update-lifecycle.yml

name: Update lifecycle

on:
  schedule:
    # Every Monday at 8am UTC.
    - cron: '0 8 * * MON'
  workflow_dispatch:

jobs:
  update-lifecycle:
    name: Update lifecycle
    runs-on: pub-hk-ubuntu-22.04-small
    steps:
      - name: Get token for GH application (Linguist)
        uses: heroku/use-app-token-action@main
        id: generate-token
        with:
          app_id: ${{ vars.LINGUIST_GH_APP_ID }}
          private_key: ${{ secrets.LINGUIST_GH_PRIVATE_KEY }}

      - name: Checkout
        uses: actions/checkout@v4
        with:
          token: ${{ steps.generate-token.outputs.app_token }}

      - name: Record existing lifecycle version
        id: existing-version
        # Having to use grep instead of yq due to:
        # https://github.com/mikefarah/yq/issues/1758
        run: echo "version=$(grep --perl-regexp --null-data --only-matching '\[lifecycle\]\nversion = "\K([^"]+)' builder-22/builder.toml)" >> "${GITHUB_OUTPUT}"

      - name: Determine latest lifecycle version
        id: latest-version
        run: echo "version=$(gh release view --repo buildpacks/lifecycle --json tagName --jq '.tagName | sub("v"; "")')" >> "${GITHUB_OUTPUT}"

      - name: Update builder manifests with latest lifecycle version
        # This only updates manifests that were on the same version as builder-22, to ensure
        # that any legacy builder images pinned to older lifecycle versions are not updated too.
        run: sed --in-place --expression 's/^version = "${{ steps.existing-version.outputs.version }}"$/version = "${{ steps.latest-version.outputs.version }}"/' */builder.toml

      # This step will skip creating a PR if there are no changes to commit.
      - name: Create pull request
        id: pr
        uses: peter-evans/create-pull-request@v5.0.2
        with:
          token: ${{ steps.generate-token.outputs.app_token }}
          title: Update lifecycle from v${{ steps.existing-version.outputs.version }} to v${{ steps.latest-version.outputs.version }}
          body: |
            Release notes:
            https://github.com/buildpacks/lifecycle/releases/tag/v${{ steps.latest-version.outputs.version }}

            Full changelog:
            https://github.com/buildpacks/lifecycle/compare/v${{ steps.existing-version.outputs.version }}...v${{ steps.latest-version.outputs.version }}
          commit-message: |
            Update lifecycle from v${{ steps.existing-version.outputs.version }} to v${{ steps.latest-version.outputs.version }}

            Release notes:
            https://github.com/buildpacks/lifecycle/releases/tag/v${{ steps.latest-version.outputs.version }}

            Full changelog:
            https://github.com/buildpacks/lifecycle/compare/v${{ steps.existing-version.outputs.version }}...v${{ steps.latest-version.outputs.version }}
          branch: update-lifecycle
          delete-branch: true
          committer: ${{ vars.LINGUIST_GH_APP_USERNAME }} <${{ vars.LINGUIST_GH_APP_EMAIL }}>
          author: ${{ vars.LINGUIST_GH_APP_USERNAME }} <${{ vars.LINGUIST_GH_APP_EMAIL }}>

      - name: Enable PR auto-merge
        if: steps.pr.outputs.pull-request-operation == 'created'
        run: gh pr merge --auto --squash "${{ steps.pr.outputs.pull-request-number }}"
        env:
          GH_TOKEN: ${{ steps.generate-token.outputs.app_token }}