[PRFix modify fetchReference]

Signed-off-by: Zoey Li <[email protected]>

cmd/oras/blob/fetch.go

@@ -44,26 +44,26 @@ type fetchBlobOptions struct {
 func fetchCmd() *cobra.Command {
 	var opts fetchBlobOptions
 	cmd := &cobra.Command{
-		Use:   "fetch <name@digest> [flags]",
+		Use:   "fetch [flags] <name@digest>",
 		Short: "[Preview] Fetch a blob from a remote registry",
 		Long: `[Preview] Fetch a blob from a remote registry
 
 ** This command is in preview and under development. **
 
 Example - Fetch the blob and save it to a local file:
-  oras blob fetch localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5 --output blob.tar.gz
+  oras blob fetch --output blob.tar.gz localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5
 
 Example - Fetch the blob and stdout the raw blob content:
-  oras blob fetch localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5 --output -
+  oras blob fetch --output - localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5
 
 Example - Fetch the blob and stdout the descriptor of a blob:
-  oras blob fetch localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5 --descriptor
+  oras blob fetch --descriptor localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5
 
-Example - Fetch the blob and save it to a local file and stdout the descriptor:
-  oras blob fetch localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5 --output blob.tar.gz --descriptor
+Example - Fetch the blob, save it to a local file and stdout the descriptor:
+  oras blob fetch --output blob.tar.gz --descriptor localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5
 
 Example - Fetch blob from the insecure registry:
-  oras blob fetch localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5 --insecure
+  oras blob fetch --insecure localhost:5000/hello@sha256:9a201d228ebd966211f7d1131be19f152be428bd373a92071c71d8deaf83b3e5
 `,
 		Args: cobra.ExactArgs(1),
 		PreRunE: func(cmd *cobra.Command, args []string) error {

internal/cache/target.go

@@ -117,36 +117,37 @@ type referenceTarget struct {
 	registry.ReferenceFetcher
 }
 
-// FetchReference fetches the content identified by the reference from the cache
-// if exists, otherwise fetches the content from the remote and then cache the
-// fetched content.
+// FetchReference fetches the content identified by the reference from the
+// remote and cache the fetched content.
 // Cached content will only be read via Fetch, FetchReference will always fetch
 // From origin.
 func (t *referenceTarget) FetchReference(ctx context.Context, reference string) (ocispec.Descriptor, io.ReadCloser, error) {
-	desc, err := t.Resolve(ctx, reference)
+	target, rc, err := t.ReferenceFetcher.FetchReference(ctx, reference)
 	if err != nil {
 		return ocispec.Descriptor{}, nil, err
 	}
 
 	// skip caching if the content already exists in cache
-	exists, err := t.cache.Exists(ctx, desc)
+	exists, err := t.cache.Exists(ctx, target)
 	if err != nil {
 		return ocispec.Descriptor{}, nil, err
 	}
 	if exists {
+		err = rc.Close()
+		if err != nil {
+			return ocispec.Descriptor{}, nil, err
+		}
+
 		// get rc from the cache
-		rc, err := t.cache.Fetch(ctx, desc)
+		rc, err = t.cache.Fetch(ctx, target)
 		if err != nil {
 			return ocispec.Descriptor{}, nil, err
 		}
-		return desc, rc, nil
-	}
 
-	desc, rc, err := t.ReferenceFetcher.FetchReference(ctx, reference)
-	if err != nil {
-		return ocispec.Descriptor{}, nil, err
+		// no need to do tee'd push
+		return target, rc, nil
 	}
 
 	// Fetch from origin with caching
-	return desc, t.cacheReadCloser(ctx, rc, desc), nil
+	return target, t.cacheReadCloser(ctx, rc, target), nil
 }

internal/cache/target_test.go

@@ -178,14 +178,6 @@ func TestProxy_fetchReference(t *testing.T) {
 			w.Write(blob)
 			atomic.AddInt64(&successCount, 1)
 			return
-		} else if r.Method == http.MethodHead &&
-			(r.URL.Path == fmt.Sprintf("/v2/%s/manifests/%s", repoName, tagName) ||
-				r.URL.Path == fmt.Sprintf("/v2/%s/manifests/%s", repoName, digest)) {
-			w.Header().Set("Content-Type", mediaType)
-			w.Header().Set("Docker-Content-Digest", digest.String())
-			w.Header().Set("Content-Length", strconv.Itoa(len([]byte(blob))))
-			atomic.AddInt64(&successCount, 1)
-			return
 		}
 		t.Errorf("unexpected access: %s %s", r.Method, r.URL)
 		w.WriteHeader(http.StatusBadRequest)
@@ -223,21 +215,6 @@ func TestProxy_fetchReference(t *testing.T) {
 	if !bytes.Equal(got, blob) {
 		t.Errorf("ReferenceTarget.Fetch() = %v, want %v", got, blob)
 	}
-	if wantRequestCount += 2; requestCount != wantRequestCount {
-		t.Errorf("unexpected number of requests: %d, want %d", requestCount, wantRequestCount)
-	}
-	if wantSuccessCount += 2; successCount != wantSuccessCount {
-		t.Errorf("unexpected number of successful requests: %d, want %d", successCount, wantSuccessCount)
-	}
-
-	// second fetch reference, should get the content from the cache
-	gotDesc, _, err = p.(registry.ReferenceFetcher).FetchReference(ctx, repo.Reference.Reference)
-	if err != nil {
-		t.Fatal("ReferenceTarget.FetchReference() error =", err)
-	}
-	if !reflect.DeepEqual(gotDesc, desc) {
-		t.Fatalf("ReferenceTarget.FetchReference() got %v, want %v", gotDesc, desc)
-	}
 	if wantRequestCount++; requestCount != wantRequestCount {
 		t.Errorf("unexpected number of requests: %d, want %d", requestCount, wantRequestCount)
 	}