Advanced GitHub Actions Workflows

# Advanced GitHub Actions Workflows for Google Antigravity

GitHub Actions enables powerful automation. This guide covers advanced workflow patterns optimized for Google Antigravity IDE and Gemini 3.

## CI/CD Pipeline

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

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

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

concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}

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: Type check
        run: npm run type-check

  test:
    name: Test (${{ matrix.shard }})
    runs-on: ubuntu-latest
    needs: lint
    strategy:
      fail-fast: false
      matrix:
        shard: [1, 2, 3, 4]
    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 tests
        run: npm test -- --shard=${{ matrix.shard }}/${{ strategy.job-total }}
        env:
          CI: true
      
      - name: Upload coverage
        uses: codecov/codecov-action@v4
        with:
          flags: unit-${{ matrix.shard }}

  e2e:
    name: E2E Tests
    runs-on: ubuntu-latest
    needs: lint
    services:
      postgres:
        image: postgres:15
        env:
          POSTGRES_USER: test
          POSTGRES_PASSWORD: test
          POSTGRES_DB: test
        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: Install Playwright browsers
        run: npx playwright install --with-deps chromium
      
      - name: Run E2E tests
        run: npm run test:e2e
        env:
          DATABASE_URL: postgresql://test:test@localhost:5432/test
      
      - name: Upload test artifacts
        if: failure()
        uses: actions/upload-artifact@v4
        with:
          name: playwright-report
          path: playwright-report/

  build:
    name: Build & Push
    runs-on: ubuntu-latest
    needs: [test, e2e]
    if: github.event_name == 'push' && github.ref == 'refs/heads/main'
    permissions:
      contents: read
      packages: write
    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 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=ref,event=branch
            type=semver,pattern={{version}}
      
      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          build-args: |
            NODE_VERSION=${{ env.NODE_VERSION }}

  deploy-staging:
    name: Deploy to Staging
    runs-on: ubuntu-latest
    needs: build
    environment:
      name: staging
      url: https://staging.example.com
    steps:
      - uses: actions/checkout@v4
      
      - name: Deploy to Kubernetes
        uses: azure/k8s-deploy@v4
        with:
          namespace: staging
          manifests: k8s/staging/
          images: ${{ needs.build.outputs.image-tag }}
```

## Reusable Workflow

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

on:
  workflow_call:
    inputs:
      environment:
        required: true
        type: string
      image-tag:
        required: true
        type: string
    secrets:
      KUBE_CONFIG:
        required: true

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment: ${{ inputs.environment }}
    steps:
      - uses: actions/checkout@v4
      
      - name: Setup kubectl
        uses: azure/setup-kubectl@v3
      
      - name: Configure kubeconfig
        run: |
          mkdir -p ~/.kube
          echo "${{ secrets.KUBE_CONFIG }}" | base64 -d > ~/.kube/config
      
      - name: Deploy
        run: |
          kubectl set image deployment/app app=${{ inputs.image-tag }} -n ${{ inputs.environment }}
          kubectl rollout status deployment/app -n ${{ inputs.environment }}
```

## Composite Action

```yaml
# .github/actions/setup-project/action.yml
name: Setup Project
description: Common setup steps for the project

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

runs:
  using: composite
  steps:
    - name: Setup Node.js
      uses: actions/setup-node@v4
      with:
        node-version: ${{ inputs.node-version }}
        cache: npm
    
    - name: Install dependencies
      shell: bash
      run: npm ci
    
    - name: Cache build
      uses: actions/cache@v4
      with:
        path: .next/cache
        key: ${{ runner.os }}-nextjs-${{ hashFiles('**/package-lock.json') }}
```

## Best Practices

1. **Concurrency**: Cancel redundant runs for PRs
2. **Matrix Builds**: Parallelize tests with sharding
3. **Caching**: Cache dependencies and build artifacts
4. **Reusable Workflows**: Share common workflows across repos
5. **Environments**: Use environments for deployment approvals
6. **Secrets**: Never hardcode secrets; use GitHub Secrets

Google Antigravity's Gemini 3 can generate GitHub Actions workflows from deployment requirements and suggest optimizations.