Open() is called in the pullthrough code path and needs retry

Added tests

Author: smarterclayton

pkg/image/importer/client.go

@@ -407,3 +407,13 @@ func (r retryBlobStore) ServeBlob(ctx context.Context, w http.ResponseWriter, re
 		}
 	}
 }
+
+func (r retryBlobStore) Open(ctx context.Context, dgst digest.Digest) (distribution.ReadSeekCloser, error) {
+	for {
+		if rsc, err := r.BlobStore.Open(ctx, dgst); r.repo.shouldRetry(err) {
+			continue
+		} else {
+			return rsc, err
+		}
+	}
+}

pkg/image/importer/client_test.go

@@ -75,7 +75,7 @@ func (r *mockRepository) GetByTag(tag string, options ...distribution.ManifestSe
 type mockBlobStore struct {
 	distribution.BlobStore
 
-	statErr, serveErr error
+	statErr, serveErr, openErr error
 }
 
 func (r *mockBlobStore) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
@@ -86,6 +86,10 @@ func (r *mockBlobStore) ServeBlob(ctx context.Context, w http.ResponseWriter, re
 	return r.serveErr
 }
 
+func (r *mockBlobStore) Open(ctx context.Context, dgst digest.Digest) (distribution.ReadSeekCloser, error) {
+	return nil, r.openErr
+}
+
 func TestSchema1ToImage(t *testing.T) {
 	m := &schema1.SignedManifest{}
 	if err := json.Unmarshal([]byte(etcdManifest), m); err != nil {
@@ -284,6 +288,7 @@ func TestRetryFailure(t *testing.T) {
 		blobs: &mockBlobStore{
 			serveErr: errcode.ErrorCodeUnauthorized,
 			statErr:  errcode.ErrorCodeUnauthorized,
+			openErr:  errcode.ErrorCodeUnauthorized,
 		},
 	}
 	r = NewRetryRepository(repo, 4, 0).(*retryRepository)
@@ -326,4 +331,8 @@ func TestRetryFailure(t *testing.T) {
 	if err := b.ServeBlob(nil, nil, nil, digest.Digest("foo")); err != repo.getErr || r.retries != 0 {
 		t.Fatalf("unexpected: %v %v %#v", m, err, r)
 	}
+	r.retries = 2
+	if _, err := b.Open(nil, digest.Digest("foo")); err != repo.getErr || r.retries != 0 {
+		t.Fatalf("unexpected: %v %v %#v", m, err, r)
+	}
 }