GitHub Actions

CI/CD automation integrated with GitHub repositories.

When to Use

• Continuous integration testing
• Automated deployments
• Code quality checks
• Workflow automation

Quick Start

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

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

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
          cache: "npm"
      - run: npm ci
      - run: npm test

Core Concepts

Workflow Structure

name: Deploy

on:
  push:
    branches: [main]
  workflow_dispatch:
    inputs:
      environment:
        description: "Target environment"
        required: true
        default: "staging"
        type: choice
        options: [staging, production]

env:
  NODE_VERSION: 20

jobs:
  build:
    runs-on: ubuntu-latest
    outputs:
      version: ${{ steps.version.outputs.version }}
    steps:
      - uses: actions/checkout@v4

      - name: Get version
        id: version
        run: echo "version=$(node -p "require('./package.json').version")" >> $GITHUB_OUTPUT

      - uses: actions/upload-artifact@v4
        with:
          name: dist
          path: dist/

  deploy:
    needs: build
    runs-on: ubuntu-latest
    environment: ${{ inputs.environment || 'staging' }}
    steps:
      - uses: actions/download-artifact@v4
        with:
          name: dist

Matrix Strategy

jobs:
  test:
    runs-on: ${{ matrix.os }}
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest]
        node: [18, 20, 22]
    steps:
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node }}

Common Patterns

Reusable Workflow

# .github/workflows/reusable-deploy.yml
on:
  workflow_call:
    inputs:
      environment:
        required: true
        type: string
    secrets:
      deploy_token:
        required: true

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment: ${{ inputs.environment }}
    steps:
      - run: echo "Deploying to ${{ inputs.environment }}"
        env:
          TOKEN: ${{ secrets.deploy_token }}

# Calling workflow
jobs:
  deploy:
    uses: ./.github/workflows/reusable-deploy.yml
    with:
      environment: production
    secrets:
      deploy_token: ${{ secrets.DEPLOY_TOKEN }}

Best Practices

Do:

• Pin action versions with SHA
• Use environments for deployments
• Cache dependencies
• Use concurrency controls

Don't:

• Expose secrets in logs
• Use pull_request_target carelessly
• Skip security scanning
• Ignore workflow permissions

Troubleshooting

Issue	Cause	Solution
Permission denied	Missing permissions	Add permissions block
Cache miss	Wrong key	Check cache key pattern
Secret empty	Wrong scope	Check secret availability

References

• GitHub Actions Docs
• Actions Marketplace