feature: Allow providing rc file (#392)

Closes #185

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## master (unreleased)
 
+- feature: Allow providing rc file ([PR #392](https://github.com/evilmartians/lefthook/pull/392) by @mrexox)
+
 ## 1.2.3 (2022-11-30)
 
 - feature: Expand env variables ([PR #391](https://github.com/evilmartians/lefthook/pull/391) by @mrexox)

docs/configuration.md

@@ -7,6 +7,7 @@
   - [`skip_output`](#skip_output)
   - [`source_dir`](#source_dir)
   - [`source_dir_local`](#source_dir_local)
+  - [`rc`](#rc)
 - [`remote` (Beta :test_tube:)](#remote)
   - [`git_url`](#git_url)
   - [`ref`](#ref)
@@ -140,6 +141,65 @@ Change a directory for *local* script files (not stored in VCS).
 
 This option is useful if you have a `lefthook-local.yml` config file and want to reference different scripts there.
 
+### `rc`
+
+Provide an [**rc**](https://www.baeldung.com/linux/rc-files) file, which is actually a simple `sh` script. Currently it can be used to set ENV variables that are not accessible from non-shell programs.
+
+**Example**
+
+Use cases:
+
+- You have a GUI program that runs git hooks (e.g., VSCode)
+- You reference executables that are accessible only from a tweaked $PATH environment variable (e.g., when using rbenv or nvm)
+- Or even if your GUI programm cannot locate the `lefthook` executable :scream:
+- Or if you want to use ENV variables that control the executables behavior in `lefthook.yml`
+
+```bash
+# An npm executable which is managed by nvm
+$ which npm
+/home/user/.nvm/versions/node/v15.14.0/bin/npm
+```
+
+```yml
+# lefthook.yml
+
+pre-commit:
+  commands:
+    lint:
+      run: npm run eslint {staged_files}
+```
+
+Provide a tweak to access `npm` executable the same way you do it in your ~/<shell>rc
+
+```yml
+# lefthook-local.yml
+
+# You can choose whatever name you want.
+# You can share it between projects where you use lefthook.
+# Make sure the path is absolute.
+rc: ~/.lefthookrc
+```
+
+```bash
+# ~/.lefthookrc
+
+# An nvm way
+
+export NVM_DIR="$HOME/.nvm"
+[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
+
+# Or maybe just
+
+PATH=$PATH:$HOME/.nvm/versions/node/v15.14.0/bin
+```
+
+```bash
+# Make sure you updated git hooks. This is important.
+$ lefthook install -f
+```
+
+Now any program that runs your hooks will have a tweaked PATH environment variable and will be able to get `nvm` :wink:
+
 ## `remote`
 
 > :test_tube: This feature is in **Beta** version

internal/config/config.go

@@ -12,6 +12,7 @@ type Config struct {
 	SkipOutput     []string `mapstructure:"skip_output"`
 	SourceDir      string   `mapstructure:"source_dir"`
 	SourceDirLocal string   `mapstructure:"source_dir_local"`
+	Rc             string   `mapstructure:"rc"`
 
 	Hooks map[string]*Hook
 }

internal/lefthook/add.go

@@ -35,7 +35,7 @@ func (l *Lefthook) Add(args *AddArgs) error {
 		return err
 	}
 
-	err = l.addHook(args.Hook)
+	err = l.addHook(args.Hook, "")
 	if err != nil {
 		return err
 	}

internal/lefthook/install.go

@@ -125,12 +125,12 @@ func (l *Lefthook) createHooksIfNeeded(cfg *config.Config, force bool) error {
 			return err
 		}
 
-		if err = l.addHook(hook); err != nil {
+		if err = l.addHook(hook, cfg.Rc); err != nil {
 			return err
 		}
 	}
 
-	if err = l.addHook(config.GhostHookName); err != nil {
+	if err = l.addHook(config.GhostHookName, cfg.Rc); err != nil {
 		return nil
 	}
 

internal/lefthook/lefthook.go

@@ -113,9 +113,9 @@ func (l *Lefthook) cleanHook(hook string, force bool) error {
 }
 
 // Creates a hook file using hook template.
-func (l *Lefthook) addHook(hook string) error {
+func (l *Lefthook) addHook(hook, rc string) error {
 	hookPath := filepath.Join(l.repo.HooksPath, hook)
 	return afero.WriteFile(
-		l.Fs, hookPath, templates.Hook(hook), hookFileMode,
+		l.Fs, hookPath, templates.Hook(hook, rc), hookFileMode,
 	)
 }

internal/templates/hook.tmpl

@@ -4,6 +4,12 @@ if [ "$LEFTHOOK" = "0" ]; then
   exit 0
 fi
 
+{{- if .Rc}}
+{{/* Load rc file and export all ENV vars defined in it */}}
+set -a
+[ -f '{{.Rc}}' ] && source '{{.Rc}}'
+{{- end}}
+
 call_lefthook()
 {
   dir="$(git rev-parse --show-toplevel)"

internal/templates/templates.go

@@ -16,14 +16,16 @@ var templatesFS embed.FS
 type hookTmplData struct {
 	HookName  string
 	Extension string
+	Rc        string
 }
 
-func Hook(hookName string) []byte {
+func Hook(hookName, rc string) []byte {
 	buf := &bytes.Buffer{}
 	t := template.Must(template.ParseFS(templatesFS, "hook.tmpl"))
 	err := t.Execute(buf, hookTmplData{
 		HookName:  hookName,
 		Extension: getExtension(),
+		Rc:        rc,
 	})
 	if err != nil {
 		panic(err)