DevTools workflow (GoogleChrome/lighthouse)

The DevTools workflow from GoogleChrome/lighthouse, explained and optimized by Latchkey.

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Source: GoogleChrome/lighthouse.github/workflows/devtools.ymlLicense Apache-2.0View source

What it does

This is the DevTools workflow from the GoogleChrome/lighthouse 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

workflow (.yml)

name: DevTools

on:
  push:
    branches: [main]
  pull_request: # run on all PRs, not just PRs to a particular branch

env:
  DEPOT_TOOLS_PATH: ${{ github.workspace }}/depot-tools
  DEVTOOLS_PATH: ${{ github.workspace }}/devtools-frontend
  PUPPETEER_SKIP_DOWNLOAD: 1

jobs:
  build:
    runs-on: ubuntu-latest
    env:
      FORCE_COLOR: true

    steps:
    - name: Set $PATH
      run: echo "$DEPOT_TOOLS_PATH" >> $GITHUB_PATH

    - name: git clone
      uses: actions/checkout@v4
      with:
        path: lighthouse

    - name: Use Node.js 22.19
      uses: actions/setup-node@v4
      with:
        node-version: '22.19'

    - name: Generate cache hash
      run: bash $GITHUB_WORKSPACE/lighthouse/.github/scripts/generate-devtools-hash.sh > cdt-test-hash.txt
    - name: Set week of the year
      run: echo "WEEK_OF_THE_YEAR=$(date +%V)" >> $GITHUB_ENV
    # Caches are invalidated at least once a week, so that's the max time between testing
    # with the latest dependencies. Any commit to the DevTools repo touching Lighthouse
    # code will invalidate the cache sooner.
    - name: Cache depot tools and devtools
      id: devtools-cache
      uses: actions/cache@v3
      with:
        path: |
          ${{ env.DEPOT_TOOLS_PATH }}
          ${{ env.DEVTOOLS_PATH }}
          ${{ github.workspace }}/.gclient
          ${{ github.workspace }}/.gclient_entries
        # This hash key changes:
        # 1) every monday (so invalidates once a week)
        # 2) every commit to CDT touching files important to Lighthouse web tests
        # 3) every change to file in Lighthouse repo important to running these tests.
        #
        # The number is how many times this hash key was manually updated to break the cache.
        key: ${{ runner.os }}-15-${{ env.WEEK_OF_THE_YEAR }}-${{ hashFiles('cdt-test-hash.txt') }}
        restore-keys: ${{ runner.os }}-15
    - name: Set GHA_DEVTOOLS_CACHE_HIT
      if: steps.devtools-cache.outputs.cache-hit == 'true'
      run: echo "GHA_DEVTOOLS_CACHE_HIT=1" >> $GITHUB_ENV

    - run: yarn --frozen-lockfile --network-timeout 1000000
      working-directory: ${{ github.workspace }}/lighthouse

    - name: Download depot tools
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/download-depot-tools.sh
    - name: Download DevTools Frontend
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/download-devtools.sh

    - name: Roll Lighthouse + build DevTools
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/roll-devtools.sh

    - name: Cache build artifacts
      id: devtools-build-artifacts
      uses: actions/cache@v3
      with:
        path: |
          ${{ env.DEVTOOLS_PATH }}
          ${{ github.workspace }}/.gclient
          ${{ github.workspace }}/.gclient_entries
        key: devtools-build-artifacts-${{ github.run_id }}

  e2e:
    needs: [build]
    runs-on: ubuntu-latest
    env:
      FORCE_COLOR: true

    steps:
    - name: git clone
      uses: actions/checkout@v4
      with:
        path: lighthouse

    - name: Use Node.js 22.19
      uses: actions/setup-node@v4
      with:
        node-version: '22.19'

    - run: yarn --frozen-lockfile --network-timeout 1000000
      working-directory: ${{ github.workspace }}/lighthouse

    - name: Set $PATH
      run: echo "$DEPOT_TOOLS_PATH" >> $GITHUB_PATH
    # For vpython.
    - name: Download depot tools
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/download-depot-tools.sh

    # Since Ubuntu 23, dev builds of Chromium need this.
    # https://chromium.googlesource.com/chromium/src/+/main/docs/security/apparmor-userns-restrictions.md
    - run: sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0

    - name: Load build artifacts
      id: devtools-build-artifacts
      uses: actions/cache@v3
      with:
        path: |
          ${{ env.DEVTOOLS_PATH }}
          ${{ github.workspace }}/.gclient
          ${{ github.workspace }}/.gclient_entries
        key: devtools-build-artifacts-${{ github.run_id }}

    - name: Run e2e tests
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/run-e2e-tests.sh

  smoke:
    needs: [build]
    strategy:
      matrix:
        smoke-test-shard: [1, 2, 3]
      # e.g. if set 1 fails, continue with set 2 anyway
      fail-fast: false
    runs-on: ubuntu-latest
    env:
      CHROME_PATH: ${{ github.workspace }}/lighthouse/.tmp/chrome-tot/chrome
      FORCE_COLOR: true
    name: DevTools smoke ${{ matrix.smoke-test-shard }}/${{ strategy.job-total }}

    steps:
    - name: git clone
      uses: actions/checkout@v4
      with:
        path: lighthouse

    - name: Use Node.js 22.19
      uses: actions/setup-node@v4
      with:
        node-version: '22.19'

    - name: Load build artifacts
      id: devtools-build-artifacts
      uses: actions/cache@v3
      with:
        path: |
          ${{ env.DEVTOOLS_PATH }}
          ${{ github.workspace }}/.gclient
          ${{ github.workspace }}/.gclient_entries
        key: devtools-build-artifacts-${{ github.run_id }}

    - run: yarn --frozen-lockfile --network-timeout 1000000
      working-directory: ${{ github.workspace }}/lighthouse

    # This is only done because the import of `parseChromeFlags` in pptr-run-devtool.js triggers imports that eventually
    # fail because of how report-assets.js reads generated files.
    - run: yarn build-report
      working-directory: ${{ github.workspace }}/lighthouse

    # Since Ubuntu 23, dev builds of Chromium need this.
    # https://chromium.googlesource.com/chromium/src/+/main/docs/security/apparmor-userns-restrictions.md
    - run: sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0

    - name: Install Chrome ToT
      run: bash ${{ github.workspace }}/lighthouse/core/scripts/download-chrome.sh

    - run: mkdir latest-run
      working-directory: ${{ github.workspace }}/lighthouse
    - name: yarn smoke --runner devtools
      run: yarn smoke --runner devtools --shard=${{ matrix.smoke-test-shard }}/${{ strategy.job-total }} --jobs=3 --retries=2 --debug
      working-directory: ${{ github.workspace }}/lighthouse

    - name: Upload failures
      if: failure()
      uses: actions/upload-artifact@v7
      with:
        name: Smokehouse (devtools smoke)
        path: ${{ github.workspace }}/lighthouse/.tmp/smokehouse-failures/

The same workflow, on Latchkey

Estimated ~20% faster on cache hits, plus fewer wasted runs and a safer supply chain. Added and changed lines are highlighted.

name: DevTools
 
on:
  push:
    branches: [main]
  pull_request: # run on all PRs, not just PRs to a particular branch
 
env:
  DEPOT_TOOLS_PATH: ${{ github.workspace }}/depot-tools
  DEVTOOLS_PATH: ${{ github.workspace }}/devtools-frontend
  PUPPETEER_SKIP_DOWNLOAD: 1
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  build:
    timeout-minutes: 30
    runs-on: latchkey-small
    env:
      FORCE_COLOR: true
 
    steps:
    - name: Set $PATH
      run: echo "$DEPOT_TOOLS_PATH" >> $GITHUB_PATH
 
    - name: git clone
      uses: actions/checkout@v4
      with:
        path: lighthouse
 
    - name: Use Node.js 22.19
      uses: actions/setup-node@v4
      with:
        cache: 'npm'
        node-version: '22.19'
 
    - name: Generate cache hash
      run: bash $GITHUB_WORKSPACE/lighthouse/.github/scripts/generate-devtools-hash.sh > cdt-test-hash.txt
    - name: Set week of the year
      run: echo "WEEK_OF_THE_YEAR=$(date +%V)" >> $GITHUB_ENV
    # Caches are invalidated at least once a week, so that's the max time between testing
    # with the latest dependencies. Any commit to the DevTools repo touching Lighthouse
    # code will invalidate the cache sooner.
    - name: Cache depot tools and devtools
      id: devtools-cache
      uses: actions/cache@v3
      with:
        path: |
          ${{ env.DEPOT_TOOLS_PATH }}
          ${{ env.DEVTOOLS_PATH }}
          ${{ github.workspace }}/.gclient
          ${{ github.workspace }}/.gclient_entries
        # This hash key changes:
        # 1) every monday (so invalidates once a week)
        # 2) every commit to CDT touching files important to Lighthouse web tests
        # 3) every change to file in Lighthouse repo important to running these tests.
        #
        # The number is how many times this hash key was manually updated to break the cache.
        key: ${{ runner.os }}-15-${{ env.WEEK_OF_THE_YEAR }}-${{ hashFiles('cdt-test-hash.txt') }}
        restore-keys: ${{ runner.os }}-15
    - name: Set GHA_DEVTOOLS_CACHE_HIT
      if: steps.devtools-cache.outputs.cache-hit == 'true'
      run: echo "GHA_DEVTOOLS_CACHE_HIT=1" >> $GITHUB_ENV
 
    - run: yarn --frozen-lockfile --network-timeout 1000000
      working-directory: ${{ github.workspace }}/lighthouse
 
    - name: Download depot tools
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/download-depot-tools.sh
    - name: Download DevTools Frontend
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/download-devtools.sh
 
    - name: Roll Lighthouse + build DevTools
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/roll-devtools.sh
 
    - name: Cache build artifacts
      id: devtools-build-artifacts
      uses: actions/cache@v3
      with:
        path: |
          ${{ env.DEVTOOLS_PATH }}
          ${{ github.workspace }}/.gclient
          ${{ github.workspace }}/.gclient_entries
        key: devtools-build-artifacts-${{ github.run_id }}
 
  e2e:
    timeout-minutes: 30
    needs: [build]
    runs-on: latchkey-small
    env:
      FORCE_COLOR: true
 
    steps:
    - name: git clone
      uses: actions/checkout@v4
      with:
        path: lighthouse
 
    - name: Use Node.js 22.19
      uses: actions/setup-node@v4
      with:
        cache: 'npm'
        node-version: '22.19'
 
    - run: yarn --frozen-lockfile --network-timeout 1000000
      working-directory: ${{ github.workspace }}/lighthouse
 
    - name: Set $PATH
      run: echo "$DEPOT_TOOLS_PATH" >> $GITHUB_PATH
    # For vpython.
    - name: Download depot tools
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/download-depot-tools.sh
 
    # Since Ubuntu 23, dev builds of Chromium need this.
    # https://chromium.googlesource.com/chromium/src/+/main/docs/security/apparmor-userns-restrictions.md
    - run: sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
 
    - name: Load build artifacts
      id: devtools-build-artifacts
      uses: actions/cache@v3
      with:
        path: |
          ${{ env.DEVTOOLS_PATH }}
          ${{ github.workspace }}/.gclient
          ${{ github.workspace }}/.gclient_entries
        key: devtools-build-artifacts-${{ github.run_id }}
 
    - name: Run e2e tests
      run: bash $GITHUB_WORKSPACE/lighthouse/core/test/devtools-tests/run-e2e-tests.sh
 
  smoke:
    timeout-minutes: 30
    needs: [build]
    strategy:
      matrix:
        smoke-test-shard: [1, 2, 3]
      # e.g. if set 1 fails, continue with set 2 anyway
      fail-fast: false
    runs-on: latchkey-small
    env:
      CHROME_PATH: ${{ github.workspace }}/lighthouse/.tmp/chrome-tot/chrome
      FORCE_COLOR: true
    name: DevTools smoke ${{ matrix.smoke-test-shard }}/${{ strategy.job-total }}
 
    steps:
    - name: git clone
      uses: actions/checkout@v4
      with:
        path: lighthouse
 
    - name: Use Node.js 22.19
      uses: actions/setup-node@v4
      with:
        cache: 'npm'
        node-version: '22.19'
 
    - name: Load build artifacts
      id: devtools-build-artifacts
      uses: actions/cache@v3
      with:
        path: |
          ${{ env.DEVTOOLS_PATH }}
          ${{ github.workspace }}/.gclient
          ${{ github.workspace }}/.gclient_entries
        key: devtools-build-artifacts-${{ github.run_id }}
 
    - run: yarn --frozen-lockfile --network-timeout 1000000
      working-directory: ${{ github.workspace }}/lighthouse
 
    # This is only done because the import of `parseChromeFlags` in pptr-run-devtool.js triggers imports that eventually
    # fail because of how report-assets.js reads generated files.
    - run: yarn build-report
      working-directory: ${{ github.workspace }}/lighthouse
 
    # Since Ubuntu 23, dev builds of Chromium need this.
    # https://chromium.googlesource.com/chromium/src/+/main/docs/security/apparmor-userns-restrictions.md
    - run: sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
 
    - name: Install Chrome ToT
      run: bash ${{ github.workspace }}/lighthouse/core/scripts/download-chrome.sh
 
    - run: mkdir latest-run
      working-directory: ${{ github.workspace }}/lighthouse
    - name: yarn smoke --runner devtools
      run: yarn smoke --runner devtools --shard=${{ matrix.smoke-test-shard }}/${{ strategy.job-total }} --jobs=3 --retries=2 --debug
      working-directory: ${{ github.workspace }}/lighthouse
 
    - name: Upload failures
      if: failure()
      uses: actions/upload-artifact@v7
      with:
        name: Smokehouse (devtools smoke)
        path: ${{ github.workspace }}/lighthouse/.tmp/smokehouse-failures/

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.
Cancel superseded runs when a branch or PR gets a newer push.
Cache dependency installs on the setup step so they are served from cache.
Add a job timeout so a hung step cannot burn hours of runner time.

What Latchkey heals here

This workflow has steps that commonly fail on transient issues (network, registries, flaky browsers). On Latchkey managed runners they are detected, retried, and self-healed instead of failing your build:

Dependency installs
End-to-end and browser tests

This workflow runs 3 jobs (5 with the matrix expanded) per trigger. On Latchkey the same minutes cost up to 58% less than GitHub-hosted, with zero queue time.

Actions used in this workflow

actions/checkout actions/setup-node actions/cache actions/upload-artifact