adds skip_templating feature (gruntwork-io#167)

README.md

@@ -155,6 +155,7 @@ Learn more about boilerplate in the following sections:
 1. [Dependencies](#dependencies)
 1. [Hooks](#hooks)
 1. [Skip Files](#skip-files)
+1. [Skip Templating](#skip-files)
 1. [Templates](#templates)
 1. [Validations](#validations)
 1. [Variable Ordering](#variable-ordering)
@@ -312,6 +313,9 @@ skip_files:
   - path: subfolder/README.md
     if: {{ not .ShowLogo }}
 
+skip_templating:
+  - path: subfolder/helm-charts/*
+
 engines:
   - path: subfolder/foo.json.jsonnet
     template_engine: jsonnet
@@ -392,6 +396,16 @@ values `"true"` or `"false"`.
 
 See the [Skip Files](#skip-files) section for more info.
 
+**Skip Templating**: Use *skip_templating* to specify files in the template folder that should not be parsed by the templating engine but will be copied to the `output-folder` with the same path and file name . The `path` field
+is the relative path from the template folder root (where the `boilerplate.yml` file is defined) of the file that should
+be copied without rendering. You can conditionally skip the templating of the file using the `if` field, which should either be a YAML boolean value
+(`true` or `false`), or Go templating syntax (which can use the boilerplate variables) that evaluates to the string
+values `"true"` or `"false"`.
+
+See the [Skip Files](#skip-files) section for more info on the configuration as the syntax is the same.
+
+If a file is listed in both `skip_files` and `skip_templating`, the file will be skipped entirely.
+
 **Engines**: Use *engines* to specify files in the template folder that should be rendered with an alternative
 templating engine. The `path` field is the relative path from the template folder root (where the `boilerplate.yml` file
 is defined) of the file that should use the alternative template engine.
@@ -586,11 +600,11 @@ Note the following:
 
 #### Skip Files
 
-You can specify files that should be excluded from the rendered output using the `skip_files` section in
-`boilerplate.yml`. This is most useful when you have templates that need to conditionally exclude files from the
-rendered folder list.
+You can specify files that should be excluded from the rendered output using the `skip_files`, or copied without rendering using the `skip_templating` sections in
+`boilerplate.yml`. `skip_files` is most useful when you have templates that need to conditionally exclude files from the
+rendered folder list. `skip_templating` is useful when you want to copy files without rendering them, such as files that contain syntax similar to the go templating syntax - such as helm charts.
 
-The `skip_files` section is a list of objects with the fields `path`, `not_path`, and `if`, where one of `path` or
+The `skip_files` and `skip_templating` sections are a list of objects with the fields `path`, `not_path`, and `if`, where one of `path` or
 `not_path` is required. When `path` is set, all files that match the `path` attribute will be skipped, while when
 `not_path` is set, all files that DO NOT match the `not_path` attribute are skipped (in other words, only paths that
 match `not_path` are kept).
@@ -608,6 +622,9 @@ Consider the following boilerplate template folder:
 .
 ├── boilerplate.yml
 ├── BOILERPLATE_README.md
+├── helm-charts
+    ├── Chart.yaml
+    └── values.yaml
 └── docs
     ├── README_WITH_ENCRYPTION.md
     └── README_WITHOUT_ENCRYPTION.md
@@ -638,11 +655,25 @@ This will:
 - Skip rendering `docs/README_WITH_ENCRYPTION.md` if `UseEncryption` is set to `false`.
 - If `DocsOnly` is set to `true`, only render the `docs` folder.
 
+Also suppose that you wanted to conditionally select which helm chart file to simly be copied, while rendering the variables. You can use `skip_templating`
+to implement this:
+
+```yaml
+skip_templating:
+  - path: "*/Chart.yaml"
+```
+
+This will:
+
+- Copy `helm-charts/Chart.yaml` to the `output-folder` without processing the file.
+
 For a more concise specification, you can use glob syntax in the `path` to match multiple paths in one entry:
 
 ```yaml
 skip_files:
   - path: "docs/**/*"
+skip_templating:
+  - path: "helm-charts/*"
 ```
 
 

config/config.go

@@ -27,6 +27,7 @@ type BoilerplateConfig struct {
 	Hooks           variables.Hooks
 	Partials        []string
 	SkipFiles       []variables.SkipFile
+	SkipTemplating  []variables.SkipFile
 	Engines         []variables.Engine
 }
 
@@ -76,11 +77,17 @@ func (config *BoilerplateConfig) UnmarshalYAML(unmarshal func(interface{}) error
 		return err
 	}
 
-	skipFiles, err := variables.UnmarshalSkipFilesFromBoilerplateConfigYaml(fields)
+	skipFiles, err := variables.UnmarshalSkipFilesFromBoilerplateConfigYaml(fields, "skip_files")
 	if err != nil {
 		return err
 	}
 
+	skipTemplating, err := variables.UnmarshalSkipFilesFromBoilerplateConfigYaml(fields, "skip_templating")
+	if err != nil {
+		return err
+	}
+
+
 	engines, err := variables.UnmarshalEnginesFromBoilerplateConfigYaml(fields)
 	if err != nil {
 		return err
@@ -93,6 +100,7 @@ func (config *BoilerplateConfig) UnmarshalYAML(unmarshal func(interface{}) error
 		Hooks:           hooks,
 		Partials:        partials,
 		SkipFiles:       skipFiles,
+		SkipTemplating:  skipTemplating,
 		Engines:         engines,
 	}
 	return nil
@@ -154,6 +162,20 @@ func (config *BoilerplateConfig) MarshalYAML() (interface{}, error) {
 		}
 		configYml["skip_files"] = skipFilesYml
 	}
+	if len(config.SkipTemplating) > 0 {
+		// Due to go type system, we can only pass through []interface{}, even though []SkipTemplating is technically
+		// polymorphic to that type. So we reconstruct the list using the right type before passing it in to the marshal
+		// function.
+		interfaceList := []interface{}{}
+		for _, skipTemplate := range config.SkipTemplating {
+			interfaceList = append(interfaceList, skipTemplate)
+		}
+		skipTemplatingYml, err := util.MarshalListOfObjectsToYAML(interfaceList)
+		if err != nil {
+			return nil, err
+		}
+		configYml["skip_templating"] = skipTemplatingYml
+	}
 	if len(config.Engines) > 0 {
 		// Due to go type system, we can only pass through []interface{}, even though []Engine is technically
 		// polymorphic to that type. So we reconstruct the list using the right type before passing it in to the marshal

config/config_test.go

@@ -711,6 +711,34 @@ func TestParseBoilerplateConfigWithSkipFiles(t *testing.T) {
 	assert.Equal(t, expected, actual)
 }
 
+// YAML is whitespace sensitive, so we need to be careful that we don't introduce unnecessary indentation
+const configWithSkipTemplating = `skip_templating:
+  - path: "docs/README_ALWAYS_SKIP.md"
+  - path: "docs/README_MAYBE_SKIP.md"
+    if: "{{ .MaybeSkip }}"
+  - not_path: "docs/**/*"
+    if: "{{ .DocsOnly }}"
+`
+
+func TestParseBoilerplateConfigWithSkipTemplating(t *testing.T) {
+	t.Parallel()
+
+	actual, err := ParseBoilerplateConfig([]byte(configWithSkipTemplating))
+	require.NoError(t, err)
+
+	expected := &BoilerplateConfig{
+		Variables:    []variables.Variable{},
+		Dependencies: []variables.Dependency{},
+		Hooks:        variables.Hooks{},
+		SkipTemplating: []variables.SkipFile{
+			{Path: "docs/README_ALWAYS_SKIP.md", If: ""},
+			{Path: "docs/README_MAYBE_SKIP.md", If: "{{ .MaybeSkip }}"},
+			{NotPath: "docs/**/*", If: "{{ .DocsOnly }}"},
+		},
+	}
+	assert.Equal(t, expected, actual)
+}
+
 func TestMarshalBoilerplateConfig(t *testing.T) {
 	t.Parallel()
 

examples/for-learning-and-testing/skip-templating/a/b/c/d.yml

@@ -0,0 +1 @@
+val: {{ VarVal }}

examples/for-learning-and-testing/skip-templating/a/b/c/e.yml

@@ -0,0 +1 @@
+val: {{ VarVal }}

examples/for-learning-and-testing/skip-templating/boilerplate.yml

@@ -0,0 +1,7 @@
+variables:
+  - name: VarVal
+    type: string
+    default: "val"
+
+skip_templating:
+  - path: "**/d.yml"

templates/template_processor.go

@@ -458,11 +458,15 @@ func processTemplateFolder(
 ) error {
 	util.Logger.Printf("Processing templates in %s and outputting generated files to %s", opts.TemplateFolder, opts.OutputFolder)
 
-	// Process and render skip files and engines before walking so we only do the rendering operation once.
+	// Process and render skip files, templates and engines before walking so we only do the rendering operation once.
 	processedSkipFiles, err := processSkipFiles(config.SkipFiles, opts, variables)
 	if err != nil {
 		return err
 	}
+	processedSkipTemplating, err := processSkipFiles(config.SkipTemplating, opts, variables)
+	if err != nil {
+		return err
+	}
 	processedEngines, err := processEngines(config.Engines, opts, variables)
 	if err != nil {
 		return err
@@ -477,7 +481,8 @@ func processTemplateFolder(
 			return createOutputDir(path, opts, variables)
 		} else {
 			engine := determineTemplateEngine(processedEngines, path)
-			return processFile(path, opts, variables, partials, engine)
+			skipTemplating := shouldSkipPath(path, opts, processedSkipTemplating)
+			return processFile(path, opts, variables, partials, skipTemplating, engine)
 		}
 	})
 }
@@ -489,8 +494,13 @@ func processFile(
 	opts *options.BoilerplateOptions,
 	variables map[string]interface{},
 	partials []string,
+	skipTemplating bool,
 	engine variables.TemplateEngineType,
 ) error {
+	if skipTemplating {
+		util.Logger.Printf("Skipping templating of %s", path)
+		return copyFile(path, opts, variables)
+	}
 	isText, err := util.IsTextFile(path)
 	if err != nil {
 		return err

test-fixtures/examples-expected-output/skip-templating/a/b/c/d.yml

@@ -0,0 +1 @@
+val: {{ VarVal }}

test-fixtures/examples-expected-output/skip-templating/a/b/c/e.yml

@@ -0,0 +1 @@
+val: val

variables/skip_files.go

@@ -2,7 +2,7 @@ package variables
 
 import "github.com/gruntwork-io/boilerplate/errors"
 
-// A single skip_file entry, which is a file that (conditionally) should be excluded from the rendered output.
+// A single skip_file or skip_templating entry, which is a file that (conditionally) should be excluded from the rendered output.
 type SkipFile struct {
 	Path    string
 	NotPath string
@@ -27,15 +27,15 @@ func (skipFile SkipFile) MarshalYAML() (interface{}, error) {
 
 // Given a list of key:value pairs read from a Boilerplate YAML config file of the format:
 //
-// skip_files:
+// (skip_files|skip_templating):
 //   - path: <PATH>
 //     if: <SKIPIF>
 //   - path: <PATH>
 //   - not_path: <PATH>
 //
 // convert to a list of SkipFile structs.
-func UnmarshalSkipFilesFromBoilerplateConfigYaml(fields map[string]interface{}) ([]SkipFile, error) {
-	rawSkipFiles, err := unmarshalListOfFields(fields, "skip_files")
+func UnmarshalSkipFilesFromBoilerplateConfigYaml(fields map[string]interface{}, fieldName string) ([]SkipFile, error) {
+	rawSkipFiles, err := unmarshalListOfFields(fields, fieldName)
 	if err != nil || rawSkipFiles == nil {
 		return nil, err
 	}