CoreOS repo templates

This repository includes parameterized templates for release checklists used by many different CoreOS repositories.

Structure of this repo

This repo contains rendering code, some GitHub Actions workflows, and the Tera templates and metadata that are rendered and submitted to downstream Git repos. Each Tera template has a adjacent .yaml file describing how the template will be applied, and there is also a top-level config.yaml tying everything together.

Tera templates are rendered with a "context", which is a set of key-value pairs that can be textually substituted into the template and can also affect control flow when rendering it. Context variables are provided via the YAML files.

config.yaml contains a list of downstream Git repos that we manage and a list of templates that we render. Each Git repo is associated with a short name, which the GitHub Actions workflow expects to match the repo name. config.yaml also defines global and repo-specific context variables.

Template YAML files contain a list of files, as (repo, path) tuples, to be derived from the corresponding template. Repos are referenced by their name in the config.yaml repo list. The template YAML also defines template-specific and file-specific context variables.

The sources of context variables, from highest to lowest precedence, are:

• File-specific vars in template YAML
• Repo-specific vars in config.yaml
• Global vars in template YAML
• Global vars in config.yaml

Modifying templates

To modify templated artifacts:

1. Clone this repo and make your changes locally. Run make to compare the resulting rendered files to the versions currently stored in the downstream repositories, or make output to generate a complete rendered tree for examination.

2. PR your changes. Reviewers can view the "Render diffs" step of the "Render" CI job to see the changes that will be PRed to the various repos.

3. Merge your changes. CI will automatically submit PRs to affected downstream repos.