Dependabot auto-merge workflow (prometheus/prometheus)

A

CI health grade

85/100

Health score

1

Job per trigger

2

Fixes in the optimized version

What it does

This is the Dependabot auto-merge workflow from the prometheus/prometheus repository, a real project running GitHub Actions. It is shown here with attribution under its Apache-2.0 license.

Below, Latchkey shows a faster, safer version produced by its optimization engine.

The workflow

---
name: Dependabot auto-merge
on: pull_request

concurrency:
  group: ${{ github.workflow }}-${{ (github.event.pull_request && github.event.pull_request.number) || github.ref || github.run_id }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  dependabot:
    permissions:
      contents: write
      pull-requests: write
    runs-on: ubuntu-latest
    if: ${{ github.event.pull_request.user.login == 'dependabot[bot]' && github.repository_owner == 'prometheus' }}
    steps:
    - name: Dependabot metadata
      id: metadata
      uses: dependabot/fetch-metadata@25dd0e34f4fe68f24cc83900b1fe3fe149efef98 # v3.1.0
      with:
        github-token: "${{ secrets.GITHUB_TOKEN }}"
    - name: Enable auto-merge for Dependabot PRs
      if: ${{steps.metadata.outputs.update-type == 'version-update:semver-minor' || steps.metadata.outputs.update-type == 'version-update:semver-patch'}}
      run: gh pr merge --auto --merge "$PR_URL"
      env:
        PR_URL: ${{github.event.pull_request.html_url}}
        GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}

The same workflow, on Latchkey

Removes redundant runs and caps runaway jobs. Added and changed lines are highlighted.

---
name: Dependabot auto-merge
on: pull_request

concurrency:
  group: ${{ github.workflow }}-${{ (github.event.pull_request && github.event.pull_request.number) || github.ref || github.run_id }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  dependabot:
    timeout-minutes: 30
    permissions:
      contents: write
      pull-requests: write
    runs-on: ubuntu-latest
    runs-on: latchkey-small
    if: ${{ github.event.pull_request.user.login == 'dependabot[bot]' && github.repository_owner == 'prometheus' }}
    steps:
    - name: Dependabot metadata
      id: metadata
      uses: dependabot/fetch-metadata@25dd0e34f4fe68f24cc83900b1fe3fe149efef98 # v3.1.0
      with:
        github-token: "${{ secrets.GITHUB_TOKEN }}"
    - name: Enable auto-merge for Dependabot PRs
      if: ${{steps.metadata.outputs.update-type == 'version-update:semver-minor' || steps.metadata.outputs.update-type == 'version-update:semver-patch'}}
      run: gh pr merge --auto --merge "$PR_URL"
      env:
        PR_URL: ${{github.event.pull_request.html_url}}
        GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}

What changed

1. Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. Each Linux x64 job moves to the Latchkey size matching its vCPU count, latchkey-small for a standard 2 vCPU runner; macOS, Windows and arm64 jobs stay as written.
2. Add a job timeout so a hung step cannot burn hours of runner time.

This workflow runs 1 job per trigger. It runs on a standard GitHub-hosted Linux x64 runner, which in a private repository bills $0.006 a minute against $0.0025 on latchkey-small, 58% lower; in a public repository like this one it is free. Estimate the monthly difference with your own run counts.

Actions used in this workflow

• dependabot/fetch-metadata

Frequently asked questions

References

• GitHub Actions documentation