Dependabot auto-merge workflow (vkbottle/vkbottle)

The Dependabot auto-merge workflow from vkbottle/vkbottle, explained and optimized by Latchkey.

CI health: B - good

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Source: vkbottle/vkbottle.github/workflows/dependabot-automerge.ymlLicense MITView source

What it does

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

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

The workflow

workflow (.yml)

name: Dependabot auto-merge

on:
  workflow_run:
    workflows: ["Pull-request"]
    types:
      - completed

jobs:
  dependabot:
    runs-on: ubuntu-latest
    if: github.actor == 'dependabot[bot]' && github.event.workflow_run.conclusion == 'success'
    steps:
      - uses: asottile/workflows/.github/actions/fast-checkout@v1.11.0

      - name: Merge pull request
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PR_NUMBER: ${{ github.event.workflow_run.pull_requests[0].number }}
        run: |
          gh pr merge $PR_NUMBER --squash --delete-branch

The same workflow, on Latchkey

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

name: Dependabot auto-merge
 
on:
  workflow_run:
    workflows: ["Pull-request"]
    types:
      - completed
 
jobs:
  dependabot:
    timeout-minutes: 30
    runs-on: latchkey-small
    if: github.actor == 'dependabot[bot]' && github.event.workflow_run.conclusion == 'success'
    steps:
      - uses: asottile/workflows/.github/actions/fast-checkout@v1.11.0
 
      - name: Merge pull request
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PR_NUMBER: ${{ github.event.workflow_run.pull_requests[0].number }}
        run: |
          gh pr merge $PR_NUMBER --squash --delete-branch

What changed

Run on Latchkey managed runners with one line (runs-on), which apply the fixes below automatically and self-heal transient failures. This example uses latchkey-small; pick the runner size that fits the job.
Add a job timeout so a hung step cannot burn hours of runner time.

1 third-party action is referenced by a movable tag. Pin it to the commit SHA (Latchkey resolves and applies this automatically) so a repointed tag cannot change what runs.

This workflow runs 1 job per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.