[CAP-9513] add .gitignore and .env.example to workflows init scaffold (#358)

GitOrigin-RevId: 37b4df9a3d0a44dc87a3c6ad5932491d75011d24

Author: blue-keleher

pkg/workflows/scaffold/scaffold.go

@@ -306,6 +306,18 @@ func Scaffold(opts Options) (*Result, error) {
 		return nil, err
 	}
 
+	// Generate .gitignore if the template didn't provide one
+	createdFiles, err = writeIfNotExists(opts.Dir, ".gitignore", gitignoreContent(opts.Language), createdFiles)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create .gitignore: %w", err)
+	}
+
+	// Generate .env.example if the template didn't provide one
+	createdFiles, err = writeIfNotExists(opts.Dir, ".env.example", envExampleContent(), createdFiles)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create .env.example: %w", err)
+	}
+
 	// Support the old "additionalNextSteps" key as a fallback
 	nextSteps := meta.NextSteps
 	if len(nextSteps) == 0 && len(meta.LegacyNextSteps) > 0 {
@@ -364,6 +376,41 @@ func copyFile(src, dst string) error {
 	return err
 }
 
+// writeIfNotExists writes content to a file in dir only if it doesn't already
+// exist (e.g. provided by the template). If written, the filename is appended
+// to files and the updated slice is returned.
+func writeIfNotExists(dir, name, content string, files []string) ([]string, error) {
+	destPath := filepath.Join(dir, name)
+	if _, err := os.Stat(destPath); err == nil {
+		return files, nil // already exists from template
+	}
+	if err := os.WriteFile(destPath, []byte(content), 0o644); err != nil {
+		return files, err
+	}
+	return append(files, name), nil
+}
+
+// gitignoreContent returns the .gitignore contents for the given language.
+func gitignoreContent(lang Language) string {
+	var b strings.Builder
+	b.WriteString("dist/\n")
+	b.WriteString(".env\n")
+	b.WriteString(".DS_Store\n")
+	switch lang {
+	case Python:
+		b.WriteString(".venv/\n")
+		b.WriteString("__pycache__/\n")
+	case TypeScript:
+		b.WriteString("node_modules/\n")
+	}
+	return b.String()
+}
+
+// envExampleContent returns the .env.example file contents.
+func envExampleContent() string {
+	return "RENDER_API_KEY=\n"
+}
+
 // InitGitRepo initializes a new git repository in dir.
 func InitGitRepo(dir string) error {
 	_, err := git.PlainInitWithOptions(dir, &git.PlainInitOptions{

pkg/workflows/scaffold/scaffold_test.go

@@ -194,10 +194,10 @@ nextSteps:
 	assert.Equal(t, "render-workflows main:app", result.RenderStartCommand)
 	require.Len(t, result.NextSteps, 1)
 
-	expectedFiles := []string{"README.md", "main.py", "requirements.txt"}
+	expectedFiles := []string{"README.md", "main.py", "requirements.txt", ".gitignore", ".env.example"}
 	require.Len(t, result.Files, len(expectedFiles))
-	for i, f := range expectedFiles {
-		assert.Equal(t, f, result.Files[i])
+	for _, f := range expectedFiles {
+		assert.Contains(t, result.Files, f)
 
 		info, err := os.Stat(filepath.Join(outDir, f))
 		require.NoError(t, err, "expected file %s to exist", f)
@@ -229,11 +229,10 @@ startCommand: npx tsx src/index.ts
 	assert.Equal(t, TypeScript, result.Language)
 	assert.Equal(t, "npx tsx src/index.ts", result.StartCommand)
 
-	// WalkDir produces sorted order: README.md, package.json, src/index.ts, tsconfig.json
-	expectedFiles := []string{"README.md", "package.json", "src/index.ts", "tsconfig.json"}
+	expectedFiles := []string{"README.md", "package.json", "src/index.ts", "tsconfig.json", ".gitignore", ".env.example"}
 	require.Len(t, result.Files, len(expectedFiles))
-	for i, f := range expectedFiles {
-		assert.Equal(t, f, result.Files[i])
+	for _, f := range expectedFiles {
+		assert.Contains(t, result.Files, f)
 
 		info, err := os.Stat(filepath.Join(outDir, f))
 		require.NoError(t, err, "expected file %s to exist", f)
@@ -327,6 +326,86 @@ buildCommand: test-install
 	assert.Equal(t, expectedContent, string(got))
 }
 
+func TestScaffoldCreatesGitignore(t *testing.T) {
+	tests := []struct {
+		name   string
+		lang   Language
+		wantIn []string
+	}{
+		{"Python", Python, []string{"dist/", ".env", ".venv/", "__pycache__/"}},
+		{"TypeScript", TypeScript, []string{"dist/", ".env", "node_modules/"}},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			meta := "name: Test\nbuildCommand: test\n"
+			repoDir := setupFakeRepo(t, "test", meta, map[string]string{
+				"app.txt": "hello\n",
+			})
+
+			outDir := filepath.Join(t.TempDir(), "workflows")
+			_, err := Scaffold(Options{
+				Language:     tt.lang,
+				TemplateName: "test",
+				Dir:          outDir,
+				RepoDir:      repoDir,
+			})
+			require.NoError(t, err)
+
+			got, err := os.ReadFile(filepath.Join(outDir, ".gitignore"))
+			require.NoError(t, err)
+			for _, entry := range tt.wantIn {
+				assert.Contains(t, string(got), entry)
+			}
+		})
+	}
+}
+
+func TestScaffoldCreatesEnvExample(t *testing.T) {
+	meta := "name: Test\nbuildCommand: test\n"
+	repoDir := setupFakeRepo(t, "test", meta, map[string]string{
+		"app.txt": "hello\n",
+	})
+
+	outDir := filepath.Join(t.TempDir(), "workflows")
+	_, err := Scaffold(Options{
+		Language:     Python,
+		TemplateName: "test",
+		Dir:          outDir,
+		RepoDir:      repoDir,
+	})
+	require.NoError(t, err)
+
+	got, err := os.ReadFile(filepath.Join(outDir, ".env.example"))
+	require.NoError(t, err)
+	assert.Contains(t, string(got), "RENDER_API_KEY=")
+}
+
+func TestScaffoldDoesNotOverwriteTemplateFiles(t *testing.T) {
+	meta := "name: Test\nbuildCommand: test\n"
+	repoDir := setupFakeRepo(t, "test", meta, map[string]string{
+		"app.txt":      "hello\n",
+		".gitignore":   "custom-ignore\n",
+		".env.example": "CUSTOM_VAR=foo\n",
+	})
+
+	outDir := filepath.Join(t.TempDir(), "workflows")
+	_, err := Scaffold(Options{
+		Language:     Python,
+		TemplateName: "test",
+		Dir:          outDir,
+		RepoDir:      repoDir,
+	})
+	require.NoError(t, err)
+
+	gotGitignore, err := os.ReadFile(filepath.Join(outDir, ".gitignore"))
+	require.NoError(t, err)
+	assert.Equal(t, "custom-ignore\n", string(gotGitignore))
+
+	gotEnv, err := os.ReadFile(filepath.Join(outDir, ".env.example"))
+	require.NoError(t, err)
+	assert.Equal(t, "CUSTOM_VAR=foo\n", string(gotEnv))
+}
+
 func TestInitGitRepoUsesMainAsDefaultBranch(t *testing.T) {
 	dir := t.TempDir()