CI workflow (PrismarineJS/mineflayer)

The CI workflow from PrismarineJS/mineflayer, explained and optimized by Latchkey.

CI health: D - needs work

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Source: PrismarineJS/mineflayer.github/workflows/ci.ymlLicense MITView source

What it does

This is the CI workflow from the PrismarineJS/mineflayer 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: CI

on:
  push:
    branches:
      - master
  pull_request:

jobs:
  Lint:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2
    - name: Use Node.js 22.x
      uses: actions/setup-node@v1.4.4
      with:
        node-version: 24
    - run: npm i && npm run lint
  
  PrepareSupportedVersions:
    runs-on: ubuntu-latest
    outputs:
      matrix: ${{ steps.set-matrix.outputs.matrix }}

    steps:
    - uses: actions/checkout@v2
    - name: Use Node.js 22.x
      uses: actions/setup-node@v1.4.4
      with:
        node-version: 24
    - id: set-matrix
      run: |
        node -e "
          const v = require('./lib/version').testedVersions;
          const groups = [];
          const SIZE = 4;
          for (let i = 0; i < v.length; i += SIZE) {
            groups.push({ versions: v.slice(i, i + SIZE).join(' ') });
          }
          console.log('matrix='+JSON.stringify({'include': groups}))
        " >> $GITHUB_OUTPUT

  MinecraftServer:
    needs: PrepareSupportedVersions
    runs-on: ubuntu-latest
    name: MC ${{ matrix.versions }}
    strategy:
      matrix: ${{ fromJson(needs.PrepareSupportedVersions.outputs.matrix) }}
      fail-fast: false

    steps:
      - uses: actions/checkout@v2
      - name: Use Node.js 22.x
        uses: actions/setup-node@v1.4.4
        with:
          node-version: 24
      - name: Setup Java JDK
        uses: actions/setup-java@v1.4.3
        with:
          java-version: 21
          java-package: jre
      - name: Install Dependencies
        run: npm install

      - name: Start Tests
        run: |
          exit_code=0
          pids=""
          for v in ${{ matrix.versions }}; do
            npm run mocha_test -- --retries 3 -g "${v}v" > "test-${v}.log" 2>&1 &
            pids="$pids $!"
          done
          for pid in $pids; do
            wait $pid || exit_code=$?
          done
          # Print passing versions first, then failing versions last
          for v in ${{ matrix.versions }}; do
            if ! grep -q "failing" "test-${v}.log"; then
              echo ""
              echo "=========================================="
              echo "  Results for Minecraft ${v}"
              echo "=========================================="
              cat "test-${v}.log"
            fi
          done
          for v in ${{ matrix.versions }}; do
            if grep -q "failing" "test-${v}.log"; then
              echo ""
              echo "=========================================="
              echo "  FAILED: Minecraft ${v}"
              echo "=========================================="
              cat "test-${v}.log"
            fi
          done
          exit $exit_code

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: CI
 
on:
  push:
    branches:
      - master
  pull_request:
 
concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true
 
jobs:
  Lint:
    timeout-minutes: 30
    runs-on: latchkey-small
 
    steps:
    - uses: actions/checkout@v2
    - name: Use Node.js 22.x
      uses: actions/setup-node@v1.4.4
      with:
        cache: 'npm'
        node-version: 24
    - run: npm i && npm run lint
  
  PrepareSupportedVersions:
    timeout-minutes: 30
    runs-on: latchkey-small
    outputs:
      matrix: ${{ steps.set-matrix.outputs.matrix }}
 
    steps:
    - uses: actions/checkout@v2
    - name: Use Node.js 22.x
      uses: actions/setup-node@v1.4.4
      with:
        cache: 'npm'
        node-version: 24
    - id: set-matrix
      run: |
        node -e "
          const v = require('./lib/version').testedVersions;
          const groups = [];
          const SIZE = 4;
          for (let i = 0; i < v.length; i += SIZE) {
            groups.push({ versions: v.slice(i, i + SIZE).join(' ') });
          }
          console.log('matrix='+JSON.stringify({'include': groups}))
        " >> $GITHUB_OUTPUT
 
  MinecraftServer:
    timeout-minutes: 30
    needs: PrepareSupportedVersions
    runs-on: latchkey-small
    name: MC ${{ matrix.versions }}
    strategy:
      matrix: ${{ fromJson(needs.PrepareSupportedVersions.outputs.matrix) }}
      fail-fast: false
 
    steps:
      - uses: actions/checkout@v2
      - name: Use Node.js 22.x
        uses: actions/setup-node@v1.4.4
        with:
          cache: 'npm'
          node-version: 24
      - name: Setup Java JDK
        uses: actions/setup-java@v1.4.3
        with:
          java-version: 21
          java-package: jre
      - name: Install Dependencies
        run: npm install
 
      - name: Start Tests
        run: |
          exit_code=0
          pids=""
          for v in ${{ matrix.versions }}; do
            npm run mocha_test -- --retries 3 -g "${v}v" > "test-${v}.log" 2>&1 &
            pids="$pids $!"
          done
          for pid in $pids; do
            wait $pid || exit_code=$?
          done
          # Print passing versions first, then failing versions last
          for v in ${{ matrix.versions }}; do
            if ! grep -q "failing" "test-${v}.log"; then
              echo ""
              echo "=========================================="
              echo "  Results for Minecraft ${v}"
              echo "=========================================="
              cat "test-${v}.log"
            fi
          done
          for v in ${{ matrix.versions }}; do
            if grep -q "failing" "test-${v}.log"; then
              echo ""
              echo "=========================================="
              echo "  FAILED: Minecraft ${v}"
              echo "=========================================="
              cat "test-${v}.log"
            fi
          done
          exit $exit_code

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

This workflow runs 3 jobs 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/setup-java