Fix signature handling with GC.

If a schema 1 manifest is uploaded with the `disablesignaturestore` option set
to true, then no signatures will exist.  Handle this case.

If a schema 1 manifest is pushed, deleted, garbage collected and pushed again, the
repository will contain signature links from the first version, but the blobs will
not exist.  Disable the signature store in the garbage-collect command so
signatures are not fetched.

Signed-off-by: Richard Scothern <richard.scothern@docker.com>

docs/garbagecollect.go

@@ -13,20 +13,18 @@ import (
 	"github.com/docker/distribution/registry/storage"
 	"github.com/docker/distribution/registry/storage/driver"
 	"github.com/docker/distribution/registry/storage/driver/factory"
+	"github.com/docker/libtrust"
 	"github.com/spf13/cobra"
 )
 
-func emit(ctx context.Context, s string) {
+func emit(format string, a ...interface{}) {
 	if dryRun {
-		context.GetLogger(ctx).Infof("gc: %s", s)
+		fmt.Printf(format, a...)
+		fmt.Println("")
 	}
 }
 
-func markAndSweep(ctx context.Context, storageDriver driver.StorageDriver) error {
-	registry, err := storage.NewRegistry(ctx, storageDriver)
-	if err != nil {
-		return fmt.Errorf("failed to construct registry: %v", err)
-	}
+func markAndSweep(ctx context.Context, storageDriver driver.StorageDriver, registry distribution.Namespace) error {
 
 	repositoryEnumerator, ok := registry.(distribution.RepositoryEnumerator)
 	if !ok {
@@ -35,8 +33,8 @@ func markAndSweep(ctx context.Context, storageDriver driver.StorageDriver) error
 
 	// mark
 	markSet := make(map[digest.Digest]struct{})
-	err = repositoryEnumerator.Enumerate(ctx, func(repoName string) error {
-		emit(ctx, fmt.Sprint(repoName))
+	err := repositoryEnumerator.Enumerate(ctx, func(repoName string) error {
+		emit(repoName)
 
 		var err error
 		named, err := reference.ParseNamed(repoName)
@@ -59,8 +57,8 @@ func markAndSweep(ctx context.Context, storageDriver driver.StorageDriver) error
 		}
 
 		err = manifestEnumerator.Enumerate(ctx, func(dgst digest.Digest) error {
-			// Mark the manifest's blo
-			emit(ctx, fmt.Sprintf("%s: adding manifest %s ", repoName, dgst))
+			// Mark the manifest's blob
+			emit("%s: marking manifest %s ", repoName, dgst)
 			markSet[dgst] = struct{}{}
 
 			manifest, err := manifestService.Get(ctx, dgst)
@@ -71,7 +69,7 @@ func markAndSweep(ctx context.Context, storageDriver driver.StorageDriver) error
 			descriptors := manifest.References()
 			for _, descriptor := range descriptors {
 				markSet[descriptor.Digest] = struct{}{}
-				emit(ctx, fmt.Sprintf("%s: marking blob %v", repoName, descriptor))
+				emit("%s: marking blob %s", repoName, descriptor.Digest)
 			}
 
 			switch manifest.(type) {
@@ -85,13 +83,13 @@ func markAndSweep(ctx context.Context, storageDriver driver.StorageDriver) error
 					return fmt.Errorf("failed to get signatures for signed manifest: %v", err)
 				}
 				for _, signatureDigest := range signatures {
-					emit(ctx, fmt.Sprintf("%s: marking signature %s", repoName, signatureDigest))
+					emit("%s: marking signature %s", repoName, signatureDigest)
 					markSet[signatureDigest] = struct{}{}
 				}
 				break
 			case *schema2.DeserializedManifest:
 				config := manifest.(*schema2.DeserializedManifest).Config
-				emit(ctx, fmt.Sprintf("%s: marking configuration %s", repoName, config.Digest))
+				emit("%s: marking configuration %s", repoName, config.Digest)
 				markSet[config.Digest] = struct{}{}
 				break
 			}
@@ -120,11 +118,12 @@ func markAndSweep(ctx context.Context, storageDriver driver.StorageDriver) error
 		return fmt.Errorf("error enumerating blobs: %v", err)
 	}
 
+	emit("\n%d blobs marked, %d blobs eligible for deletion", len(markSet), len(deleteSet))
 	// Construct vacuum
 	vacuum := storage.NewVacuum(ctx, storageDriver)
 	for dgst := range deleteSet {
 		if dryRun {
-			emit(ctx, fmt.Sprintf("deleting %s", dgst))
+			emit("deleting %s", dgst)
 			continue
 		}
 		err = vacuum.RemoveBlob(string(dgst))
@@ -168,7 +167,19 @@ var GCCmd = &cobra.Command{
 			os.Exit(1)
 		}
 
-		err = markAndSweep(ctx, driver)
+		k, err := libtrust.GenerateECP256PrivateKey()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s", err)
+			os.Exit(1)
+		}
+
+		registry, err := storage.NewRegistry(ctx, driver, storage.DisableSchema1Signatures, storage.Schema1SigningKey(k))
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "failed to construct registry: %v", err)
+			os.Exit(1)
+		}
+
+		err = markAndSweep(ctx, driver, registry)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "failed to garbage collect: %v", err)
 			os.Exit(1)

docs/garbagecollect_test.go

@@ -161,7 +161,7 @@ func TestNoDeletionNoEffect(t *testing.T) {
 	}
 
 	// Run GC
-	err = markAndSweep(context.Background(), inmemoryDriver)
+	err = markAndSweep(context.Background(), inmemoryDriver, registry)
 	if err != nil {
 		t.Fatalf("Failed mark and sweep: %v", err)
 	}
@@ -193,7 +193,7 @@ func TestDeletionHasEffect(t *testing.T) {
 	manifests.Delete(ctx, image3.manifestDigest)
 
 	// Run GC
-	err = markAndSweep(context.Background(), inmemoryDriver)
+	err = markAndSweep(context.Background(), inmemoryDriver, registry)
 	if err != nil {
 		t.Fatalf("Failed mark and sweep: %v", err)
 	}
@@ -327,7 +327,7 @@ func TestOrphanBlobDeleted(t *testing.T) {
 	uploadRandomSchema2Image(t, repo)
 
 	// Run GC
-	err = markAndSweep(context.Background(), inmemoryDriver)
+	err = markAndSweep(context.Background(), inmemoryDriver, registry)
 	if err != nil {
 		t.Fatalf("Failed mark and sweep: %v", err)
 	}

docs/storage/manifeststore.go

@@ -12,6 +12,7 @@ import (
 	"github.com/docker/distribution/manifest/manifestlist"
 	"github.com/docker/distribution/manifest/schema1"
 	"github.com/docker/distribution/manifest/schema2"
+	"github.com/docker/distribution/registry/storage/driver"
 )
 
 // A ManifestHandler gets and puts manifests of a particular type.
@@ -161,13 +162,20 @@ func (ms *manifestStore) GetSignatures(ctx context.Context, manifestDigest diges
 		return nil, err
 	}
 
+	var digests []digest.Digest
 	alg := string(digest.SHA256)
 	signaturePaths, err := ms.blobStore.driver.List(ctx, path.Join(signaturesPath, alg))
-	if err != nil {
+
+	switch err.(type) {
+	case nil:
+		break
+	case driver.PathNotFoundError:
+		// Manifest may have been pushed with signature store disabled
+		return digests, nil
+	default:
 		return nil, err
 	}
 
-	var digests []digest.Digest
 	for _, sigPath := range signaturePaths {
 		sigdigest, err := digest.ParseDigest(alg + ":" + path.Base(sigPath))
 		if err != nil {