Caching pre-commit with GitHub Actions

When setting up a GitHub Actions workflow for the repo that deploys this site, I noticed the pre-commit action for GitHub Actions is deprecated, and also doesn’t cache the installation of pre-commit itself.

As a workaround, you can easily use the package dependency caching in actions/setup-python to cache the pre-commit installation and a custom actions/cache to cache the pre-commit cache itself (~/.cache/pre-commit/).

• First, update or create requirements.txt with the current version of pre-commit:

  pip install pre-commit
  pip freeze|grep pre-commit >> requirements.txt
  

  Even if this file includes only the pre-commit package, you need a requirements.txt file for actions/setup-python to hash the cache key.

• Update your GitHub Actions workflow based on the following:

  name: pre-commit
  
  on:
    pull_request:
    push:
      branches: [main]
  
  jobs:
    pre-commit:
      runs-on: ubuntu-latest
      steps:
        - uses: actions/checkout@v3
        - uses: actions/setup-python@v3
          with:
            cache: 'pip'
        - run: python -m pip install -r requirements.txt
        - uses: actions/cache@v3
          with:
            path: ~/.cache/pre-commit/
            key: pre-commit-4|${{ env.pythonLocation }}|${{ hashFiles('.pre-commit-config.yaml') }}
        - run: pre-commit run --show-diff-on-failure --color=always --all-files