Pkl as a Templating Engine for Crossplane Compositions

[Avarei]

Hey Everyone,

I've recently released an extension to Crossplane that allows it to use Pkl to render 'Managed Resources' like Kubernetes Manifests, or Cloud Resources.

Crossplane paves a path to create Kubernetes Custom Resource Definitions and composing logic what should happen with Custom Resources of that type.
This logic can now also be written in Pkl.

GitHub Repo
Marketplace

Here is list of tools used from the Pkl world to get all of it to work :)

• The 'Composition Function' uses pkl-go to render user-provided templates
• It implements a Custom Reader, which exposes contextual information to template
• This custom Reader is accessed using a custom parser based on k8s.contrib from pkl-pantry to parse inputs, which contain, among other things Kubernetes Resources
• It offers an adapted version of k8s.contrib.crd from pkl-pantry to generate XRDs (Composite Resource Definitions) from yaml files
• To release the Pkl Packages the pipeline uses the setup-pkl Github Action from the Community

The Package also ships with Modules to optionally develop everything that would have previously been written in Yaml using Pkl instead to allow for development without context-switches.

A full example is available in the repo at crossplane.contrib.example.