One corrupt manifest should not wedge model operations (#7515)

One potential failure mode is an empty file which bubbles up as an EOF error,
leading to all pulls and listing operations failing.  Instead, continue and
warn about the corrupt manifest.  This also allows re-pulling the corrupt
manifest to repair the system.

server/images.go

@@ -690,7 +690,8 @@ func CopyModel(src, dst model.Name) error {
 }
 
 func deleteUnusedLayers(deleteMap map[string]struct{}) error {
-	manifests, err := Manifests()
+	// Ignore corrupt manifests to avoid blocking deletion of layers that are freshly orphaned
+	manifests, err := Manifests(true)
 	if err != nil {
 		return err
 	}
@@ -853,8 +854,8 @@ func PullModel(ctx context.Context, name string, regOpts *registryOptions, fn fu
 	manifest, _, err := GetManifest(mp)
 	if errors.Is(err, os.ErrNotExist) {
 		// noop
-	} else if err != nil && !errors.Is(err, os.ErrNotExist) {
+	} else if err != nil {
-		return err
+		slog.Warn("pulling model with bad existing manifest", "name", name, "error", err)
 	} else {
 		for _, l := range manifest.Layers {
 			deleteMap[l.Digest] = struct{}{}

server/layer.go

@@ -106,7 +106,8 @@ func (l *Layer) Remove() error {
 		return nil
 	}
 
-	ms, err := Manifests()
+	// Ignore corrupt manifests to avoid blocking deletion of layers that are freshly orphaned
+	ms, err := Manifests(true)
 	if err != nil {
 		return err
 	}

server/manifest.go

@@ -123,7 +123,7 @@ func WriteManifest(name model.Name, config Layer, layers []Layer) error {
 	return json.NewEncoder(f).Encode(m)
 }
 
-func Manifests() (map[model.Name]*Manifest, error) {
+func Manifests(continueOnError bool) (map[model.Name]*Manifest, error) {
 	manifests, err := GetManifestPath()
 	if err != nil {
 		return nil, err
@@ -145,22 +145,29 @@ func Manifests() (map[model.Name]*Manifest, error) {
 		if !fi.IsDir() {
 			rel, err := filepath.Rel(manifests, match)
 			if err != nil {
+				if !continueOnError {
+					return nil, fmt.Errorf("%s %w", match, err)
+				}
 				slog.Warn("bad filepath", "path", match, "error", err)
 				continue
 			}
 
 			n := model.ParseNameFromFilepath(rel)
 			if !n.IsValid() {
+				if !continueOnError {
+					return nil, fmt.Errorf("%s %w", rel, err)
+				}
 				slog.Warn("bad manifest name", "path", rel)
 				continue
 			}
 
 			m, err := ParseNamedManifest(n)
-			if syntax := &(json.SyntaxError{}); errors.As(err, &syntax) {
+			if err != nil {
+				if !continueOnError {
+					return nil, fmt.Errorf("%s %w", n, err)
+				}
 				slog.Warn("bad manifest", "name", n, "error", err)
 				continue
-			} else if err != nil {
-				return nil, fmt.Errorf("%s: %w", n, err)
 			}
 
 			ms[n] = m

server/manifest_test.go

@@ -112,7 +112,7 @@ func TestManifests(t *testing.T) {
 				createManifest(t, d, p)
 			}
 
-			ms, err := Manifests()
+			ms, err := Manifests(true)
 			if err != nil {
 				t.Fatal(err)
 			}

server/routes.go

@@ -622,7 +622,7 @@ func (s *Server) PushHandler(c *gin.Context) {
 }
 
 func checkNameExists(name model.Name) error {
-	names, err := Manifests()
+	names, err := Manifests(true)
 	if err != nil {
 		return err
 	}
@@ -894,7 +894,7 @@ func getKVData(digest string, verbose bool) (llm.KV, error) {
 }
 
 func (s *Server) ListHandler(c *gin.Context) {
-	ms, err := Manifests()
+	ms, err := Manifests(true)
 	if err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
 		return
@@ -1211,6 +1211,9 @@ func Serve(ln net.Listener) error {
 	}
 
 	if !envconfig.NoPrune() {
+		if _, err := Manifests(false); err != nil {
+			slog.Warn("corrupt manifests detected, skipping prune operation.  Re-pull or delete to clear", "error", err)
+		} else {
 			// clean up unused layers and manifests
 			if err := PruneLayers(); err != nil {
 				return err
@@ -1225,6 +1228,7 @@ func Serve(ln net.Listener) error {
 				return err
 			}
 		}
+	}
 
 	ctx, done := context.WithCancel(context.Background())
 	schedCtx, schedDone := context.WithCancel(ctx)