shared_cleanup_stale_branch_caches.yml

# https://github.com/actions/cache/blob/main/tips-and-workarounds.md#force-deletion-of-caches-overriding-default-cache-eviction-policy

name: (Shared) Cleanup Stale Branch Caches
on:
  schedule:
    # Every 6 hours
    - cron: 0 */6 * * *
  workflow_dispatch:

permissions: {}

jobs:
  cleanup:
    runs-on: ubuntu-latest
    permissions:
      # `actions:write` permission is required to delete caches
      #   See also: https://docs.github.com/en/rest/actions/cache?apiVersion=2022-11-28#delete-a-github-actions-cache-for-a-repository-using-a-cache-id
      actions: write
      contents: read
    steps:
      - name: Cleanup
        run: |
          echo "Fetching list of cache keys"
          cacheKeysForPR=$(gh cache list --limit 100 --json id,ref --jq '.[] | select(.ref != "refs/heads/main") | .id')

          ## Setting this to not fail the workflow while deleting cache keys.
          set +e
          for cacheKey in $cacheKeysForPR
          do
              gh cache delete $cacheKey
              echo "Deleting $cacheKey"
          done
          echo "Done"
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          GH_REPO: ${{ github.repository }}