u, member.BaseURL)
+			urls[i] = fmt.Sprintf("%s/api/v1/%s/%s/%s",
+				strings.TrimRight(proxyBaseURL, "/"),
+				routePrefix,
+				member.RemoteName,
+				relPath)
+		} else {
+			urls[i] = fmt.Sprintf("%s/api/v1/%s/%s/%s",
+				strings.TrimRight(proxyBaseURL, "/"),
+				routePrefix,
+				member.RemoteName,
+				u)
+		}
+	}
+}
+
 func extractHost(rawURL string) string {
 	idx := strings.Index(rawURL, "://")
 	if idx == -1 {

internal/virtual/helm_merger_test.go

@@ -1,9 +1,12 @@
 package virtual_test
 
 import (
+	"fmt"
 	"strings"
 	"testing"
 
+	"gopkg.in/yaml.v3"
+
 	"git.unkin.net/unkin/artifactapi/internal/virtual"
 )
 
@@ -122,3 +125,129 @@ entries:
 		t.Error("expected fallback repo to be excluded for duplicate")
 	}
 }
+
+func TestHelmMerger_PreservesChartFields(t *testing.T) {
+	m := &virtual.HelmMerger{}
+	body := []byte(`apiVersion: v1
+entries:
+  app:
+    - apiVersion: v2
+      name: app
+      version: "1.0"
+      appVersion: "3.1"
+      description: in-house
+      digest: deadbeef
+      urls:
+        - app-1.0.tgz
+`)
+	result, err := m.MergeIndexes([]virtual.MemberIndex{{RemoteName: "charts", RepoType: "local", Body: body}}, "https://proxy.example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	out := string(result)
+	for _, want := range []string{
+		"digest: deadbeef",
+		"apiVersion: v2",
+		`appVersion: "3.1"`,
+		"description: in-house",
+		`version: "1.0"`,
+		"https://proxy.example.com/api/v1/local/charts/app-1.0.tgz",
+	} {
+		if !strings.Contains(out, want) {
+			t.Errorf("merged index missing %q:\n%s", want, out)
+		}
+	}
+}
+
+func TestHelmMerger_ExpandsAliasesAcrossDedupe(t *testing.T) {
+	m := &virtual.HelmMerger{}
+	first := []byte(`apiVersion: v1
+entries:
+  app:
+    - version: "1.0"
+      urls: [app-1.0.tgz]
+`)
+	second := []byte(`apiVersion: v1
+entries:
+  app:
+    - version: "1.0"
+      maintainers: &team
+        - name: ops
+      urls: [app-1.0.tgz]
+    - version: "2.0"
+      maintainers: *team
+      urls: [app-2.0.tgz]
+`)
+	result, err := m.MergeIndexes([]virtual.MemberIndex{
+		{RemoteName: "a", RepoType: "local", Body: first},
+		{RemoteName: "b", RepoType: "local", Body: second},
+	}, "https://proxy.example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var idx struct {
+		Entries map[string][]struct {
+			Version     string `yaml:"version"`
+			Maintainers []struct {
+				Name string `yaml:"name"`
+			} `yaml:"maintainers"`
+		} `yaml:"entries"`
+	}
+	if err := yaml.Unmarshal(result, &idx); err != nil {
+		t.Fatalf("merged index does not parse: %v\n%s", err, result)
+	}
+	app := idx.Entries["app"]
+	if len(app) != 2 || app[1].Version != "2.0" || len(app[1].Maintainers) != 1 || app[1].Maintainers[0].Name != "ops" {
+		t.Errorf("alias not expanded: %+v\n%s", app, result)
+	}
+}
+
+func TestHelmMerger_DropsAliasBomb(t *testing.T) {
+	m := &virtual.HelmMerger{}
+	body := []byte(`apiVersion: v1
+entries:
+  app:
+    - version: "1.0"
+      a: &a [x, x, x, x, x, x, x, x, x, x]
+      b: &b [*a, *a, *a, *a, *a, *a, *a, *a, *a, *a]
+      c: &c [*b, *b, *b, *b, *b, *b, *b, *b, *b, *b]
+      d: &d [*c, *c, *c, *c, *c, *c, *c, *c, *c, *c]
+      e: &e [*d, *d, *d, *d, *d, *d, *d, *d, *d, *d]
+      urls: [app-1.0.tgz]
+`)
+	result, err := m.MergeIndexes([]virtual.MemberIndex{{RemoteName: "a", RepoType: "local", Body: body}}, "https://proxy.example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(string(result), "app-1.0.tgz") {
+		t.Errorf("alias bomb entry was kept")
+	}
+}
+
+func TestHelmMerger_LargeIndexWithoutAliasesIsComplete(t *testing.T) {
+	var b strings.Builder
+	b.WriteString("apiVersion: v1\nentries:\n")
+	for c := 0; c < 100; c++ {
+		fmt.Fprintf(&b, "  chart%d:\n", c)
+		for v := 0; v < 100; v++ {
+			fmt.Fprintf(&b, "    - name: chart%d\n      version: \"1.0.%d\"\n      description: d\n      maintainers: [{name: ops, email: ops@example.com}]\n      urls: [chart%d-1.0.%d.tgz]\n", c, v, c, v)
+		}
+	}
+	result, err := (&virtual.HelmMerger{}).MergeIndexes([]virtual.MemberIndex{{RemoteName: "a", RepoType: "local", Body: []byte(b.String())}}, "https://proxy.example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var idx struct {
+		Entries map[string][]map[string]any `yaml:"entries"`
+	}
+	if err := yaml.Unmarshal(result, &idx); err != nil {
+		t.Fatal(err)
+	}
+	total := 0
+	for _, vs := range idx.Entries {
+		total += len(vs)
+	}
+	if len(idx.Entries) != 100 || total != 10000 {
+		t.Errorf("got %d charts, %d versions; want 100, 10000", len(idx.Entries), total)
+	}
+}

migrations/0004_puppet_metadata.sql

@@ -0,0 +1,15 @@
+CREATE TABLE IF NOT EXISTS puppet_metadata (
+	id            BIGSERIAL PRIMARY KEY,
+	repo_name     TEXT NOT NULL,
+	file_path     TEXT NOT NULL,
+	content_hash  TEXT NOT NULL,
+	slug          TEXT NOT NULL,
+	version       TEXT NOT NULL,
+	metadata_json TEXT NOT NULL,
+	file_size     BIGINT NOT NULL DEFAULT 0,
+	file_md5      TEXT NOT NULL,
+	created_at    TIMESTAMPTZ DEFAULT NOW(),
+	UNIQUE(repo_name, file_path)
+);
+
+CREATE INDEX IF NOT EXISTS idx_puppet_metadata_repo_slug ON puppet_metadata(repo_name, slug);

migrations/0005_helm_metadata.sql

@@ -0,0 +1,13 @@
+CREATE TABLE IF NOT EXISTS helm_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,
+	chart_yaml   TEXT NOT NULL,
+	created_at   TIMESTAMPTZ DEFAULT NOW(),
+	UNIQUE(repo_name, file_path)
+);
+
+CREATE INDEX IF NOT EXISTS idx_helm_metadata_repo ON helm_metadata(repo_name);

pkg/models/package_type.go

@@ -17,6 +17,7 @@ const (
 	PackageTerraform    PackageType = "terraform"
 	PackageGoProxy      PackageType = "goproxy"
 	PackageCargo        PackageType = "cargo"
+	PackageNuGet        PackageType = "nuget"
 	PackageGitHubRPM    PackageType = "github_rpm"
 	PackageGitHubDeb    PackageType = "github_deb"
 	PackageGitHubAlpine PackageType = "github_alpine"
@@ -35,6 +36,7 @@ var validPackageTypes = map[PackageType]bool{
 	PackageTerraform:    true,
 	PackageGoProxy:      true,
 	PackageCargo:        true,
+	PackageNuGet:        true,
 	PackageGitHubRPM:    true,
 	PackageGitHubDeb:    true,
 	PackageGitHubAlpine: true,

pkg/models/package_type_test.go

@@ -19,6 +19,7 @@ func TestPackageTypeValid(t *testing.T) {
 		models.PackageTerraform,
 		models.PackageGoProxy,
 		models.PackageCargo,
+		models.PackageNuGet,
 		models.PackageGitHubRPM,
 		models.PackageGitHubDeb,
 		models.PackageGitHubAlpine,

ui/src/components/UsageInstructions.tsx

@@ -167,12 +167,23 @@ docker push        ${host}/${name}/myapp:latest`,
     case 'helm':
       return [
         {
-          title: 'Add the Helm repo',
+          title: isLocal ? 'Add the Helm repo (index.yaml auto-generated)' : 'Add the Helm repo',
           language: 'bash',
-          code: `helm repo add ${name} ${proxy}/
+          code: `helm repo add ${name} ${isLocal ? `${url}/api/v1/local/${name}` : proxy}/
 helm repo update
 helm install <release> ${name}/<chart>`,
         },
+        ...(isLocal
+          ? [
+              {
+                title: 'Publish a chart',
+                language: 'bash',
+                code: `helm package ./mychart
+curl -fsSL --upload-file mychart-0.1.0.tgz \\
+  ${url}/api/v2/remotes/${name}/files/mychart-0.1.0.tgz`,
+              },
+            ]
+          : []),
       ];
 
     case 'alpine':
@@ -243,14 +254,40 @@ index = "sparse+${proxy}/"`,
         },
       ];
 
+    case 'nuget':
+      return [
+        {
+          title: 'Use this feed instead of nuget.org',
+          language: 'xml',
+          code: `<!-- nuget.config -->
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="${name}" value="${proxy}/index.json" protocolVersion="3" />
+  </packageSources>
+</configuration>`,
+          note: 'Serve artifactapi over HTTPS: NuGet rejects the repository signatures resource over plain HTTP.',
+        },
+      ];
+
     case 'puppet':
       return [
         {
-          title: 'Install a module from the Forge proxy',
+          title: isLocal ? 'Install a module from this forge' : 'Install a module from the Forge proxy',
           language: 'bash',
           code: `puppet module install <author>-<module> \\
-  --module_repository ${proxy}`,
+  --module_repository ${isLocal ? `${url}/api/v1/local/${name}` : proxy}`,
         },
+        ...(isLocal
+          ? [
+              {
+                title: 'Publish a module (versions are immutable)',
+                language: 'bash',
+                code: `puppet module build && curl -fsSL --upload-file pkg/<author>-<module>-<version>.tar.gz \\
+  ${url}/api/v2/remotes/${name}/files/<author>-<module>-<version>.tar.gz`,
+              },
+            ]
+          : []),
       ];
 
     case 'deb':

ui/src/pages/Locals.tsx

@@ -18,6 +18,7 @@ const typeColors: Record<string, 'blue' | 'green' | 'yellow' | 'red' | 'default'
   terraform: 'blue',
   goproxy: 'green',
   cargo: 'yellow',
+  nuget: 'blue',
 };
 
 export function Locals() {

ui/src/pages/Remotes.tsx

@@ -18,6 +18,7 @@ const typeColors: Record<string, 'blue' | 'green' | 'yellow' | 'red' | 'default'
   terraform: 'blue',
   goproxy: 'green',
   cargo: 'yellow',
+  nuget: 'blue',
 };
 
 export function Remotes() {