GitHub Actions

What are GitHub Actions?

GitHub Actions is a CI/CD platform that allows you to automate build, test, and deployment workflows directly from your GitHub repository.

Basic Workflow

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

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

jobs:
  build:
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
      
      - name: Setup Node.js
        uses: actions/setup-node@v3
        with:
          node-version: '18'
      
      - name: Install dependencies
        run: npm ci
      
      - name: Run tests
        run: npm test
      
      - name: Build
        run: npm run build

Multi-Stack Workflows

Angular

name: Angular CI/CD

on: [push, pull_request]

jobs:
  angular:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      
      - uses: actions/setup-node@v3
        with:
          node-version: '18'
          cache: 'npm'
      
      - run: npm ci
      - run: ng lint
      - run: ng test --watch=false --code-coverage
      - run: ng build --configuration production
      
      - name: Deploy to Firebase
        if: github.ref == 'refs/heads/main'
        run: |
          npm install -g firebase-tools
          firebase deploy --token ${{ secrets.FIREBASE_TOKEN }}

.NET

name: .NET CI/CD

on: [push, pull_request]

jobs:
  dotnet:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      
      - uses: actions/setup-dotnet@v3
        with:
          dotnet-version: '8.0.x'
      
      - run: dotnet restore
      - run: dotnet build --no-restore -c Release
      - run: dotnet test --no-build -c Release
      - run: dotnet publish -c Release -o ./publish
      
      - name: Deploy to Azure
        if: github.ref == 'refs/heads/main'
        uses: azure/webapps-deploy@v2
        with:
          app-name: my-dotnet-app
          publish-profile: ${{ secrets.AZURE_PUBLISH_PROFILE }}
          package: ./publish

Node.js with Databases

name: Node.js with Databases

on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    
    services:
      postgres:
        image: postgres:15
        env:
          POSTGRES_PASSWORD: postgres
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
      
      mongodb:
        image: mongo:6
        ports:
          - 27017:27017
      
      redis:
        image: redis:7
        ports:
          - 6379:6379
    
    steps:
      - uses: actions/checkout@v3
      
      - uses: actions/setup-node@v3
        with:
          node-version: '18'
      
      - run: npm ci
      
      - name: Run migrations
        run: npm run migrate
        env:
          DATABASE_URL: postgresql://postgres:postgres@localhost:5432/test
      
      - name: Run tests
        run: npm test
        env:
          DATABASE_URL: postgresql://postgres:postgres@localhost:5432/test
          MONGODB_URL: mongodb://localhost:27017/test
          REDIS_URL: redis://localhost:6379

Matrix Builds

name: Matrix Build

on: [push]

jobs:
  test:
    runs-on: ${{ matrix.os }}
    
    strategy:
      matrix:
        os: [ubuntu-latest, windows-latest, macos-latest]
        node: [16, 18, 20]
    
    steps:
      - uses: actions/checkout@v3
      
      - uses: actions/setup-node@v3
        with:
          node-version: ${{ matrix.node }}
      
      - run: npm ci
      - run: npm test

Caching

jobs:
  build:
    steps:
      - uses: actions/checkout@v3
      
      - uses: actions/cache@v3
        with:
          path: ~/.npm
          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
          restore-keys: |
            ${{ runner.os }}-node-
      
      - run: npm ci
      - run: npm test

Artifacts

jobs:
  build:
    steps:
      - run: npm run build
      
      - uses: actions/upload-artifact@v3
        with:
          name: dist
          path: dist/
  
  deploy:
    needs: build
    steps:
      - uses: actions/download-artifact@v3
        with:
          name: dist
      
      - run: ./deploy.sh

Secrets Management

jobs:
  deploy:
    steps:
      - name: Deploy
        env:
          API_KEY: ${{ secrets.API_KEY }}
          DATABASE_URL: ${{ secrets.DATABASE_URL }}
        run: ./deploy.sh

Reusable Workflows

# .github/workflows/reusable-test.yml
name: Reusable Test

on:
  workflow_call:
    inputs:
      node-version:
        required: true
        type: string

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3
        with:
          node-version: ${{ inputs.node-version }}
      - run: npm ci
      - run: npm test

# .github/workflows/main.yml
name: Main

on: [push]

jobs:
  test-node-18:
    uses: ./.github/workflows/reusable-test.yml
    with:
      node-version: '18'

Docker Build

name: Docker Build

on: [push]

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      
      - name: Login to Docker Hub
        uses: docker/login-action@v2
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}
      
      - name: Build and push
        uses: docker/build-push-action@v4
        with:
          context: .
          push: true
          tags: myapp:${{ github.sha }},myapp:latest

Interview Tips

• Explain GitHub Actions: CI/CD platform for GitHub
• Show workflows: Multi-stack examples
• Demonstrate services: Database integration
• Discuss matrix: Multiple OS/versions
• Mention caching: Speed optimization
• Show secrets: Secure credential management

Summary

GitHub Actions automates CI/CD workflows directly in GitHub repositories. Supports multi-stack applications including Angular, .NET, Node.js with databases. Use matrix builds for multiple environments. Implement caching for speed. Manage secrets securely. Integrate with Docker and cloud platforms.