Chapter 3: CI/CD with GitHub Actions

Introduction

CI/CD (Continuous Integration / Continuous Deployment) automates the build, tests, and deployment. No more manual deployment, fewer human errors.

🎯 Chapter Objectives

By the end of this chapter, you will know how to:

✅ Understand CI/CD
✅ Create GitHub Actions workflows
✅ Automate tests and build
✅ Publish Docker images
✅ Deploy automatically

1. Introduction to CI/CD

Continuous Integration (CI)

Push on GitHub
      ↓
┌─────────────────┐
│  GitHub Actions │
│    Workflow     │
├─────────────────┤
│ 1. Checkout     │
│ 2. Setup Java   │
│ 3. Build        │
│ 4. Tests        │
│ 5. Analyze      │
└─────────────────┘
      ↓
   ✅ or ❌

Continuous Deployment (CD)

Successful CI
    ↓
┌─────────────────┐
│ 1. Build Docker │
│ 2. Push Registry│
│ 3. Deploy       │
└─────────────────┘
    ↓
🚀 In Production

2. GitHub Actions Basics

Structure

.github/
└── workflows/
    ├── ci.yml          # Tests on each push
    ├── release.yml     # Publish on tags
    └── deploy.yml      # Deployment

Basic Syntax

name: CI Pipeline

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

jobs:
  build:
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
      
      - name: Setup Java
        uses: actions/setup-java@v4
        with:
          distribution: 'temurin'
          java-version: '17'
      
      - name: Build
        run: mvn clean package

3. Complete CI Workflow

.github/workflows/ci.yml

name: CI Pipeline

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

jobs:
  test:
    name: Build and Test
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
      
      - name: Set up JDK 17
        uses: actions/setup-java@v4
        with:
          distribution: 'temurin'
          java-version: '17'
          cache: 'maven'
      
      - name: Build with Maven
        run: mvn clean compile
      
      - name: Run Tests
        run: mvn test
      
      - name: Upload Test Results
        uses: actions/upload-artifact@v4
        if: always()
        with:
          name: test-results
          path: target/surefire-reports/
      
      - name: Generate Coverage Report
        run: mvn jacoco:report
      
      - name: Upload Coverage to Codecov
        uses: codecov/codecov-action@v3
        with:
          files: target/site/jacoco/jacoco.xml

  package:
    name: Package Application
    runs-on: ubuntu-latest
    needs: test
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
      
      - name: Set up JDK 17
        uses: actions/setup-java@v4
        with:
          distribution: 'temurin'
          java-version: '17'
          cache: 'maven'
      
      - name: Package JAR
        run: mvn package -DskipTests
      
      - name: Upload JAR
        uses: actions/upload-artifact@v4
        with:
          name: app-jar
          path: target/*.jar

4. Docker Workflow

.github/workflows/docker.yml

name: Docker Build and Push

on:
  push:
    branches: [main]
    tags: ['v*']

env:
  REGISTRY: docker.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  build-and-push:
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
      
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
      
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      
      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=ref,event=branch
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=sha
      
      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

Configure Secrets

In GitHub Repository → Settings → Secrets → Actions:

DOCKERHUB_USERNAME=your-username
DOCKERHUB_TOKEN=your-token

5. Deployment Workflow

Deploy on Railway

name: Deploy to Railway

on:
  push:
    branches: [main]

jobs:
  deploy:
    runs-on: ubuntu-latest
    needs: [test, build-docker]
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
      
      - name: Install Railway CLI
        run: npm i -g @railway/cli
      
      - name: Deploy to Railway
        run: railway up
        env:
          RAILWAY_TOKEN: ${{ secrets.RAILWAY_TOKEN }}

Deploy on Heroku

name: Deploy to Heroku

on:
  push:
    branches: [main]

jobs:
  deploy:
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
      
      - name: Deploy to Heroku
        uses: akhileshns/heroku-deploy@v3.12.14
        with:
          heroku_api_key: ${{ secrets.HEROKU_API_KEY }}
          heroku_app_name: ${{ secrets.HEROKU_APP_NAME }}
          heroku_email: ${{ secrets.HEROKU_EMAIL }}
          usedocker: true

6. Complete CI/CD Workflow

.github/workflows/main.yml

name: CI/CD Pipeline

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

env:
  REGISTRY: docker.io
  IMAGE_NAME: myuser/myapp

jobs:
  # ===== JOB 1: Test =====
  test:
    name: Test
    runs-on: ubuntu-latest
    
    services:
      postgres:
        image: postgres:15
        env:
          POSTGRES_DB: testdb
          POSTGRES_USER: test
          POSTGRES_PASSWORD: test
        ports:
          - 5432:5432
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
    
    steps:
      - uses: actions/checkout@v4
      
      - name: Set up JDK 17
        uses: actions/setup-java@v4
        with:
          distribution: 'temurin'
          java-version: '17'
          cache: 'maven'
      
      - name: Run Tests
        run: mvn test
        env:
          SPRING_DATASOURCE_URL: jdbc:postgresql://localhost:5432/testdb
          SPRING_DATASOURCE_USERNAME: test
          SPRING_DATASOURCE_PASSWORD: test

  # ===== JOB 2: Build Docker =====
  build:
    name: Build Docker
    runs-on: ubuntu-latest
    needs: test
    if: github.event_name == 'push'
    
    outputs:
      image-tag: ${{ steps.meta.outputs.tags }}
    
    steps:
      - uses: actions/checkout@v4
      
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
      
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      
      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.IMAGE_NAME }}
      
      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

  # ===== JOB 3: Deploy =====
  deploy:
    name: Deploy to Production
    runs-on: ubuntu-latest
    needs: build
    if: github.ref == 'refs/heads/main'
    environment: production
    
    steps:
      - uses: actions/checkout@v4
      
      - name: Deploy to Railway
        run: |
          npm i -g @railway/cli
          railway up
        env:
          RAILWAY_TOKEN: ${{ secrets.RAILWAY_TOKEN }}

7. Best Practices

Maven Cache

- uses: actions/setup-java@v4
  with:
    distribution: 'temurin'
    java-version: '17'
    cache: 'maven'  # ← Enables automatic cache

Parallelization

jobs:
  test-unit:
    runs-on: ubuntu-latest
    steps: [...]
  
  test-integration:
    runs-on: ubuntu-latest
    steps: [...]
  
  build:
    needs: [test-unit, test-integration]  # Waits for both
    steps: [...]

Protected Environments

deploy:
  environment: production  # Requires approval

Version Matrix

jobs:
  test:
    strategy:
      matrix:
        java: [17, 21]
        os: [ubuntu-latest, windows-latest]
    
    runs-on: ${{ matrix.os }}
    
    steps:
      - uses: actions/setup-java@v4
        with:
          java-version: ${{ matrix.java }}

8. Summary

Workflow Structure

.github/workflows/
├── ci.yml       # Tests on PR and push
├── docker.yml   # Build and push image
└── deploy.yml   # Production deployment

Required Secrets

DOCKERHUB_USERNAME
DOCKERHUB_TOKEN
RAILWAY_TOKEN (or HEROKU_API_KEY)

Minimal Workflow

name: CI
on: [push, pull_request]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with:
          distribution: 'temurin'
          java-version: '17'
          cache: 'maven'
      - run: mvn test

🎯 Next Step

CI/CD pipeline ready! Let's explore cloud deployment options.

➡️ Chapter 4: Cloud Deployment

⬅️ Back to Module 12

Introduction​

🎯 Chapter Objectives​

1. Introduction to CI/CD​

Continuous Integration (CI)​

Continuous Deployment (CD)​

2. GitHub Actions Basics​

Structure​

Basic Syntax​

3. Complete CI Workflow​

.github/workflows/ci.yml​

4. Docker Workflow​

.github/workflows/docker.yml​

Configure Secrets​

5. Deployment Workflow​

Deploy on Railway​

Deploy on Heroku​

6. Complete CI/CD Workflow​

.github/workflows/main.yml​

7. Best Practices​

Maven Cache​

Parallelization​

Protected Environments​

Version Matrix​

8. Summary​

Workflow Structure​

Required Secrets​

Minimal Workflow​

🎯 Next Step​