Capítulo 3: CI/CD con GitHub Actions

Introducción

CI/CD (Integración Continua / Despliegue Continuo) automatiza el build, las pruebas y el despliegue. No más despliegue manual, menos errores humanos.

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🎯 Objetivos del Capítulo

Al final de este capítulo, usted sabrá:

1. ✅ Comprender CI/CD
2. ✅ Crear workflows de GitHub Actions
3. ✅ Automatizar pruebas y build
4. ✅ Publicar imágenes Docker
5. ✅ Desplegar automáticamente

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1. Introducción a CI/CD

Integración Continua (CI)

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

Despliegue Continuo (CD)

CI exitosa
    ↓
┌─────────────────┐
│ 1. Build Docker │
│ 2. Push Registry│
│ 3. Deploy       │
└─────────────────┘
    ↓
🚀 En Producción

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2. GitHub Actions Básico

Estructura

.github/
└── workflows/
    ├── ci.yml          # Pruebas en cada push
    ├── release.yml     # Publicación en tags
    └── deploy.yml      # Despliegue

Sintaxis Básica

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. Workflow CI Completo

.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. Workflow Docker

.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

Configurar los Secrets

En GitHub Repository → Settings → Secrets → Actions:

DOCKERHUB_USERNAME=su-usuario
DOCKERHUB_TOKEN=su-token

---

5. Workflow de Despliegue

Deploy en 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 en 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. Workflow Completo CI/CD

.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 }}

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7. Buenas Prácticas

Cache Maven

- uses: actions/setup-java@v4
  with:
    distribution: 'temurin'
    java-version: '17'
    cache: 'maven'  # ← Activa el cache automático

Paralelización

jobs:
  test-unit:
    runs-on: ubuntu-latest
    steps: [...]
  
  test-integration:
    runs-on: ubuntu-latest
    steps: [...]
  
  build:
    needs: [test-unit, test-integration]  # Espera ambos
    steps: [...]

Entornos Protegidos

deploy:
  environment: production  # Requiere aprobación

Matriz de Versiones

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 }}

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8. Resumen

Estructura de los Workflows

.github/workflows/
├── ci.yml       # Pruebas en PR y push
├── docker.yml   # Build y push de imagen
└── deploy.yml   # Despliegue a producción

Secrets Necesarios

DOCKERHUB_USERNAME
DOCKERHUB_TOKEN
RAILWAY_TOKEN (o HEROKU_API_KEY)

Workflow Mínimo

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

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🎯 Próximo Paso

¡Pipeline CI/CD listo! Veamos las opciones de despliegue en la nube.

➡️ Capítulo 4: Despliegue Cloud

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⬅️ Volver al Módulo 12