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)
+		}
+	}
+}