github-actions

GitHub Actions CI/CD Skill

Workflow File Location

All workflows live in .github/workflows/ as YAML files.

---

Step 1: Core Syntax

# .github/workflows/ci.yml
name: CI

on:
  push:
    branches: [main, develop]
  pull_request:
    branches: [main]

jobs:
  test:
    name: Test
    runs-on: ubuntu-latest  # or: ubuntu-22.04, windows-latest, macos-latest

    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '20'
          cache: 'npm'

      - name: Install dependencies
        run: npm ci

      - name: Run lint
        run: npm run lint

      - name: Run tests
        run: npm test -- --coverage

---

Step 2: Language-Specific Setup

Python

    - name: Set up Python
      uses: actions/setup-python@v5
      with:
        python-version: '3.12'
        cache: 'pip'

    - name: Install dependencies
      run: pip install -r requirements.txt -r requirements-dev.txt

    - name: Lint with ruff
      run: ruff check .

    - name: Type check with mypy
      run: mypy .

    - name: Run tests
      run: pytest --cov=. --cov-report=xml

    - name: Upload coverage
      uses: codecov/codecov-action@v4
      with:
        token: ${{ secrets.CODECOV_TOKEN }}

Go

    - name: Set up Go
      uses: actions/setup-go@v5
      with:
        go-version: '1.22'
        cache: true

    - name: Download dependencies
      run: go mod download

    - name: Run vet
      run: go vet ./...

    - name: Run tests
      run: go test -race -coverprofile=coverage.out ./...

---

Step 3: Matrix Builds

Test across multiple versions simultaneously:

jobs:
  test:
    strategy:
      fail-fast: false  # don't cancel others if one fails
      matrix:
        node-version: ['18', '20', '22']
        os: [ubuntu-latest, windows-latest]

    runs-on: ${{ matrix.os }}

    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}
      - run: npm ci
      - run: npm test