Evict remote objects from every cache layer (#128)

Evicting a remote object only deleted its Postgres row. The S3 index and the Redis TTL/ETag keys survived, so stale mirror metadata such as EPEL repodata kept being served.

- evict the artifact row, S3 index and Redis keys via `Engine.Evict`
- evict a directory with `<dir>/*`; other wildcards return 400, unknown remotes 404
- wait on the per-path fetch lock for single-path evicts; return 503 on timeout or a Redis error
- wildcard evicts take no lock; a fetch already in flight may re-cache its path
- return S3 list errors from `DeletePrefix` instead of deleting nothing

Reviewed-on: #128
Co-authored-by: unkin-agent <unkin-agent@unkin.net>
Co-committed-by: unkin-agent <unkin-agent@unkin.net>

internal/api/v2/objects.go

@@ -1,6 +1,8 @@
 package v2
 
 import (
+	"context"
+	"errors"
 	"fmt"
 	"net/http"
 	"strconv"
@@ -8,8 +10,14 @@ import (
 	"github.com/go-chi/chi/v5"
 
 	"git.unkin.net/unkin/artifactapi/internal/database"
+	"git.unkin.net/unkin/artifactapi/internal/proxy"
 )
 
+// Evictor drops a remote path from every cache layer.
+type Evictor interface {
+	Evict(ctx context.Context, remoteName, path string) error
+}
+
 type ObjectsHandler struct {
 	db *database.DB
 }
@@ -18,10 +26,13 @@ func NewObjectsHandler(db *database.DB) *ObjectsHandler {
 	return &ObjectsHandler{db: db}
 }
 
-func (h *ObjectsHandler) Routes() chi.Router {
+// Routes lists and evicts objects for remote repos; evictor serves the DELETE.
+func (h *ObjectsHandler) Routes(evictor Evictor) chi.Router {
 	r := chi.NewRouter()
 	r.Get("/", h.list)
-	r.Delete("/*", h.evict)
+	r.Delete("/*", func(w http.ResponseWriter, r *http.Request) {
+		evict(w, r, evictor)
+	})
 	return r
 }
 
@@ -82,11 +93,16 @@ func (h *ObjectsHandler) evictLocal(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusNoContent)
 }
 
-func (h *ObjectsHandler) evict(w http.ResponseWriter, r *http.Request) {
+func evict(w http.ResponseWriter, r *http.Request, evictor Evictor) {
 	remoteName := chi.URLParam(r, "name")
 	path := chi.URLParam(r, "*")
 
-	if err := h.db.DeleteArtifact(r.Context(), remoteName, path); err != nil {
+	if err := evictor.Evict(r.Context(), remoteName, path); err != nil {
+		var proxyErr *proxy.ProxyError
+		if errors.As(err, &proxyErr) {
+			http.Error(w, proxyErr.Message, proxyErr.Status)
+			return
+		}
 		http.Error(w, fmt.Sprintf("evict failed: %v", err), http.StatusInternalServerError)
 		return
 	}

internal/api/v2/objects_evict_test.go

@@ -0,0 +1,59 @@
+package v2
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/go-chi/chi/v5"
+
+	"git.unkin.net/unkin/artifactapi/internal/proxy"
+)
+
+type fakeEvictor struct {
+	remote, path string
+	err          error
+}
+
+func (f *fakeEvictor) Evict(_ context.Context, remote, path string) error {
+	f.remote, f.path = remote, path
+	return f.err
+}
+
+func deleteObject(ev Evictor, path string) int {
+	router := chi.NewRouter()
+	router.Route("/remotes/{name}/objects", func(r chi.Router) {
+		r.Delete("/*", NewObjectsHandler(nil).Routes(ev).ServeHTTP)
+	})
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, httptest.NewRequest("DELETE", "/remotes/epel/objects/"+path, nil))
+	return w.Code
+}
+
+func TestRemoteEvictDelegatesToEvictor(t *testing.T) {
+	for _, path := range []string{"8/Everything/x86_64/repodata/repomd.xml", "8/Everything/x86_64/repodata/*"} {
+		ev := &fakeEvictor{}
+		if code := deleteObject(ev, path); code != 204 || ev.remote != "epel" || ev.path != path {
+			t.Errorf("DELETE %s: code=%d evicted=%q/%q", path, code, ev.remote, ev.path)
+		}
+	}
+}
+
+func TestRemoteEvictMapsErrorStatus(t *testing.T) {
+	for name, tc := range map[string]struct {
+		err  error
+		want int
+	}{
+		"bad wildcard":   {&proxy.ProxyError{Status: http.StatusBadRequest, Message: "wildcard evict must be <dir>/*"}, http.StatusBadRequest},
+		"unknown remote": {&proxy.ProxyError{Status: http.StatusNotFound, Message: "remote not found"}, http.StatusNotFound},
+		"lock busy":      {fmt.Errorf("wrapped: %w", &proxy.ProxyError{Status: http.StatusServiceUnavailable, Message: "retry"}), http.StatusServiceUnavailable},
+		"other error":    {errors.New("db down"), http.StatusInternalServerError},
+	} {
+		if code := deleteObject(&fakeEvictor{err: tc.err}, "x"); code != tc.want {
+			t.Errorf("%s: code = %d, want %d", name, code, tc.want)
+		}
+	}
+}

internal/cache/cache_test.go

@@ -131,3 +131,72 @@ func TestFlushRemote(t *testing.T) {
 		t.Error("expected keys flushed")
 	}
 }
+
+func setPathKeys(t *testing.T, remote string, paths ...string) {
+	t.Helper()
+	ctx := context.Background()
+	for _, p := range paths {
+		if err := testRedis.SetTTL(ctx, remote, p, time.Minute); err != nil {
+			t.Fatal(err)
+		}
+		if err := testRedis.SetETag(ctx, remote, p, `"e"`, time.Minute); err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+func pathKeysExist(t *testing.T, remote, path string) (ttl, etag bool) {
+	t.Helper()
+	ctx := context.Background()
+	ttl, _ = testRedis.CheckTTL(ctx, remote, path)
+	e, _ := testRedis.GetETag(ctx, remote, path)
+	return ttl, e != ""
+}
+
+func TestForgetPath(t *testing.T) {
+	requireRedis(t)
+	const meta = `repo/a*b?[c]\d.xml`
+	setPathKeys(t, "fp", meta, "repo/aXb.xml")
+	setPathKeys(t, "fp-other", meta)
+
+	if err := testRedis.ForgetPath(context.Background(), "fp", meta); err != nil {
+		t.Fatal(err)
+	}
+	if ttl, etag := pathKeysExist(t, "fp", meta); ttl || etag {
+		t.Errorf("forgotten path keys remain: ttl=%v etag=%v", ttl, etag)
+	}
+	for _, k := range [][2]string{{"fp", "repo/aXb.xml"}, {"fp-other", meta}} {
+		if ttl, etag := pathKeysExist(t, k[0], k[1]); !ttl || !etag {
+			t.Errorf("%s:%s lost keys: ttl=%v etag=%v", k[0], k[1], ttl, etag)
+		}
+	}
+}
+
+func TestForgetPrefix(t *testing.T) {
+	requireRedis(t)
+	const prefix = `r*[1]?\/`
+	under := []string{prefix + "repomd.xml", prefix + "sub/x.rpm"}
+	// Each would match the prefix if its glob metacharacters were left unescaped.
+	globMatches := []string{`rX11/repomd.xml`, `r[1]?\/x`, `r*1Z/x`}
+	setPathKeys(t, "fx", append(under, globMatches...)...)
+	setPathKeys(t, "fx-other", under...)
+
+	if err := testRedis.ForgetPrefix(context.Background(), "fx", prefix); err != nil {
+		t.Fatal(err)
+	}
+	for _, p := range under {
+		if ttl, etag := pathKeysExist(t, "fx", p); ttl || etag {
+			t.Errorf("%s keys remain: ttl=%v etag=%v", p, ttl, etag)
+		}
+	}
+	for _, p := range globMatches {
+		if ttl, etag := pathKeysExist(t, "fx", p); !ttl || !etag {
+			t.Errorf("%s outside prefix lost keys: ttl=%v etag=%v", p, ttl, etag)
+		}
+	}
+	for _, p := range under {
+		if ttl, etag := pathKeysExist(t, "fx-other", p); !ttl || !etag {
+			t.Errorf("other remote %s lost keys: ttl=%v etag=%v", p, ttl, etag)
+		}
+	}
+}

internal/cache/redis.go

@@ -3,6 +3,7 @@ package cache
 import (
 	"context"
 	"fmt"
+	"strings"
 	"time"
 
 	"github.com/redis/go-redis/v9"
@@ -115,3 +116,27 @@ func (r *Redis) FlushRemote(ctx context.Context, remote string) error {
 	}
 	return iter.Err()
 }
+
+// ForgetPath drops the freshness and ETag keys of one cached path.
+func (r *Redis) ForgetPath(ctx context.Context, remote, path string) error {
+	return r.client.Del(ctx, fmt.Sprintf("ttl:%s:%s", remote, path), fmt.Sprintf("etag:%s:%s", remote, path)).Err()
+}
+
+// ForgetPrefix drops the freshness and ETag keys of every cached path under prefix.
+func (r *Redis) ForgetPrefix(ctx context.Context, remote, prefix string) error {
+	glob := globEscaper.Replace(remote + ":" + prefix)
+	for _, kind := range []string{"ttl:", "etag:"} {
+		iter := r.client.Scan(ctx, 0, kind+glob+"*", 100).Iterator()
+		for iter.Next(ctx) {
+			if err := r.client.Del(ctx, iter.Val()).Err(); err != nil {
+				return err
+			}
+		}
+		if err := iter.Err(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+var globEscaper = strings.NewReplacer(`\`, `\\`, `*`, `\*`, `?`, `\?`, `[`, `\[`, `]`, `\]`)

internal/database/artifacts.go

@@ -103,6 +103,13 @@ func (db *DB) DeleteArtifact(ctx context.Context, remoteName, path string) error
 	return err
 }
 
+// DeleteArtifactsByPrefix removes every artifact row of a remote whose path
+// starts with prefix.
+func (db *DB) DeleteArtifactsByPrefix(ctx context.Context, remoteName, prefix string) error {
+	_, err := db.Pool.Exec(ctx, `DELETE FROM artifacts WHERE remote_name = $1 AND left(path, length($2)) = $2`, remoteName, prefix)
+	return err
+}
+
 func (db *DB) InsertAccessLog(ctx context.Context, remoteName, path string, cacheHit bool, sizeBytes int64, upstreamMS int, clientIP string) error {
 	_, err := db.Pool.Exec(ctx, `
 		INSERT INTO access_log (remote_name, path, cache_hit, size_bytes, upstream_ms, client_ip)

internal/proxy/engine.go

@@ -16,6 +16,8 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/jackc/pgx/v5"
+
 	"git.unkin.net/unkin/artifactapi/internal/cache"
 	"git.unkin.net/unkin/artifactapi/internal/database"
 	"git.unkin.net/unkin/artifactapi/internal/provider"
@@ -47,6 +49,8 @@ type Engine struct {
 	// mirror strategy to prefer the mirror currently handling the fewest
 	// requests. Per-replica and approximate, which is fine.
 	inflight sync.Map
+	// evictLockWait bounds how long Evict waits on a held fetch lock.
+	evictLockWait time.Duration
 }
 
 func NewEngine(db *database.DB, c *cache.Redis, s *storage.S3) *Engine {
@@ -57,6 +61,8 @@ func NewEngine(db *database.DB, c *cache.Redis, s *storage.S3) *Engine {
 		cas:       storage.NewCAS(s),
 		circuit:   NewCircuitBreaker(c),
 		accessLog: make(chan database.AccessLogEntry, accessLogBufferSize),
+
+		evictLockWait: fetchLockTTL,
 	}
 	go e.runAccessLogWriter()
 	return e
@@ -208,6 +214,71 @@ func (e *Engine) Fetch(ctx context.Context, remote models.Remote, path string, p
 	return result, nil
 }
 
+// Evict drops path from every cache layer (artifact row, index object, Redis
+// freshness and ETag keys) so the next request refetches from upstream. A
+// trailing "/*" evicts every path under that directory.
+func (e *Engine) Evict(ctx context.Context, remoteName, path string) error {
+	prefix, wildcard := strings.CutSuffix(path, "*")
+	if wildcard && !strings.HasSuffix(prefix, "/") {
+		return &ProxyError{Status: http.StatusBadRequest, Message: "wildcard evict must be <dir>/*"}
+	}
+	if _, err := e.db.GetRemote(ctx, remoteName); errors.Is(err, pgx.ErrNoRows) {
+		return &ProxyError{Status: http.StatusNotFound, Message: fmt.Sprintf("remote %q not found", remoteName)}
+	} else if err != nil {
+		return fmt.Errorf("get remote: %w", err)
+	}
+	if !wildcard {
+		if err := e.waitForLock(ctx, remoteName, path); err != nil {
+			return err
+		}
+		defer func() { _ = e.cache.ReleaseLock(context.WithoutCancel(ctx), remoteName, path) }()
+		if err := e.db.DeleteArtifact(ctx, remoteName, path); err != nil {
+			return fmt.Errorf("delete artifact: %w", err)
+		}
+		if err := e.store.Delete(ctx, storage.IndexKey(remoteName, path)); err != nil {
+			return fmt.Errorf("delete index: %w", err)
+		}
+		return e.cache.ForgetPath(ctx, remoteName, path)
+	}
+	// ponytail: no lock for wildcards; a Fetch already in flight under the
+	// prefix can re-cache its path after the evict. Per-path locks over a
+	// directory would close it if that ever matters.
+	if err := e.db.DeleteArtifactsByPrefix(ctx, remoteName, prefix); err != nil {
+		return fmt.Errorf("delete artifacts: %w", err)
+	}
+	if err := e.store.DeletePrefix(ctx, storage.IndexKey(remoteName, prefix)); err != nil {
+		return fmt.Errorf("delete indexes: %w", err)
+	}
+	return e.cache.ForgetPrefix(ctx, remoteName, prefix)
+}
+
+// waitForLock takes the per-path fetch lock so an in-flight Fetch cannot
+// re-set TTL/ETag keys after an evict. It fails with a 503 when the lock
+// cannot be taken within evictLockWait or Redis errors.
+func (e *Engine) waitForLock(ctx context.Context, remoteName, path string) error {
+	deadline := time.Now().Add(e.evictLockWait)
+	for {
+		ok, err := e.cache.AcquireLock(ctx, remoteName, path, fetchLockTTL)
+		if ok {
+			return nil
+		}
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+		if err != nil {
+			return &ProxyError{Status: http.StatusServiceUnavailable, Message: fmt.Sprintf("fetch lock: %v", err)}
+		}
+		if time.Now().After(deadline) {
+			return &ProxyError{Status: http.StatusServiceUnavailable, Message: "fetch in progress, retry evict"}
+		}
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-time.After(50 * time.Millisecond):
+		}
+	}
+}
+
 // HeadResult carries artifact metadata for a HEAD request. There is no body.
 type HeadResult struct {
 	ContentType string

internal/proxy/evict_test.go

@@ -0,0 +1,271 @@
+package proxy
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	_ "git.unkin.net/unkin/artifactapi/internal/provider/rpm"
+	"git.unkin.net/unkin/artifactapi/internal/storage"
+	"git.unkin.net/unkin/artifactapi/pkg/models"
+)
+
+// changingUpstream serves every path with the current revision, as a mirror
+// does after a sync replaces its repodata. It answers 304 to a matching
+// If-None-Match and counts conditional requests.
+func changingUpstream(t *testing.T) (*httptest.Server, *atomic.Value, *atomic.Int32) {
+	t.Helper()
+	var rev atomic.Value
+	var conditional atomic.Int32
+	rev.Store("rev1")
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		v := rev.Load().(string)
+		etag := `"` + v + `"`
+		w.Header().Set("ETag", etag)
+		if inm := r.Header.Get("If-None-Match"); inm != "" {
+			conditional.Add(1)
+			if inm == etag {
+				w.WriteHeader(http.StatusNotModified)
+				return
+			}
+		}
+		_, _ = w.Write([]byte(v + ":" + r.URL.Path))
+	}))
+	t.Cleanup(srv.Close)
+	return srv, &rev, &conditional
+}
+
+func fetchBody(t *testing.T, r models.Remote, path string) string {
+	t.Helper()
+	res, err := testEngine.Fetch(context.Background(), r, path, prov(t, models.PackageRPM))
+	if err != nil {
+		t.Fatalf("fetch %s: %v", path, err)
+	}
+	return readAll(t, res)
+}
+
+func rpmRemote(t *testing.T, name, baseURL string) models.Remote {
+	return seed(t, models.Remote{Name: name, PackageType: models.PackageRPM, RepoType: models.RepoTypeRemote, BaseURL: baseURL, MutableTTL: 7200, CheckMutable: true})
+}
+
+// cached reports which cache layers hold path: artifact row, index object,
+// Redis TTL key, Redis ETag key.
+type cached struct{ row, index, ttl, etag bool }
+
+// Mutable indexes live in the S3 index; immutable blobs get an artifact row.
+var (
+	indexCached = cached{index: true, ttl: true, etag: true}
+	blobCached  = cached{row: true, ttl: true, etag: true}
+)
+
+func layers(t *testing.T, remote, path string) cached {
+	t.Helper()
+	ctx := context.Background()
+	var c cached
+	_, err := testDB.GetArtifact(ctx, remote, path)
+	c.row = err == nil
+	c.index, err = testEngine.store.Exists(ctx, storage.IndexKey(remote, path))
+	if err != nil {
+		t.Fatalf("stat index %s: %v", path, err)
+	}
+	c.ttl, _ = testCache.CheckTTL(ctx, remote, path)
+	etag, _ := testCache.GetETag(ctx, remote, path)
+	c.etag = etag != ""
+	return c
+}
+
+func TestEvictMutableIndexRefetches(t *testing.T) {
+	requireStack(t)
+	srv, rev, conditional := changingUpstream(t)
+	r := rpmRemote(t, "evict-idx", srv.URL)
+	const path = "8/Everything/x86_64/repodata/repomd.xml"
+
+	if got := fetchBody(t, r, path); got != "rev1:/"+path {
+		t.Fatalf("initial fetch = %q", got)
+	}
+	if c := layers(t, r.Name, path); c != indexCached {
+		t.Fatalf("before evict = %+v, want %+v", c, indexCached)
+	}
+	rev.Store("rev2")
+	if got := fetchBody(t, r, path); got != "rev1:/"+path {
+		t.Fatalf("within TTL = %q, want cached rev1", got)
+	}
+	if err := testEngine.Evict(context.Background(), r.Name, path); err != nil {
+		t.Fatalf("evict: %v", err)
+	}
+	if c := layers(t, r.Name, path); c != (cached{}) {
+		t.Fatalf("after evict = %+v, want every layer gone", c)
+	}
+	conditional.Store(0)
+	if got := fetchBody(t, r, path); got != "rev2:/"+path {
+		t.Fatalf("after evict = %q, want rev2", got)
+	}
+	if n := conditional.Load(); n != 0 {
+		t.Errorf("post-evict fetch revalidated with the evicted ETag (%d conditional requests)", n)
+	}
+}
+
+func TestEvictImmutableBlobDropsRow(t *testing.T) {
+	requireStack(t)
+	srv, _, _ := changingUpstream(t)
+	r := rpmRemote(t, "evict-blob", srv.URL)
+	const path = "8/Everything/x86_64/Packages/a/a-1.0-1.el8.x86_64.rpm"
+	fetchBody(t, r, path)
+	if c := layers(t, r.Name, path); c != blobCached {
+		t.Fatalf("before evict = %+v, want %+v", c, blobCached)
+	}
+	if err := testEngine.Evict(context.Background(), r.Name, path); err != nil {
+		t.Fatalf("evict: %v", err)
+	}
+	if c := layers(t, r.Name, path); c != (cached{}) {
+		t.Fatalf("after evict = %+v, want every layer gone", c)
+	}
+}
+
+func TestEvictRejectsNonDirectoryWildcard(t *testing.T) {
+	requireStack(t)
+	srv, _, _ := changingUpstream(t)
+	r := rpmRemote(t, "evict-bare", srv.URL)
+	const path = "8/Everything/x86_64/repodata/repomd.xml"
+	fetchBody(t, r, path)
+
+	for _, bad := range []string{"*", "8*", "8/Every*"} {
+		var pe *ProxyError
+		if err := testEngine.Evict(context.Background(), r.Name, bad); !errors.As(err, &pe) || pe.Status != http.StatusBadRequest {
+			t.Errorf("evict %s = %v, want 400", bad, err)
+		}
+	}
+	if c := layers(t, r.Name, path); c != (indexCached) {
+		t.Errorf("rejected wildcard evicted layers: %+v", c)
+	}
+}
+
+func TestEvictUnknownRemote(t *testing.T) {
+	requireStack(t)
+	var pe *ProxyError
+	if err := testEngine.Evict(context.Background(), "evict-no-such-remote", "a/b"); !errors.As(err, &pe) || pe.Status != http.StatusNotFound {
+		t.Fatalf("evict unknown remote = %v, want 404", err)
+	}
+}
+
+func holdLock(t *testing.T, remote, path string) {
+	t.Helper()
+	ctx := context.Background()
+	if ok, err := testCache.AcquireLock(ctx, remote, path, time.Minute); !ok || err != nil {
+		t.Fatalf("acquire: %v %v", ok, err)
+	}
+	t.Cleanup(func() { _ = testCache.ReleaseLock(ctx, remote, path) })
+}
+
+func TestEvictWaitsForFetchLock(t *testing.T) {
+	requireStack(t)
+	srv, _, _ := changingUpstream(t)
+	r := rpmRemote(t, "evict-lock", srv.URL)
+	ctx := context.Background()
+	const path = "8/Everything/x86_64/repodata/repomd.xml"
+	holdLock(t, r.Name, path)
+	done := make(chan error, 1)
+	go func() { done <- testEngine.Evict(ctx, r.Name, path) }()
+	select {
+	case err := <-done:
+		t.Fatalf("evict returned while fetch lock held: %v", err)
+	case <-time.After(200 * time.Millisecond):
+	}
+	_ = testCache.ReleaseLock(ctx, r.Name, path)
+	if err := <-done; err != nil {
+		t.Fatalf("evict: %v", err)
+	}
+	ok, err := testCache.AcquireLock(ctx, r.Name, path, time.Second)
+	if !ok || err != nil {
+		t.Fatalf("lock still held after evict: %v %v", ok, err)
+	}
+}
+
+func TestEvictCancelledWhileWaitingDeletesNothing(t *testing.T) {
+	requireStack(t)
+	srv, _, _ := changingUpstream(t)
+	r := rpmRemote(t, "evict-cancel", srv.URL)
+	const path = "8/Everything/x86_64/repodata/repomd.xml"
+	fetchBody(t, r, path)
+	holdLock(t, r.Name, path)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	done := make(chan error, 1)
+	go func() { done <- testEngine.Evict(ctx, r.Name, path) }()
+	time.Sleep(100 * time.Millisecond)
+	cancel()
+	select {
+	case err := <-done:
+		if err == nil {
+			t.Fatal("cancelled evict returned nil")
+		}
+	case <-time.After(2 * time.Second):
+		t.Fatal("cancelled evict did not return")
+	}
+	if c := layers(t, r.Name, path); c != (indexCached) {
+		t.Errorf("cancelled evict deleted layers: %+v", c)
+	}
+}
+
+func TestEvictLockTimeoutIs503(t *testing.T) {
+	requireStack(t)
+	srv, _, _ := changingUpstream(t)
+	r := rpmRemote(t, "evict-timeout", srv.URL)
+	const path = "8/Everything/x86_64/repodata/repomd.xml"
+	fetchBody(t, r, path)
+	holdLock(t, r.Name, path)
+	prev := testEngine.evictLockWait
+	testEngine.evictLockWait = 100 * time.Millisecond
+	t.Cleanup(func() { testEngine.evictLockWait = prev })
+
+	var pe *ProxyError
+	if err := testEngine.Evict(context.Background(), r.Name, path); !errors.As(err, &pe) || pe.Status != http.StatusServiceUnavailable {
+		t.Fatalf("evict = %v, want 503", err)
+	}
+	if c := layers(t, r.Name, path); c != (indexCached) {
+		t.Errorf("timed-out evict deleted layers: %+v", c)
+	}
+}
+
+func TestEvictWildcardClearsPrefixOnly(t *testing.T) {
+	requireStack(t)
+	srv, rev, _ := changingUpstream(t)
+	r := rpmRemote(t, "evict-wild", srv.URL)
+	const (
+		repomd = "8/Everything/x86_64/repodata/repomd.xml"
+		rpm    = "8/Everything/x86_64/Packages/a/a-1.0-1.el8.x86_64.rpm"
+		other  = "9/Everything/x86_64/repodata/repomd.xml"
+	)
+	for _, p := range []string{repomd, rpm, other} {
+		fetchBody(t, r, p)
+	}
+	if c := layers(t, r.Name, rpm); c != blobCached {
+		t.Fatalf("%s before evict = %+v, want %+v", rpm, c, blobCached)
+	}
+	rev.Store("rev2")
+
+	if err := testEngine.Evict(context.Background(), r.Name, "8/Everything/x86_64/*"); err != nil {
+		t.Fatalf("evict: %v", err)
+	}
+	for _, p := range []string{repomd, rpm} {
+		if c := layers(t, r.Name, p); c != (cached{}) {
+			t.Errorf("%s after evict = %+v, want every layer gone", p, c)
+		}
+	}
+	if c := layers(t, r.Name, other); c != (indexCached) {
+		t.Errorf("%s outside prefix = %+v, want %+v", other, c, indexCached)
+	}
+	if got := fetchBody(t, r, repomd); got != "rev2:/"+repomd {
+		t.Errorf("index under prefix = %q, want rev2", got)
+	}
+	if got := fetchBody(t, r, rpm); got != "rev2:/"+rpm {
+		t.Errorf("artifact under prefix = %q, want rev2", got)
+	}
+	if got := fetchBody(t, r, other); got != "rev1:/"+other {
+		t.Errorf("path outside prefix = %q, want cached rev1", got)
+	}
+}

internal/server/server.go

@@ -196,8 +196,8 @@ func (s *Server) routes() chi.Router {
 
 		r.Route("/remotes/{name}/objects", func(r chi.Router) {
 			objHandler := v2.NewObjectsHandler(s.db)
-			r.Get("/", objHandler.Routes().ServeHTTP)
-			r.Delete("/*", objHandler.Routes().ServeHTTP)
+			r.Get("/", objHandler.Routes(s.engine).ServeHTTP)
+			r.Delete("/*", objHandler.Routes(s.engine).ServeHTTP)
 		})
 
 		r.Route("/locals/{name}/objects", func(r chi.Router) {

internal/storage/s3.go

@@ -99,6 +99,30 @@ func (s *S3) Stat(ctx context.Context, key string) (*minio.ObjectInfo, error) {
 	return &info, nil
 }
 
+// DeletePrefix removes every object whose key starts with prefix. It lists
+// first so a failed list returns its error instead of deleting nothing.
+func (s *S3) DeletePrefix(ctx context.Context, prefix string) error {
+	var objs []minio.ObjectInfo
+	for obj := range s.client.ListObjects(ctx, s.bucket, minio.ListObjectsOptions{Prefix: prefix, Recursive: true}) {
+		if obj.Err != nil {
+			return obj.Err
+		}
+		objs = append(objs, obj)
+	}
+	ch := make(chan minio.ObjectInfo, len(objs))
+	for _, obj := range objs {
+		ch <- obj
+	}
+	close(ch)
+	var err error
+	for res := range s.client.RemoveObjects(ctx, s.bucket, ch, minio.RemoveObjectsOptions{}) {
+		if res.Err != nil && err == nil {
+			err = res.Err
+		}
+	}
+	return err
+}
+
 // ListStaleObjects returns keys under prefix last modified before cutoff. Used
 // by the GC to reap abandoned staging objects (e.g. cancelled docker pushes).
 func (s *S3) ListStaleObjects(ctx context.Context, prefix string, cutoff time.Time) ([]string, error) {

internal/storage/storage_test.go

@@ -4,11 +4,15 @@ import (
 	"bytes"
 	"context"
 	"io"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"strings"
 	"testing"
 	"time"
 
+	"github.com/minio/minio-go/v7"
+
 	"git.unkin.net/unkin/artifactapi/internal/testsupport"
 )
 
@@ -158,3 +162,26 @@ func TestCASStore(t *testing.T) {
 		t.Errorf("stored content mismatch: %q", got)
 	}
 }
+
+// The fake endpoint fails every list but accepts every delete, as an S3 that
+// tolerates deleting an empty key would.
+func TestDeletePrefixReturnsListError(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodPost {
+			_, _ = io.WriteString(w, `<DeleteResult></DeleteResult>`)
+			return
+		}
+		w.WriteHeader(http.StatusInternalServerError)
+		_, _ = io.WriteString(w, `<Error><Code>InternalError</Code><Message>list failed</Message></Error>`)
+	}))
+	defer srv.Close()
+	client, err := minio.New(strings.TrimPrefix(srv.URL, "http://"), &minio.Options{Region: "us-east-1", MaxRetries: 1})
+	if err != nil {
+		t.Fatal(err)
+	}
+	s := &S3{client: client, bucket: "bucket"}
+	err = s.DeletePrefix(context.Background(), "indexes/r/")
+	if err == nil {
+		t.Fatal("DeletePrefix on a failing list returned nil")
+	}
+}