generate_buildpack_bump_pr.yml

on:
  workflow_dispatch:
  schedule:
    - cron: "0 9 1 * *"

env:
  GO_VERSION: "1.20"
  GIT_AUTHOR_NAME: github-actions
  GIT_AUTHOR_EMAIL: github-actions@github.com
  GITHUB_UNPRIV_USERNAME: ${{ secrets.GOVUK_PAAS_UNPRIVILEGED_BOT_USERNAME }}

jobs:
  generate-buildpack-bump-pr:
    runs-on: ubuntu-latest
    steps:
      ## Setup
      - name: Checkout repo
        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608
        with:
          submodules: true
          # auth will be retained by repo configuration
          token: ${{ secrets.GOVUK_PAAS_UNPRIVILEGED_BOT_PAT }}

      - name: Install gettext
        run: |
          sudo apt install gettext
          # for envsubst

      - name: "Install Go ${{env.GO_VERSION}}"
        uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe
        with:
          go-version: "${{env.GO_VERSION}}"

      - name: "Install yq"
        run: |
          go install github.com/mikefarah/yq/v4@5ef537f3fd1a9437aa3ee44c32c6459a126efdc4  # v4.34.1

      - name: generate-buildpacks-yml
        run: |
          ./scripts/update_buildpacks.sh

      - name: Commit and push
        run: |
          export NEW_BRANCH_NAME="auto-bump-buildpacks-$(date -u '+%Y%m%dT%H%M')"
          export GIT_COMMITTER_EMAIL=$GIT_AUTHOR_EMAIL
          export GIT_COMMITTER_NAME=$GIT_AUTHOR_NAME

          git remote add unpriv-fork "https://github.com/${GITHUB_UNPRIV_USERNAME}/paas-cf.git"

          git checkout -b "$NEW_BRANCH_NAME"
          git add config/buildpacks.yml
          git add config/buildpacks.rolling.yml
          git commit -m 'bump buildpacks'
          git push unpriv-fork "$NEW_BRANCH_NAME"
          echo "NEW_BRANCH_NAME=$NEW_BRANCH_NAME" >> $GITHUB_ENV

      - name: Create PR
        env:
          GITHUB_TOKEN: ${{ secrets.GOVUK_PAAS_UNPRIVILEGED_BOT_PAT }}
        run: |
          FINAL_BODY=$(mktemp)
          envsubst < ./.github/workflows/automatic_buildpack_bump_pr_body.md > $FINAL_BODY

          gh pr create \
            --base main \
            --head "$GITHUB_UNPRIV_USERNAME:$NEW_BRANCH_NAME" \
            --title "Buildpack upgrades, $(date -u '+%B %Y')" \
            --body-file "$FINAL_BODY"