registry/storage/driver/azure: fix storage path to use leading slash

this keeps backwards compatibility with pre-v3 registries.

registry/storage/driver/azure/azure.go

@@ -410,13 +410,9 @@ func (d *driver) listBlobs(ctx context.Context, virtPath string) ([]string, erro
 	// This is to cover for the cases when the rootDirectory of the driver is either "" or "/".
 	// In those cases, there is no root prefix to replace and we must actually add a "/" to all
 	// results in order to keep them as valid paths as recognized by storagedriver.PathRegexp
-	prefix := ""
-	if blobPrefix == "" {
-		prefix = "/"
-	}
+	prefix := "/"
 
 	out := []string{}
-
 	listPrefix := d.blobName(virtPath)
 	pager := d.client.NewListBlobsFlatPager(&container.ListBlobsFlatOptions{
 		Prefix: &listPrefix,
@@ -432,6 +428,7 @@ func (d *driver) listBlobs(ctx context.Context, virtPath string) ([]string, erro
 			}
 			name := *blob.Name
 			out = append(out, strings.Replace(name, blobPrefix, prefix, 1))
+
 		}
 	}
 
@@ -446,7 +443,9 @@ func (d *driver) blobName(path string) string {
 		return path
 	}
 
-	return strings.TrimLeft(strings.TrimRight(d.rootDirectory, "/")+path, "/")
+	trimmedRoot := strings.TrimRight(d.rootDirectory, "/")
+	trimmedPath := strings.TrimLeft(path, "/")
+	return trimmedRoot + "/" + trimmedPath
 }
 
 func is404(err error) bool {

registry/storage/driver/azure/azure_test.go

@@ -91,6 +91,64 @@ func randStringRunes(n int) string {
 	return string(b)
 }
 
+func writeBlob(ctx context.Context, driver storagedriver.StorageDriver, contents, path string, append_ bool) error {
+	writer, err := driver.Writer(ctx, path, append_)
+	if err != nil {
+		return fmt.Errorf("unexpected error from driver.Writer: %v", err)
+	}
+	_, err = writer.Write([]byte(contents))
+	if err != nil {
+		return fmt.Errorf("writer.Write: unexpected error: %v", err)
+	}
+
+	err = writer.Commit()
+	if err != nil {
+		return fmt.Errorf("writer.Commit: unexpected error: %v", err)
+	}
+	err = writer.Close()
+	if err != nil {
+		return fmt.Errorf("writer.Close: unexpected error: %v", err)
+	}
+	return nil
+}
+
+func TestListBlobs(t *testing.T) {
+	driver, err := azureDriverConstructor()
+	if err != nil {
+		t.Fatalf("unexpected error creating azure driver: %v", err)
+	}
+
+	contents := randStringRunes(4 * 1024 * 1024)
+	path := "/file"
+	ctx := context.Background()
+
+	defer driver.Delete(ctx, path)
+	if err := writeBlob(ctx, driver, contents, path, false); err != nil {
+		t.Fatal(err)
+	}
+
+	blobNames, err := driver.List(ctx, "/")
+	if err != nil {
+		t.Fatalf("driver.List: unexpected error: %v", err)
+	}
+
+	if len(blobNames) == 0 {
+		t.Fatalf("blob %q was not listed! driver.List returned 0 blobs!", path)
+	}
+
+	found := false
+	for _, blobName := range blobNames {
+		if blobName == path {
+			found = true
+			break
+		}
+		fmt.Println("TestListBlobs blobName", blobName, "did not match path", path)
+	}
+	if !found {
+		t.Fatalf("blob %q was not listed!", path)
+	}
+}
+
 func TestCommitAfterMove(t *testing.T) {
 	driver, err := azureDriverConstructor()
 	if err != nil {