StorageDriver: GCS: remove support for directory Moves

The Move operation is only used to move uploaded blobs
to their final destination. There is no point in implementing
Move on "folders". Apart from simplifying the code, this also
saves an HTTP request.

Signed-off-by: Arthur Baars <arthur@semmle.com>

docs/storage/driver/gcs/gcs.go

@@ -38,6 +38,8 @@ import (
 	"google.golang.org/cloud"
 	"google.golang.org/cloud/storage"
 
+	"github.com/Sirupsen/logrus"
+
 	ctx "github.com/docker/distribution/context"
 	storagedriver "github.com/docker/distribution/registry/storage/driver"
 	"github.com/docker/distribution/registry/storage/driver/base"
@@ -469,43 +471,8 @@ func (d *driver) List(context ctx.Context, path string) ([]string, error) {
 // Move moves an object stored at sourcePath to destPath, removing the
 // original object.
 func (d *driver) Move(context ctx.Context, sourcePath string, destPath string) error {
-	prefix := d.pathToDirKey(sourcePath)
 	gcsContext := d.context(context)
-	keys, err := d.listAll(gcsContext, prefix)
-	if err != nil {
-		return err
-	}
-	if len(keys) > 0 {
-		destPrefix := d.pathToDirKey(destPath)
-		copies := make([]string, 0, len(keys))
-		sort.Strings(keys)
-		var err error
-		for _, key := range keys {
-			dest := destPrefix + key[len(prefix):]
-			_, err = storageCopyObject(gcsContext, d.bucket, key, d.bucket, dest, nil)
-			if err == nil {
-				copies = append(copies, dest)
-			} else {
-				break
-			}
-		}
-		// if an error occurred, attempt to cleanup the copies made
-		if err != nil {
-			for i := len(copies) - 1; i >= 0; i-- {
-				_ = storageDeleteObject(gcsContext, d.bucket, copies[i])
-			}
-			return err
-		}
-		// delete originals
-		for i := len(keys) - 1; i >= 0; i-- {
-			err2 := storageDeleteObject(gcsContext, d.bucket, keys[i])
-			if err2 != nil {
-				err = err2
-			}
-		}
-		return err
-	}
-	_, err = storageCopyObject(gcsContext, d.bucket, d.pathToKey(sourcePath), d.bucket, d.pathToKey(destPath), nil)
+	_, err := storageCopyObject(gcsContext, d.bucket, d.pathToKey(sourcePath), d.bucket, d.pathToKey(destPath), nil)
 	if err != nil {
 		if status := err.(*googleapi.Error); status != nil {
 			if status.Code == http.StatusNotFound {
@@ -514,7 +481,13 @@ func (d *driver) Move(context ctx.Context, sourcePath string, destPath string) e
 		}
 		return err
 	}
-	return storageDeleteObject(gcsContext, d.bucket, d.pathToKey(sourcePath))
+	err = storageDeleteObject(gcsContext, d.bucket, d.pathToKey(sourcePath))
+	// if deleting the file fails, log the error, but do not fail; the file was succesfully copied,
+	// and the original should eventually be cleaned when purging the uploads folder.
+	if err != nil {
+		logrus.Infof("error deleting file: %v due to %v", sourcePath, err)
+	}
+	return nil
 }
 
 // listAll recursively lists all names of objects stored at "prefix" and its subpaths.
@@ -530,8 +503,8 @@ func (d *driver) listAll(context context.Context, prefix string) ([]string, erro
 		}
 		for _, obj := range objects.Results {
 			// GCS does not guarantee strong consistency between
-			// DELETE and LIST operationsCheck that the object is not deleted,
-			// so filter out any objects with a non-zero time-deleted
+			// DELETE and LIST operations. Check that the object is not deleted,
+			// and filter out any objects with a non-zero time-deleted
 			if obj.Deleted.IsZero() {
 				list = append(list, obj.Name)
 			}

docs/storage/driver/gcs/gcs_test.go

@@ -175,3 +175,40 @@ func TestEmptyRootList(t *testing.T) {
 		}
 	}
 }
+
+// TestMoveDirectory checks that moving a directory returns an error.
+func TestMoveDirectory(t *testing.T) {
+	if skipGCS() != "" {
+		t.Skip(skipGCS())
+	}
+
+	validRoot, err := ioutil.TempDir("", "driver-")
+	if err != nil {
+		t.Fatalf("unexpected error creating temporary directory: %v", err)
+	}
+	defer os.Remove(validRoot)
+
+	driver, err := gcsDriverConstructor(validRoot)
+	if err != nil {
+		t.Fatalf("unexpected error creating rooted driver: %v", err)
+	}
+
+	ctx := ctx.Background()
+	contents := []byte("contents")
+	// Create a regular file.
+	err = driver.PutContent(ctx, "/parent/dir/foo", contents)
+	if err != nil {
+		t.Fatalf("unexpected error creating content: %v", err)
+	}
+	defer func() {
+		err := driver.Delete(ctx, "/parent")
+		if err != nil {
+			t.Fatalf("failed to remove /parent due to %v\n", err)
+		}
+	}()
+
+	err = driver.Move(ctx, "/parent/dir", "/parent/other")
+	if err == nil {
+		t.Fatalf("Moving directory /parent/dir /parent/other should have return a non-nil error\n")
+	}
+}