Replace git cloner with go getter to support various target

api/loader/fileloader.go

@@ -164,30 +164,49 @@ func (fl *fileLoader) New(path string) (ifc.Loader, error) {
 	if path == "" {
 		return nil, fmt.Errorf("new root cannot be empty")
 	}
-	repoSpec, err := git.NewRepoSpecFromUrl(path)
-	if err == nil {
-		// Treat this as git repo clone request.
+
+	root, errD := func() (filesys.ConfirmedDir, error) {
+		if filepath.IsAbs(path) {
+			return "", fmt.Errorf("new root '%s' cannot be absolute", path)
+		}
+		root, err := demandDirectoryRoot(fl.fSys, fl.root.Join(path))
+		if err != nil {
+			return "", err
+		}
+		if err := fl.errIfGitContainmentViolation(root); err != nil {
+			return "", err
+		}
+		if err := fl.errIfArgEqualOrHigher(root); err != nil {
+			return "", err
+		}
+		return root, nil
+	}()
+
+	if errD == nil {
+		return newLoaderAtConfirmedDir(
+			fl.loadRestrictor, root, fl.fSys, fl, fl.cloner), nil
+	}
+
+	ldr, errL := func() (ifc.Loader, error) {
+		repoSpec, err := git.NewRepoSpecFromUrl(path)
+		if err != nil {
+			return nil, err
+		}
 		if err := fl.errIfRepoCycle(repoSpec); err != nil {
 			return nil, err
 		}
-		return newLoaderAtGitClone(
-			repoSpec, fl.fSys, fl, fl.cloner)
+		ldr, err := newLoaderAtGitClone(repoSpec, fl.fSys, fl, fl.cloner)
+
+		if err != nil {
+			return nil, fmt.Errorf("Error create loader: %s", err)
+		}
+		return ldr, nil
+	}()
+
+	if errL == nil {
+		return ldr, nil
 	}
-	if filepath.IsAbs(path) {
-		return nil, fmt.Errorf("new root '%s' cannot be absolute", path)
-	}
-	root, err := demandDirectoryRoot(fl.fSys, fl.root.Join(path))
-	if err != nil {
-		return nil, err
-	}
-	if err := fl.errIfGitContainmentViolation(root); err != nil {
-		return nil, err
-	}
-	if err := fl.errIfArgEqualOrHigher(root); err != nil {
-		return nil, err
-	}
-	return newLoaderAtConfirmedDir(
-		fl.loadRestrictor, root, fl.fSys, fl, fl.cloner), nil
+	return nil, fmt.Errorf("cannot load at directory %q nor load at git clone %q", errD, errL)
 }
 
 // newLoaderAtGitClone returns a new Loader pinned to a temporary