GitHub Actions

Automate software workflows directly in your GitHub repository with GitHub Actions.

When to Use This Skill

Use this skill when:

• Setting up CI/CD pipelines for GitHub repositories
• Automating build, test, and deployment workflows
• Creating reusable workflow components
• Configuring self-hosted runners
• Managing workflow secrets and variables
• Debugging failed workflow runs

Scope and Fragment Prerequisites

Examples are independent YAML fragments, not a complete deployable pipeline. Each new job needs its own checkout, tool setup, locked dependency installation and artifact transfer; jobs do not share a working directory. Review untrusted event inputs, least-privilege permissions, protected environments and secret exposure before adoption. Image push, deployment and runner registration require authorization.

Prerequisites

• GitHub repository with write access
• Understanding of YAML syntax
• For self-hosted runners: server with Docker (optional)

Workflow File Structure

Workflows are defined in .github/workflows/ directory:

name: CI Pipeline

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

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Setup Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '22'
          cache: 'npm'
      - run: npm ci
      - run: npm test

Common Triggers

Push and Pull Request

on:
  push:
    branches: [main]
    paths:
      - 'src/**'
      - 'package.json'
  pull_request:
    branches: [main]

Scheduled Runs

on:
  schedule:
    - cron: '0 2 * * *'  # Daily at 2 AM UTC

Manual Dispatch

on:
  workflow_dispatch:
    inputs:
      environment:
        description: 'Deployment environment'
        required: true
        default: 'staging'
        type: choice
        options:
          - staging
          - production

Job Configuration

Matrix Builds

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [22, 24]
        os: [ubuntu-latest, windows-latest]
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}
      - run: npm test

Job Dependencies

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - run: npm run build
      
  test:
    needs: build
    runs-on: ubuntu-latest
    steps:
      - run: npm test
      
  deploy:
    needs: [build, test]
    runs-on: ubuntu-latest
    steps:
      - run: ./deploy.sh

Environment Protection

jobs:
  deploy:
    runs-on: ubuntu-latest
    environment:
      name: production
      url: https://example.com
    steps:
      - run: ./deploy.sh

Secrets and Variables

Using Secrets

steps:
  - name: Deploy
    env:
      AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
      AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
    run: aws s3 sync ./dist s3://my-bucket

Using Variables

steps:
  - name: Build
    env:
      API_URL: ${{ vars.API_URL }}
    run: npm run build

Caching Dependencies

- uses: actions/cache@v4
  with:
    path: ~/.npm
    key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
    restore-keys: |
      ${{ runner.os }}-node-

Artifacts

Upload Artifacts

- uses: actions/upload-artifact@v4
  with:
    name: build-output
    path: dist/
    retention-days: 5

Download Artifacts

- uses: actions/download-artifact@v4
  with:
    name: build-output
    path: dist/

Docker Builds

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      
      - name: Login to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}
      
      - name: Build and push
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: user/app:latest

Reusable Workflows

Define Reusable Workflow

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

on:
  workflow_call:
    inputs:
      environment:
        required: true
        type: string
    secrets:
      deploy_key:
        required: true

jobs:
  deploy:

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