Notes from playing with grunt.js

grunt-notes.md

Last week I thought I'd move a few hundred lines of our build process from our custom build tool to grunt.

I ran into a problem with grunt.task.run queuing a task but not waiting for the task to complete before continuing or ensuring execution order (relevant testcase).

Maybe it was problem with the child processes not executing synchronously. I tried a few ways to run a synchronous child process in node:

• libc system call with node's FFI

• async child process with sleep/wait callbacks

• settimeout and assume it completes or you'd want to kill the task after a certain period of time

However, the docs and source say the job is queued but not run (even though the method is grunt.task.run). For example with the following grunt file:

module.exports = (grunt) ->

  grunt.registerTask 'pre-foo', ->
    console.log 'pre-foo'

  grunt.registerTask 'foo', ->
    grunt.task.run 'pre-foo'
    console.log 'foo'
    grunt.task.run 'post-foo'

  grunt.registerTask 'post-foo', ->
    console.log 'post-foo'

We get:

» grunt foo
Running "foo" task
foo

Running "pre-foo" task
pre-foo

Running "post-foo" task
post-foo

Done, without errors.

Grunt runs foo then drains the task queue running pre-foo then 'post-foo`. I refactored one task using the auto method from Async.js:

  grunt.registerTask 'tag-patch-version', ->
    done = @async()

    async.auto(
      # Don't need array if one callback
      bumpVersion: (callback) ->
        console.log 'bumpVersion'
        grunt.task._tasks['bump-version'].fn 'patch', null, callback

      updateVersion: ['bumpVersion', (callback) ->
        console.log 'UpdateVersion'
        cmd = """git add package.json && \
          git commit -m 'Update version' && \
          git checkout package.json"""
        grunt.helper 'grunt-exec-spawn', cmd, callback
      ]

      writeVersion: ['updateVersion', (callback) ->
        console.log "Write RELEASE-VERSION file"
        grunt.task._tasks['bump-version'].fn null, null, callback
      ]

      tagVersion: ['writeVersion', (callback) ->
        console.log "tag version"
        cmd = "git tag -a $(cat RELEASE-VERSION) -m $(cat RELEASE-VERSION)"
        grunt.helper 'grunt-exec-spawn', cmd, -> callback(); done()
      ]
    )

This gave me the nice Makefile format I wanted, but I had more code, needed all subtasks to take a callback, and needed to call the bump-version subtask through the private grunt.tasks._tasks ( the subtask wouldn't resolve it's dependencies if bump-version called a grunt clean task for instance).

Grunt.js does handle a lot of common JS build tasks well (the watchers are nice), but at this point I figured I'd wasted enough time trying to write a Makefile in grunt and switched to a plain Makefile.