Merge pull request #328 from voxpupuli/add-blog-for-distro-puppet-acc…

…eptance-tests

Add a blog post on Distro Puppet acceptance testing

_posts/2023-10-25-distro-puppet-acceptance-tests.md

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+---
+layout: post
+title: Acceptance testing using distro Puppet versions
+date: 2023-10-25
+github_username: ekohl
+category: changelog
+---
+
+Vox Pupuli's CI now supports testing using distro Puppet versions.
+At the moment this is used for ArchLinux, Debian 12 and Fedora 37 & 38.
+
+Within Vox Pupuli we maintain a lot of modules.
+Keeping those healthy is a challenge and having working acceptance tests makes that feasible.
+For each operating system we need two things: a working (container) image and Puppet.
+The former is generally easy (except for operating systems with licenses), but for the latter we need some system packages.
+Until recently we've relied on Puppet's [RPM](https://yum.puppet.com/) and [deb](https://apt.puppet.com/) packages.
+This matches how most people consume Puppet, but Puppet's coverage of operating systems is incomplete.
+There are no packages for Archlinux and for the distributions that are supported, it doesn't have complete coverage.
+Now our tooling is enhanced to use the distribution's native packages.
+With this in place, it's possible to start supporting the recently released Debian 12.
+
+It's also a good chance to dive a bit deeper in how this is done.
+Back in February I gave [a talk](https://cfp.cfgmgmtcamp.org/2023/talk/DWBWFX/) on this, but there was a lot of information in there and written form may be useful.
+I'm not going to cover everything from my talk, but only focus on the acceptance test implementation.
+It heavily relies on dynamically generated matrices in GitHub Actions, which I've [written](https://partial.solutions/2023/advanced-matrix-testing-with-github-actions.html) about before.
+To generate this matrix, [puppet_metadata](https://github.com/voxpupuli/puppet_metadata) is used.
+
+How does `puppet_metadata` generate this matrix?
+It parses `metadata.json` and builds a [list of supported operating systems](https://github.com/voxpupuli/puppet_metadata/blob/ff57b5e1fbc5ea09c6d4e5ca91e8e983f56d5585/lib/puppet_metadata/github_actions.rb#L50-L75).
+For every operating system it iterates the OS releases (except for rolling releases like Archlinux and Gentoo).
+For each release, it iterates the supported Puppet versions (also derived from `metadata.json`) and checks if it can find a Puppet version.
+If there's an AIO (all-in-one) build (determined using [PuppetMetadata::AIO](https://github.com/voxpupuli/puppet_metadata/blob/master/lib/puppet_metadata/aio.rb)) then that's preferred.
+
+This gives us a list like:
+
+* Archlinux rolling - Distro Puppet
+* Debian 11 - Puppet 7
+* Debian 11 - Puppet 8
+* Debian 12 - Distro Puppet 7
+* CentOS 8 - Puppet 7
+* CentOS 8 - Puppet 8
+
+This is exported as a list of environment variables that [gha-puppet](https://github.com/voxpupuli/gha-puppet) can use in the [Beaker workflow](https://github.com/voxpupuli/gha-puppet/blob/v2/.github/workflows/beaker.yml).
+Note you need to be on v2 for this.
+In the `setup_matrix` job the matrix is generated by calling `metadata2gha` (from `puppet_metadata`) and used in the `acceptance` job.
+
+With all of this in place, how do you add support for a new Puppet version or a new OS version?
+Simply modify `metadata.json` and add Debian 12.
+It should now show up in the testing matrix.
+
+As for unit tests, [rspec-puppet-facts](https://github.com/voxpupuli/rspec-puppet-facts) and [FacterDB](https://github.com/voxpupuli/facterdb) provide similar functionality that relies on `metadata.json`.
+
+Once Puppet will support Debian 12, we will switch the OS testing to the official packages but it's now possible to move forward faster.