feat: Adding custom default template (#3658)

Author: Tim Eijgelshoven

cli/commands/catalog/module/module.go

@@ -12,7 +12,7 @@ import (
 
 const (
 	defaultDescription   = "(no description found)"
-	maxDescriptionLenght = 200
+	maxDescriptionLength = 200
 )
 
 var (
@@ -86,7 +86,7 @@ func (module *Module) Title() string {
 
 // Description implements /github.com/charmbracelet/bubbles.list.DefaultItem.Description
 func (module *Module) Description() string {
-	if desc := module.Doc.Description(maxDescriptionLenght); desc != "" {
+	if desc := module.Doc.Description(maxDescriptionLength); desc != "" {
 		return desc
 	}
 

cli/commands/scaffold/action.go

@@ -221,62 +221,93 @@ func Run(ctx context.Context, opts *options.TerragruntOptions, moduleURL, templa
 	return nil
 }
 
-// prepareBoilerplateFiles prepares boilerplate files.
-func prepareBoilerplateFiles(ctx context.Context, opts *options.TerragruntOptions, templateURL string, tempDir string) (string, error) {
-	// identify template url
-	templateDir := ""
+// generateDefaultTemplate - write default template to provided dir
+func generateDefaultTemplate(boilerplateDir string) (string, error) {
+	const ownerWriteGlobalReadPerms = 0644
+	if err := os.WriteFile(util.JoinPath(boilerplateDir, "terragrunt.hcl"), []byte(DefaultTerragruntTemplate), ownerWriteGlobalReadPerms); err != nil {
+		return "", errors.New(err)
+	}
 
-	if templateURL != "" {
-		// process template url if was passed
-		parsedTemplateURL, err := tf.ToSourceURL(templateURL, tempDir)
-		if err != nil {
-			return "", errors.New(err)
-		}
+	if err := os.WriteFile(util.JoinPath(boilerplateDir, "boilerplate.yml"), []byte(DefaultBoilerplateConfig), ownerWriteGlobalReadPerms); err != nil {
+		return "", errors.New(err)
+	}
 
-		parsedTemplateURL, err = rewriteTemplateURL(ctx, opts, parsedTemplateURL)
-		if err != nil {
-			return "", errors.New(err)
-		}
-		// regenerate template url with all changes
-		templateURL = parsedTemplateURL.String()
+	return boilerplateDir, nil
+}
 
-		// prepare temporary directory for template
-		templateDir, err = os.MkdirTemp("", "template")
-		if err != nil {
-			return "", errors.New(err)
-		}
+// parseTemplateURL - parse URL and download files
+func parseTemplateURL(ctx context.Context, opts *options.TerragruntOptions, templateURL string, tempDir string) (string, error) {
+	parsedTemplateURL, err := tf.ToSourceURL(templateURL, tempDir)
+	if err != nil {
+		return "", errors.New(err)
+	}
 
-		// downloading template
-		opts.Logger.Infof("Using template from %s", templateURL)
+	parsedTemplateURL, err = rewriteTemplateURL(ctx, opts, parsedTemplateURL)
+	if err != nil {
+		return "", errors.New(err)
+	}
+	// regenerate template url with all changes
+	templateURL = parsedTemplateURL.String()
 
-		if _, err := getter.GetAny(ctx, templateDir, templateURL); err != nil {
-			return "", errors.New(err)
-		}
+	// prepare temporary directory for template
+	templateDir, err := os.MkdirTemp("", "template")
+	if err != nil {
+		return "", errors.New(err)
+	}
+
+	// downloading templateURL
+	opts.Logger.Infof("Using template from %s", templateURL)
+
+	if _, err := getter.GetAny(ctx, templateDir, templateURL); err != nil {
+		return "", errors.New(err)
 	}
-	// prepare boilerplate dir
+
+	return templateDir, nil
+}
+
+// prepareBoilerplateFiles - prepare boilerplate files from provided template, tf module, or (custom) default template
+func prepareBoilerplateFiles(ctx context.Context, opts *options.TerragruntOptions, templateURL string, tempDir string) (string, error) {
 	boilerplateDir := util.JoinPath(tempDir, util.DefaultBoilerplateDir)
-	// use template dir as boilerplate dir
-	if templateDir != "" {
-		boilerplateDir = templateDir
+
+	// process template url if it was passed. This overrides the .boilerplate folder in the OpenTofu/Terraform module
+	if templateURL != "" {
+		// process template url if it was passed
+		tempTemplateDir, err := parseTemplateURL(ctx, opts, templateURL, tempDir)
+		if err != nil {
+			return "", errors.New(err)
+		}
+
+		boilerplateDir = tempTemplateDir
 	}
 
 	// if boilerplate dir is not found, create one with default template
 	if !files.IsExistingDir(boilerplateDir) {
-		// no default boilerplate dir, create one
-		defaultTempDir, err := os.MkdirTemp("", "boilerplate")
+		config, err := config.ReadCatalogConfig(ctx, opts)
 		if err != nil {
 			return "", errors.New(err)
 		}
 
-		boilerplateDir = defaultTempDir
+		// use defaultTemplateURL if defined in config, otherwise use basic default template
+		if config != nil && config.DefaultTemplate != "" {
+			// process template url if available
+			tempTemplateDir, err := parseTemplateURL(ctx, opts, config.DefaultTemplate, tempDir)
+			if err != nil {
+				return "", errors.New(err)
+			}
 
-		const ownerWriteGlobalReadPerms = 0644
-		if err := os.WriteFile(util.JoinPath(boilerplateDir, "terragrunt.hcl"), []byte(DefaultTerragruntTemplate), ownerWriteGlobalReadPerms); err != nil {
-			return "", errors.New(err)
-		}
+			boilerplateDir = tempTemplateDir
+		} else {
+			defaultTempDir, err := os.MkdirTemp("", "boilerplate")
+			if err != nil {
+				return "", errors.New(err)
+			}
 
-		if err := os.WriteFile(util.JoinPath(boilerplateDir, "boilerplate.yml"), []byte(DefaultBoilerplateConfig), ownerWriteGlobalReadPerms); err != nil {
-			return "", errors.New(err)
+			boilerplateDir = defaultTempDir
+
+			boilerplateDir, err = generateDefaultTemplate(boilerplateDir)
+			if err != nil {
+				return "", errors.New(err)
+			}
 		}
 	}
 

config/catalog.go

@@ -37,11 +37,12 @@ var (
 )
 
 type CatalogConfig struct {
-	URLs []string `hcl:"urls,attr" cty:"urls"`
+	URLs            []string `hcl:"urls,attr" cty:"urls"`
+	DefaultTemplate string   `hcl:"default_template,attr" cty:"default_template"`
 }
 
 func (cfg *CatalogConfig) String() string {
-	return fmt.Sprintf("Catalog{URLs = %v}", cfg.URLs)
+	return fmt.Sprintf("Catalog{URLs = %v, DefaultTemplate = %v}", cfg.URLs, cfg.DefaultTemplate)
 }
 
 func (cfg *CatalogConfig) normalize(configPath string) {

config/catalog_test.go

@@ -125,6 +125,12 @@ func TestCatalogParseConfigFile(t *testing.T) {
 				},
 			},
 			nil,
+		}, {
+			filepath.Join(basePath, "config4.hcl"),
+			&config.CatalogConfig{
+				DefaultTemplate: "/test/fixtures/scaffold/external-template",
+			},
+			nil,
 		},
 	}
 

docs/_docs/02_features/05-catalog.md

@@ -23,13 +23,30 @@ terragrunt catalog <repo-url> [--no-include-root] [--root-file-name] [--output-f
 
 If `<repo-url>` is provided, the repository will be cloned into a temporary directory, otherwise:
 
-1. The repository list are searched in the config file `terragrunt.hcl`. if `terragrunt.hcl` does not exist in the current directory, the config are searched in the parent directories.
+1. The repository list are searched in the [config file](#configuration) `terragrunt.hcl`. if `terragrunt.hcl` does not exist in the current directory, the config are searched in the parent directories.
 1. If the repository list is not found in the configuration file, the modules are looked for in the current directory.
 
-An example of how to define the list of repositories for the `catalog` command in the `terragrunt.hcl` configuration file:
+The provided repositories will recursively be searched for OpenTofu/Terraform modules in the root of the repo and the `modules` directory. A table with all the discovered Terraform modules will subsequently be displayed. You can then:
+
+1. Search and filter the table: `/` and start typing.
+1. Select a module in the table: use the arrow keys to go up and down and next/previous page.
+1. See the docs for a selected module: `ENTER`.
+1. Use [`terragrunt scaffold`]({{site.baseurl}}/docs/features/scaffold/) to render a `terragrunt.hcl` for using the module: `S`.
+
+### Custom templates for scaffolding
+
+Terragrunt has a basic template built-in for rendering `terragrunt.hcl` files, but you can provide your own templates to customize what code is generated! Scaffolding is done via [boilerplate](https://github.com/gruntwork-io/boilerplate), and Terragrunt allows you to specify custom boilerplate templates via two mechanisms while using catalog:
+
+1. You can define a custom boilerplate template in a `.boilerplate` subfolder of your Terraform module.
+1. You can specify a custom boilerplate template in the [catalog config](#configuration).
+
+### Configuration
+
+An example of how to define the optional default template, and the list of repositories for the `catalog` command in the `terragrunt.hcl` configuration file:
 
 ``` hcl
 catalog {
+  default_template = "[email protected]/gruntwork-io/terragrunt.git//test/fixture-scaffold/external-template"
   urls = [
     "relative/path/to/repo", # will be converted to the absolute path, relative to the path of the configuration file.
     "/absolute/path/to/repo",
@@ -39,17 +56,10 @@ catalog {
 }
 ```
 
-This will recursively search for OpenTofu/Terraform modules in the root of the repo and the `modules` directory and show a table with all the modules. You can then:
-
-1. Search and filter the table: `/` and start typing.
-1. Select a module in the table: use the arrow keys to go up and down and next/previous page.
-1. See the docs for a selected module: `ENTER`.
-1. Use [`terragrunt scaffold`](https://terragrunt.gruntwork.io/docs/features/scaffold/) to render a `terragrunt.hcl` for using the module: `S`.
-
 ## Scaffolding Flags
 
 The following `catalog` flags control behavior of the underlying `scaffold` command when the `S` key is pressed in a catalog entry:
 
 - `--no-include-root` - Do not include the root configuration file in any generated `terragrunt.hcl` during scaffolding.
 - `--root-file-name` - The name of the root configuration file to include in any generated `terragrunt.hcl` during scaffolding. This value also controls the name of the root configuration file to search for when trying to determine Catalog urls.
-- `--output-folder` - Location for generated `terragrunt.hcl`. If flag is not provided current working directory is selected.
+- `--output-folder` - Location for generated `terragrunt.hcl`. If flag is not provided current working directory is selected.

docs/_docs/02_features/06-scaffold.md

@@ -68,10 +68,11 @@ Important notes:
 
 ## Custom templates for scaffolding
 
-Terragrunt has a basic template built-in for rendering `terragrunt.hcl` files, but you can provide your own templates to customize what code is generated! Scaffolding is done via [boilerplate](https://github.com/gruntwork-io/boilerplate), and Terragrunt allows you to specify custom boilerplate templates via two mechanisms:
+Terragrunt has a basic template built-in for rendering `terragrunt.hcl` files, but you can provide your own templates to customize what code is generated! Scaffolding is done via [boilerplate](https://github.com/gruntwork-io/boilerplate), and Terragrunt allows you to specify custom boilerplate templates via three mechanisms - listed in order of priority:
 
 1. You can specify a custom boilerplate template to use as the second argument of the `scaffold` command.
-1. You can define a custom boilerplate template in a `.boilerplate` subfolder of your module.
+1. You can define a custom boilerplate template in a `.boilerplate` subfolder of your Terraform module.
+1. You can define a default custom boilerplate template in the [catalog config]({{site.baseurl}}/docs/features/catalog/#configuration)
 
 If you define input variables in your boilerplate template, Terragrunt will prompt users for the values. Those values can also be passed in via `--var` and `--var-file` arguments.
 There are also a set of variables that Terragrunt will automatically expose to your boilerplate templates for rendering:

test/fixtures/catalog/config4.hcl

@@ -0,0 +1,7 @@
+locals {
+  baseRepo = "github.com/gruntwork-io"
+}
+
+catalog {
+  default_template = "/test/fixtures/scaffold/external-template"
+}