chef-runner

When it comes to dev/testing, fast feedback is everything. Vagrant needs >5s before it even starts provisioning. Each time. Let's fix that. -- @mlafeldt (1 Nov 2013)

What is chef-runner?

• A little tool that speeds up your Chef development and testing workflow.
• A fast alternative to the painfully slow vagrant provision.
• Allows you to change infrastructure code and get immediate feedback.
• Integrates with Vim so you don't have to leave your editor while hacking on recipes.

Here's a demo video that shows how chef-runner compares to vagrant provision in terms of speed.

How does it work?

• Directly executes Chef Solo over (plain) SSH without the overhead of vagrant provision.
• Only applies the Chef recipe you've actually modified by overriding Chef's run list.
• Integrates well with Vagrant: provisioning works as long the VM is running and /vagrant is mounted.
• Installs cookbook dependencies with Berkshelf and updates changes with lightning-fast rsync.

Requirements

To use chef-runner, you need the following software:

• bash or dash shell to run the chef-runner shell script
• VirtualBox or whatever you use with Vagrant
• Vagrant - version 1.3.4 or higher
• Berkshelf - installable via bundle install
• rsync
• ssh

Additionally, your cookbook must have the following files:

• metadata.rb - must define the cookbook's name
• Berksfile - must contain the metadata source
• Vagrantfile - optionally configures Chef Solo

To give you an example, the Practicing Ruby cookbook is known to work well with chef-runner.

Installation

Simply copy the shell script bin/chef-runner to your path. ~/bin is a great place for it. If you don't currently have a ~/bin, just do mkdir ~/bin and add export PATH="$HOME/bin:$PATH" to your .bashrc, .zshrc, etc.

Usage

Command Line Reference

chef-runner is a simple command-line tool that has a couple of options:

Usage: chef-runner [options] [--] [<recipe>...]

    -h, --help                   Show help text
    -H, --host <name>            Set hostname for direct SSH access
    -M, --machine <name>         Set name of Vagrant virtual machine

Options that will be passed to Chef Solo:

    -F, --format <format>        Set output format (null, doc, minimal, min)
                                 default: null
    -l, --log_level <level>      Set log level (debug, info, warn, error, fatal)
                                 default: info
    -j, --json-attributes <file> Load attributes from a JSON file

Running Chef Recipes

Before you use chef-runner, make sure that the Vagrant machine you want to provision is running in the background. You can check the status with vagrant status. If the machine isn't up yet, run vagrant up.

chef-runner executes one or more recipes you pass on the command line, in the exact order given. The tool has a flexible recipe syntax allowing you to compose your run list in multiple ways.

1. Run default recipe when passing no arguments:

   $ chef-runner

2. Run local recipe when passing filename:

   $ chef-runner recipes/foo.rb

3. Run local recipe when passing recipe name:

   $ chef-runner foo

4. Run external recipe when passing cookbook::recipe:

   $ chef-runner dogs::bar

5. Run multiple recipes (of mixed type) in order given:

   $ chef-runner recipes/foo.rb bar dogs::baz

Moreover, chef-runner allows you to load node attributes from a JSON file (that is located inside your cookbook):

$ chef-runner -j chef.json

Last but not least, you can configure both output format and log level of Chef:

$ chef-runner -F doc -l warn

Setting up SSH

chef-runner uses ssh to execute commands on Vagrant machines. If your Vagrantfile only defines a single machine, you don't need to worry about SSH at all -- simply run chef-runner and it should work.

In a multi-machine environment, you need to specify what Vagrant machine you want to use. There are two ways to do this.

1. Use the -M option (or --machine) to set the name of the Vagrant machine. The machine name is the name you have defined in your Vagrantfile. To get a list of all machine names, run vagrant status.

Example:

$ chef-runner -M db

2. Use the -H option (or --host) to set a hostname that was configured for direct SSH access to the Vagrant machine. This requires that your machine has a static IP address and that your ~/.ssh/config file has a configuration section for that hostname (vagrant ssh-config can help you here). While this option needs more setup work, SSH access is a bit faster compared to -M.

Example:

$ chef-runner -H example.local

Use with Vim

As a matter of fact, I primarily wrote chef-runner for use with Vim. Instead of jumping back and forth between editing a Chef recipe and running vagrant provision, I wanted to be able to change some code and get immediate feedback without having to leave the editor. This is where chef-runner's ability to run a single recipe file -- the file currently open in Vim -- comes in handy.

There's no Vim plugin (yet). For now, you can just stick this one-liner in your .vimrc:

nnoremap <leader>r :w\|!chef-runner %<cr>

With this key mapping in place, make sure that the Vagrant machine is up and open a recipe in Vim:

$ vagrant up
$ vim recipes/default.rb

Now whenever you type <leader>r (your leader key then r), chef-runner will run the current recipe inside the Vagrant machine, giving you fast feedback on local code changes. (As a bonus, the mapping will also save the file for you.)

Of course, you can also change the key mapping to include whatever chef-runner options you need. For example, I like using a Chef output format that is less verbose:

nnoremap <leader>r :w\|!chef-runner -F min -l warn %<cr>

Last but not least, you can always reprogram the Vim key mapping at runtime if you need to pass project-specific options like host or machine name:

:nnoremap <leader>r :w\|!chef-runner -F min -l warn -H example.local %<cr>

More Tips

You can further speed up working with chef-runner by doing the following:

• Split up Chef recipes into smaller logical chunks and include those chunks using the include_recipe method (good example).
• Use vagrant-cachier to share a common package cache among Vagrant machines.
• Enable SSH connection sharing and persistence to speed up repeated SSH connections.

Testing

chef-runner comes with a couple of Cucumber features that help to ensure the tool works as expected. You can run all features this way:

$ bundle install
$ bundle exec cucumber

License and Author

Author:: Mathias Lafeldt ([email protected])

Copyright:: 2013, Mathias Lafeldt

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Contributing

We welcome contributed improvements and bug fixes via the usual workflow:

1. Fork this repository
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new pull request