server: skip blob verification for already verified blobs

server/download.go

@@ -340,17 +340,17 @@ type downloadOpts struct {
 }
 
 // downloadBlob downloads a blob from the registry and stores it in the blobs directory
-func downloadBlob(ctx context.Context, opts downloadOpts) error {
+func downloadBlob(ctx context.Context, opts downloadOpts) (cacheHit bool, _ error) {
 	fp, err := GetBlobsPath(opts.digest)
 	if err != nil {
-		return err
+		return false, err
 	}
 
 	fi, err := os.Stat(fp)
 	switch {
 	case errors.Is(err, os.ErrNotExist):
 	case err != nil:
-		return err
+		return false, err
 	default:
 		opts.fn(api.ProgressResponse{
 			Status:    fmt.Sprintf("pulling %s", opts.digest[7:19]),
@@ -359,7 +359,7 @@ func downloadBlob(ctx context.Context, opts downloadOpts) error {
 			Completed: fi.Size(),
 		})
 
-		return nil
+		return true, nil
 	}
 
 	data, ok := blobDownloadManager.LoadOrStore(opts.digest, &blobDownload{Name: fp, Digest: opts.digest})
@@ -369,12 +369,12 @@ func downloadBlob(ctx context.Context, opts downloadOpts) error {
 		requestURL = requestURL.JoinPath("v2", opts.mp.GetNamespaceRepository(), "blobs", opts.digest)
 		if err := download.Prepare(ctx, requestURL, opts.regOpts); err != nil {
 			blobDownloadManager.Delete(opts.digest)
-			return err
+			return false, err
 		}
 
 		//nolint:contextcheck
 		go download.Run(context.Background(), requestURL, opts.regOpts)
 	}
 
-	return download.Wait(ctx, opts.fn)
+	return false, download.Wait(ctx, opts.fn)
 }

server/images.go

@@ -853,23 +853,27 @@ func PullModel(ctx context.Context, name string, regOpts *registryOptions, fn fu
 	layers = append(layers, manifest.Layers...)
 	layers = append(layers, manifest.Config)
 
+	skipVerify := make(map[string]bool)
 	for _, layer := range layers {
-		if err := downloadBlob(
-			ctx,
-			downloadOpts{
-				mp:      mp,
-				digest:  layer.Digest,
-				regOpts: regOpts,
-				fn:      fn,
-			}); err != nil {
+		cacheHit, err := downloadBlob(ctx, downloadOpts{
+			mp:      mp,
+			digest:  layer.Digest,
+			regOpts: regOpts,
+			fn:      fn,
+		})
+		if err != nil {
 			return err
 		}
+		skipVerify[layer.Digest] = cacheHit
 		delete(deleteMap, layer.Digest)
 	}
 	delete(deleteMap, manifest.Config.Digest)
 
 	fn(api.ProgressResponse{Status: "verifying sha256 digest"})
 	for _, layer := range layers {
+		if skipVerify[layer.Digest] {
+			continue
+		}
 		if err := verifyBlob(layer.Digest); err != nil {
 			if errors.Is(err, errDigestMismatch) {
 				// something went wrong, delete the blob