dependabot_reviewer.yml

# Auto-merge as documented in official Github docs
# https://docs.github.com/en/code-security/dependabot/working-with-dependabot/automating-dependabot-with-github-actions

name: Auto-review Dependabot PRs
on: pull_request_target

permissions:
  pull-requests: write
  contents: write

jobs:
  dependabot-reviewer:
    runs-on: ubuntu-latest

    if: ${{ github.event.pull_request.user.login == 'dependabot[bot]' }}
    
    steps:
      - name: Checkout Repository
        uses: actions/checkout@v4

      - name: Dependabot metadata
        id: metadata
        uses: dependabot/fetch-metadata@v1.7.0
        with:
          github-token: "${{ secrets.GITHUB_TOKEN }}"

      - name: Check allowlist
        id: check-allowlist
        if: steps.metadata.outputs.update-type == 'version-update:semver-patch' || steps.metadata.outputs.update-type == 'version-update:semver-minor'
        run: |
          cfg_path=".github/workflows/allowlist.json"
          IFS=', ' read -r -a libsUpdated <<< "${{ steps.metadata.outputs.dependency-names }}"
          # Loop through the array to make sure all updated libraries are in the allowlist
          all_in_allowlist="true"
          reason_array=()

          # If any element is not in the allowlist, set the flag to false
          for lib in "${libsUpdated[@]}"; do
            exists=$(jq --arg lib "$lib" 'any(.[]; .name == $lib)' $cfg_path)
            if [[ "$exists" != "true" ]]; then
              all_in_allowlist="false"
              break
            else
              reason_array+=("$(jq -r --arg lib "$lib" '.[] | select(.name == $lib) | .reason' $cfg_path)")
            fi
          done

          if [[ "$all_in_allowlist" == "true" ]]; then
            reasons=$(IFS=','; echo "${reason_array[*]}")
            echo "reasons=$reasons" >> $GITHUB_OUTPUT
            echo "allInAllowlist=true" >> $GITHUB_OUTPUT
          else
            echo "allInAllowlist=false" >> $GITHUB_OUTPUT
          fi

      - name: Approve and auto-merge
        if: steps.check-allowlist.conclusion == 'success' && steps.check-allowlist.outputs.allInAllowlist == 'true'
        run: |
          gh pr merge --auto --squash "$PR_URL"
          gh pr review $PR_URL \
          --approve -b "**I'm approving** this pull request because it includes a patch or minor \
          update to dependencies that are already in the allowlist.

          The reason this library is in the allowlist is that ${{ steps.check-allowlist.outputs.reasons}}"
        env:
          PR_URL: ${{github.event.pull_request.html_url}}
          GITHUB_TOKEN: ${{secrets.GH_BOT_ACCESS_TOKEN}}

      - name: Manual review is required
        if: steps.check-allowlist.conclusion != 'success' || steps.check-allowlist.outputs.allInAllowlist == 'false'
        run: |
          gh pr comment $PR_URL --body "**This library is not auto-approved**

          Unfortunately, this library is a major version update or it is not included in our allowlist, which means it cannot be auto-approved. \
          If you believe it should be considered for auto-approval, please open a pull request to add \
          it to the allowlist configuration. 

          To add this library to the allowlist, please modify the [allowlist.json](https://github.com/grafana/mimir/tree/main/.github/workflows/allowlist.json) file and \
          include the necessary details for review."

        env:
          PR_URL: ${{github.event.pull_request.html_url}}
          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}