A template for Puppet modules

Feb 5, 2014 · 3 minute read

A little while ago I published a template writing your own puppet modules. It’s very opinionated but comes out of the box with lots of the tools you eventually find and add to your tool box. I’m posting this as it came up at the recent Configuration Management Camp and after discussing it I realised I hadn’t actually wrote anything about it anywhere.

What do you get?

A simple install, config, service class pattern
Unit tests with rspec-puppet
Rake tasks for linting and syntax checking
Integration tests using Beaker
A Modulefile to provide Forge metadata
Command line tools to upload to the Forge with blacksmith
A README based on the Puppetlabs documentation standards
Travis CI configuration based on the official Puppetlabs support matrix
A Guardfile which can run all the tests when you change manifests

Obviously you can choose not to use parts of this, or even delete aspects, but I find that approach much quicker than starting from scratch or copying files from previous modules and changing names.

How can I use it?

Simple. The following will install the module skeleton to ~/.puppet/var/puppet-module/skeleton. This turns out to be picked up by the Puppet module tool.

git clone https://github.com/garethr/puppet-module-skeleton 
cd puppet-module-skeleton
find skeleton -type f | git checkout-index --stdin --force --prefix="$HOME/.puppet/var/puppet-module/" --

With that in place you can then just run the following to create a new module, where puppet-ntp is the name of our new module.

puppet module generate puppet-ntp

We use puppet module like this rather than just copying the files because otherwise you would have to rename everything from class names to test assertions. The skeleton actually contains erb templates in places, and running puppet module generate results in the module name being available to those templates.

Now what?

Assuming you have run the above commands you should have a folder called puppet-ntp in your current directory. cd into that and then install the dependencies:

bundle install

Bundler is a dependency manager for Ruby. If you don’t already have it installed you should be able to do so with the following:

gem install bundler

Now you have the dependencies why not run the full test suite? This checks syntax, lints the Puppet code and runs the unit tests.

bundle exec rake test

Unit tests give fast feedback and help make sure the code you write is going to do what you intend, but they aren’t actually applying the manifests to a real machine. For that you want an integration test. You’ll need Vagrant installed for this next step. Lets run those as well with:

bundle exec rspec spec/acceptance

This will take a while, especially the first time. This uses Beaker to download a virtual machine from Puppetlabs (if you don’t already have it) and then brings up a new machine, applies a simple manifest, runs the acceptance tests and then destroys the machine.

The CONTRIBUTING.md file has more information for running the test suite.

What’s new?

I’ve recently added a Guardfile to help with testing. You can run this with:

bundle exec guard

Now in a separate tab or pane make a change to any of the manifests. The tests should run automatically in the tab or pane where guard is running.

Can you add this new tool?