GitHub Actions CI/CD Complete Pipeline Guide

# GitHub Actions CI/CD Complete Guide

Build robust CI/CD pipelines with GitHub Actions for automated testing, building, and deployment of modern applications.

## Complete Next.js Pipeline

### Full CI/CD Workflow

```yaml
# .github/workflows/ci-cd.yml
name: CI/CD Pipeline

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

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

env:
  NODE_VERSION: "20"
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  lint:
    name: Lint & Type Check
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: ${{ env.NODE_VERSION }}
          cache: "npm"

      - name: Install dependencies
        run: npm ci

      - name: Run ESLint
        run: npm run lint

      - name: Run Type Check
        run: npm run type-check

  test:
    name: Test
    runs-on: ubuntu-latest
    needs: lint
    services:
      postgres:
        image: postgres:15
        env:
          POSTGRES_USER: test
          POSTGRES_PASSWORD: test
          POSTGRES_DB: testdb
        ports:
          - 5432:5432
        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5

    steps:
      - uses: actions/checkout@v4

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: ${{ env.NODE_VERSION }}
          cache: "npm"

      - name: Install dependencies
        run: npm ci

      - name: Run migrations
        run: npx prisma migrate deploy
        env:
          DATABASE_URL: postgresql://test:test@localhost:5432/testdb

      - name: Run tests
        run: npm run test:ci
        env:
          DATABASE_URL: postgresql://test:test@localhost:5432/testdb

      - name: Upload coverage
        uses: codecov/codecov-action@v3
        with:
          token: ${{ secrets.CODECOV_TOKEN }}
          files: ./coverage/lcov.info

  build:
    name: Build
    runs-on: ubuntu-latest
    needs: [lint, test]
    outputs:
      version: ${{ steps.version.outputs.version }}
    steps:
      - uses: actions/checkout@v4

      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: ${{ env.NODE_VERSION }}
          cache: "npm"

      - name: Install dependencies
        run: npm ci

      - name: Build application
        run: npm run build
        env:
          NEXT_PUBLIC_API_URL: ${{ vars.NEXT_PUBLIC_API_URL }}

      - name: Generate version
        id: version
        run: echo "version=$(date +%Y%m%d%H%M%S)-${GITHUB_SHA::7}" >> $GITHUB_OUTPUT

      - name: Upload build artifact
        uses: actions/upload-artifact@v4
        with:
          name: build-${{ steps.version.outputs.version }}
          path: .next
          retention-days: 7

  docker:
    name: Build Docker Image
    runs-on: ubuntu-latest
    needs: build
    if: github.ref == 'refs/heads/main'
    permissions:
      contents: read
      packages: write
    steps:
      - uses: actions/checkout@v4

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Login to Container Registry
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: |
            type=sha,prefix=
            type=raw,value=latest

      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          build-args: |
            NEXT_PUBLIC_API_URL=${{ vars.NEXT_PUBLIC_API_URL }}

  deploy-staging:
    name: Deploy to Staging
    runs-on: ubuntu-latest
    needs: docker
    environment:
      name: staging
      url: https://staging.example.com
    steps:
      - name: Deploy to staging
        uses: appleboy/ssh-action@v1.0.0
        with:
          host: ${{ secrets.STAGING_HOST }}
          username: ${{ secrets.SSH_USER }}
          key: ${{ secrets.SSH_PRIVATE_KEY }}
          script: |
            docker pull ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
            docker service update --image ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest app

  deploy-production:
    name: Deploy to Production
    runs-on: ubuntu-latest
    needs: deploy-staging
    environment:
      name: production
      url: https://example.com
    steps:
      - name: Deploy to production
        uses: appleboy/ssh-action@v1.0.0
        with:
          host: ${{ secrets.PROD_HOST }}
          username: ${{ secrets.SSH_USER }}
          key: ${{ secrets.SSH_PRIVATE_KEY }}
          script: |
            docker pull ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
            docker service update --image ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest app
```

## Matrix Builds

### Cross-Platform Testing

```yaml
jobs:
  test:
    strategy:
      fail-fast: false
      matrix:
        os: [ubuntu-latest, macos-latest, windows-latest]
        node: [18, 20, 22]
        exclude:
          - os: windows-latest
            node: 18
    runs-on: ${{ matrix.os }}
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node }}
      - run: npm ci
      - run: npm test
```

## Reusable Workflows

### Shared Workflow

```yaml
# .github/workflows/reusable-deploy.yml
name: Reusable Deploy

on:
  workflow_call:
    inputs:
      environment:
        required: true
        type: string
      image_tag:
        required: true
        type: string
    secrets:
      SSH_KEY:
        required: true
      HOST:
        required: true

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment: ${{ inputs.environment }}
    steps:
      - name: Deploy
        uses: appleboy/ssh-action@v1.0.0
        with:
          host: ${{ secrets.HOST }}
          username: deploy
          key: ${{ secrets.SSH_KEY }}
          script: |
            docker pull ${{ inputs.image_tag }}
            docker-compose up -d
```

### Calling Reusable Workflow

```yaml
# .github/workflows/deploy.yml
jobs:
  deploy-staging:
    uses: ./.github/workflows/reusable-deploy.yml
    with:
      environment: staging
      image_tag: ghcr.io/org/app:${{ github.sha }}
    secrets:
      SSH_KEY: ${{ secrets.STAGING_SSH_KEY }}
      HOST: ${{ secrets.STAGING_HOST }}
```

## Composite Actions

```yaml
# .github/actions/setup-project/action.yml
name: Setup Project
description: Setup Node.js and install dependencies

inputs:
  node-version:
    description: Node.js version
    default: "20"

runs:
  using: composite
  steps:
    - uses: actions/setup-node@v4
      with:
        node-version: ${{ inputs.node-version }}
        cache: npm

    - name: Install dependencies
      shell: bash
      run: npm ci

    - name: Generate Prisma client
      shell: bash
      run: npx prisma generate
```

## Advanced Caching

```yaml
- name: Cache Next.js build
  uses: actions/cache@v4
  with:
    path: |
      ~/.npm
      ${{ github.workspace }}/.next/cache
    key: ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json') }}-${{ hashFiles('**/*.ts', '**/*.tsx') }}
    restore-keys: |
      ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json') }}-
      ${{ runner.os }}-nextjs-
```

This GitHub Actions guide provides complete CI/CD pipeline patterns for testing, building, and deploying modern applications.