Merge pull request #728 from twpayne/execute-template-improvements

cmd/executetemplate.go

@@ -1,6 +1,7 @@
 package cmd
 
 import (
+	"bytes"
 	"io/ioutil"
 	"strconv"
 
@@ -9,6 +10,7 @@ import (
 
 type executeTemplateCmdConfig struct {
 	init         bool
+	output       string
 	promptString map[string]string
 }
 
@@ -26,6 +28,7 @@ func init() {
 
 	persistentFlags := executeTemplateCmd.PersistentFlags()
 	persistentFlags.BoolVarP(&config.executeTemplate.init, "init", "i", false, "simulate chezmoi init")
+	persistentFlags.StringVarP(&config.executeTemplate.output, "output", "o", "", "output filename")
 	persistentFlags.StringToStringVarP(&config.executeTemplate.promptString, "promptString", "p", nil, "simulate promptString")
 }
 
@@ -43,6 +46,7 @@ func (c *Config) runExecuteTemplateCmd(cmd *cobra.Command, args []string) error
 	if err != nil {
 		return err
 	}
+	output := &bytes.Buffer{}
 	switch len(args) {
 	case 0:
 		data, err := ioutil.ReadAll(c.Stdin)
@@ -53,18 +57,24 @@ func (c *Config) runExecuteTemplateCmd(cmd *cobra.Command, args []string) error
 		if err != nil {
 			return err
 		}
-		_, err = c.Stdout.Write(result)
-		return err
+		if _, err = output.Write(result); err != nil {
+			return err
+		}
 	default:
 		for i, arg := range args {
 			result, err := ts.ExecuteTemplateData("arg"+strconv.Itoa(i+1), []byte(arg))
 			if err != nil {
 				return err
 			}
-			if _, err := c.Stdout.Write(result); err != nil {
+			if _, err := output.Write(result); err != nil {
 				return err
 			}
 		}
-		return nil
 	}
+
+	if c.executeTemplate.output == "" {
+		_, err = c.Stdout.Write(output.Bytes())
+		return err
+	}
+	return c.fs.WriteFile(c.executeTemplate.output, output.Bytes(), 0o666)
 }

completions/chezmoi-completion.bash

@@ -916,6 +916,9 @@ _chezmoi_execute-template()
 
     flags+=("--init")
     flags+=("-i")
+    flags+=("--output=")
+    two_word_flags+=("--output")
+    two_word_flags+=("-o")
     flags+=("--promptString=")
     two_word_flags+=("--promptString")
     two_word_flags+=("-p")

completions/chezmoi.zsh

@@ -418,6 +418,7 @@ function _chezmoi_edit-config {
 function _chezmoi_execute-template {
   _arguments \
     '(-i --init)'{-i,--init}'[simulate chezmoi init]' \
+    '(-o --output)'{-o,--output}'[output filename]:' \
     '(-p --promptString)'{-p,--promptString}'[simulate promptString]:' \
     '--color[colorize diffs]:' \
     '(-c --config)'{-c,--config}'[config file]:' \

docs/FAQ.md

@@ -16,7 +16,7 @@
 * [gpg encryption fails. What could be wrong?](#gpg-encryption-fails-what-could-be-wrong)
 * [I'm getting errors trying to build chezmoi from source](#im-getting-errors-trying-to-build-chezmoi-from-source)
 * [What inspired chezmoi?](#what-inspired-chezmoi)
-* [Can I use chezmoi outside my home directory?](#can-i-use-chezmoi-outside-my-home-directory)
+* [Can I use chezmoi to manage files outside my home directory?](#can-i-use-chezmoi-to-manage-files-outside-my-home-directory)
 * [Where does the name "chezmoi" come from?](#where-does-the-name-chezmoi-come-from)
 * [What other questions have been asked about chezmoi?](#what-other-questions-have-been-asked-about-chezmoi)
 * [Where do I ask a question that isn't answered here?](#where-do-i-ask-a-question-that-isnt-answered-here)
@@ -213,16 +213,42 @@ Puppet is a slow overkill for managing your personal configuration files. The
 focus of chezmoi will always be personal home directory management. If your
 needs grow beyond that, switch to a whole system configuration management tool.
 
-## Can I use chezmoi outside my home directory?
-
-chezmoi, by default, operates on your home directory, but this can be overridden
-with the `--destination` command line flag or by specifying `destDir` in your config
-file. In theory, you could use chezmoi to manage any aspect of your filesystem.
-That said, although you can do this, you probably shouldn't. Existing
-configuration management tools like [Puppet](https://puppet.com/),
-[Chef](https://www.chef.io/chef/), [Ansible](https://www.ansible.com/), and
-[Salt](https://www.saltstack.com/) are much better suited to whole system
-configuration management.
+## Can I use chezmoi to manage files outside my home directory?
+
+In practice, yes, you can, but this is strongly discouraged beyond using your
+system's package manager to install the packages you need.
+
+chezmoi is designed to operate on your home directory, and is explicitly not a
+full system configuration management tool. That said, there are some ways to
+have chezmoi manage a few files outside your home directory.
+
+chezmoi's scripts can execute arbitrary commands, so you can use a `run_` script
+that is run every time you run `chezmoi apply`, to, for example:
+
+* Make the target file outside your home directory a symlink to a file managed
+  by chezmoi in your home directory.
+* Copy a file managed by chezmoi inside your home directory to the target file.
+* Execute a template with `chezmoi execute-template --output=filename template`
+  where `filename` is outside the target directory.
+
+chezmoi executes all scripts as the user executing chezmoi, so you may need to
+add extra privilege elevation commands like `sudo` or `PowerShell start -verb
+runas -wait` to your script.
+
+chezmoi, by default, operates on your home directory but this can be overridden
+with the `--destination` command line flag or by specifying `destDir` in your
+config file, and could even be the root directory (`/` or `C:\`). This allows
+you, in theory, to use chezmoi to manage any file in your filesystem, but this
+usage is extremely strongly discouraged.
+
+If your needs extend beyond modifying a handful of files outside your target
+system, then existing configuration management tools like
+[Puppet](https://puppet.com/), [Chef](https://www.chef.io/chef/),
+[Ansible](https://www.ansible.com/), and [Salt](https://www.saltstack.com/) are
+much better suited - and of couse can be called from a chezmoi `run_` script.
+Put your Puppet Manifests, Chef Recipes, Ansible Modules, and Salt Modules in a
+directory ignored by `.chezmoiignore` so they do not pollute your home
+directory. 
 
 ## Where does the name "chezmoi" come from?
 

docs/REFERENCE.md

@@ -582,15 +582,19 @@ Edit the configuration file.
 
 ### `execute-template` [*templates*]
 
-Write the result of evaluating *templates* to stdout. This is useful for testing
-templates or for calling chezmoi from other scripts. *templates* are interpeted
-as literal template data, with no whitespace added to the output between
-arguments. If no templates are specified, the template data are read from stdin.
+Execute *templates*. This is useful for testing templates or for calling chezmoi
+from other scripts. *templates* are interpeted as literal templates, with no
+whitespace added to the output between arguments. If no templates are specified,
+the template is read from stdin.
 
 #### `--init`, `-i`
 
 Include simulated functions only available during `chezmoi init`.
 
+#### '--output', '-o' *filename*
+
+Write the output to *filename* instead of stdout.
+
 #### `--promptString`, `-p` *pairs*
 
 Simulate the `promptString` function with a function that returns values from