src: better errors when custom runtime not found

client_test.go

@@ -215,6 +215,31 @@ func TestRuntimeNotFound(t *testing.T) {
 	}
 }
 
+// TODO: TestRuntimeNotFoundCustom ensures that the correct error is returned
+// when the requested runtime is not found in a given custom repository
+func TestRuntimeNotFoundCustom(t *testing.T) {
+	root := "testdata/example.com/testRuntimeNotFoundCustom"
+	if err := os.MkdirAll(root, 0700); err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(root)
+
+	// Create a new client with path to the extensible templates
+	client := bosonFunc.New(
+		bosonFunc.WithTemplates("testdata/repositories"),
+		bosonFunc.WithRegistry(TestRegistry))
+
+	// Create a Function specifying a runtime, 'python' that does not exist
+	// in the custom (testdata) repository but does in the embedded.
+	f := bosonFunc.Function{Root: root, Runtime: "python", Trigger: "customProvider/event"}
+
+	// creating should error as runtime not found
+	err := client.New(context.Background(), f)
+	if !errors.Is(err, bosonFunc.ErrRuntimeNotFound) {
+		t.Fatal(err)
+	}
+}
+
 // TestTemplateNotFound generates an error (embedded default repository).
 func TestTemplateNotFound(t *testing.T) {
 	root := "testdata/example.com/testTemplateNotFound"
@@ -234,7 +259,6 @@ func TestTemplateNotFound(t *testing.T) {
 	}
 }
 
-// TODO: TestRuntimeNotFound in custom repository
 // TODO: TestTemplateNotFound in custom repository
 
 // TestNamed ensures that an explicitly passed name is used in leau of the

templates.go

@@ -90,23 +90,31 @@ func isCustom(template string) bool {
 	return len(strings.Split(template, "/")) > 1
 }
 
-func (t *templateWriter) writeCustom(repositories, runtime, template, dest string) error {
-	if repositories == "" {
+func (t *templateWriter) writeCustom(repositoriesPath, runtime, template, dest string) error {
+	if repositoriesPath == "" {
 		return ErrRepositoriesNotDefined
 	}
-	if !repositoryExists(repositories, template) {
+	if !repositoryExists(repositoriesPath, template) {
 		return ErrRepositoryNotFound
 	}
 	cc := strings.Split(template, "/")
 	if len(cc) < 2 {
 		return ErrTemplateMissingRepository
 	}
+	repositoriesFS := os.DirFS(repositoriesPath)
+
+	runtimePath := cc[0] + "/" + runtime
+	_, err := fs.Stat(repositoriesFS, runtimePath)
+	if errors.Is(err, fs.ErrNotExist) {
+		return ErrRuntimeNotFound
+	}
+
 	// ex: /home/alice/.config/func/repositories/boson/go/http
 	// Note that the FS instance returned by os.DirFS uses forward slashes
 	// internally, so source paths do not use the os path separator due to
 	// that breaking Windows.
 	src := cc[0] + "/" + runtime + "/" + cc[1]
-	return t.cp(src, dest, os.DirFS(repositories))
+	return t.cp(src, dest, repositoriesFS)
 }
 
 func (t *templateWriter) writeEmbedded(runtime, template, dest string) error {