GitHub Actions Workflow

🔥 Vibe Prompt

"Create a GitHub Actions workflow: Node.js 20, triggered on push to main, npm ci, lint, test, build."

name: CI Pipeline
on:
  push:
    branches: [main, develop]
  pull_request:
    branches: [main]
jobs:
  build:
    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 run lint
      - run: npm test
      - run: npm run build

Anatomy of a Workflow

| Component | Description | |-----------|-------------| | on | Trigger event | | jobs | Groups of steps | | runs-on | Runner type | | steps | Individual actions | | uses | Reusable action | | run | Shell command |

Chapter Summary

Understand core concepts and principles
Master implementation methods and techniques
Familiar with common issues and solutions
Able to apply in real projects

Implementation Example

Basic Example

# This section provides a complete implementation example

Steps

Setup: Configure development environment
Data: Prepare required data
Implementation: Build core functionality
Testing: Verify correctness
Optimization: Improve performance

Common Errors

| Error Type | Cause | Solution | |------------|-------|----------| | Compilation | Syntax | Check code syntax | | Runtime | Environment | Verify dependencies installed | | Logic | Algorithm | Step-by-step debugging | | Performance | Efficiency | Use profilers |

Code Example

import sys

def main():
    print("Hello, World!")

if __name__ == "__main__":
    main()

References

Official documentation
API reference
Open source examples
Community discussions

GitHub Actions Workflow Structure

A workflow is an automated process defined in YAML. Each workflow lives in .github/workflows/.

name: CI Pipeline  # Workflow name (displayed in GitHub UI)

on:               # Trigger events
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:             # Tasks to execute
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm ci
      - run: npm test

Workflow Components

| Component | Description | |-----------|-------------| | name | Display name for the workflow | | on | Event that triggers the workflow | | jobs | Collection of jobs to execute | | runs-on | Runner OS (ubuntu, windows, macos) | | steps | Individual tasks within a job | | uses | Reuse an action from the marketplace | | run | Execute a shell command | | with | Pass inputs to an action | | env | Set environment variables | | needs | Dependencies between jobs |

Trigger Events

| Event | When It Fires | |-------|-------------| | push | Code pushed to a branch | | pull_request | PR opened, synchronized, reopened | | schedule | Cron-based schedule | | workflow_dispatch | Manual trigger (UI button) | | release | Release published | | issues | Issue opened, closed | | deployment | Deployment created | | registry_package | Package published |

Marketplace Actions

| Action | Purpose | Creator | |--------|---------|---------| | actions/checkout | Check out repository | GitHub | | actions/setup-node | Install Node.js | GitHub | | actions/setup-python | Install Python | GitHub | | docker/login-action | Login to container registry | Docker | | docker/build-push-action | Build and push Docker image | Docker | | amondnet/vercel-action | Deploy to Vercel | Community | | aws-actions/configure-aws-credentials | AWS access | AWS | | azure/webapps-deploy | Deploy to Azure | Microsoft | | google-github-actions/auth | GCP auth | Google | | codecov/codecov-action | Upload coverage reports | Codecov |

Environment Variables

jobs:
  deploy:
    runs-on: ubuntu-latest
    env:
      NODE_ENV: production
      API_URL: https://api.example.com
    steps:
      - uses: actions/checkout@v4
      - run: npm ci
      - run: npm run build
        env:
          NEXT_PUBLIC_API_URL: https://api.example.com
      - run: npm test
        env:
          DATABASE_URL: ${{ secrets.DATABASE_URL }}

Secrets

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Deploy to production
        run: |
          curl -X POST https://api.example.com/deploy \
            -H "Authorization: Bearer ${{ secrets.DEPLOY_TOKEN }}"

Job Dependencies

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm ci && npm run lint

  test:
    needs: [lint]  # Runs AFTER lint succeeds
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm ci && npm test

  build:
    needs: [test]  # Runs AFTER test succeeds
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm ci && npm run build

Matrix Builds

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

Caching Dependencies

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: '20'
          cache: 'npm'  # Automatically caches ~/.npm
      - run: npm ci
      - run: npm test

Summary

GitHub Actions automates CI/CD workflows directly in your repository. Define workflows in YAML, trigger on push/PR/schedule, use marketplace actions, manage secrets, and cache dependencies for speed.

Key takeaways:

Workflows are YAML files in .github/workflows/
Trigger on push, PR, schedule, or manually
Jobs run in parallel by default; use needs for dependencies
Use matrix to test multiple versions/configs
Cache dependencies with cache: npm or actions/cache
Secrets stored in GitHub, referenced as ${{ secrets.NAME }}
Marketplace: 20,000+ reusable actions
Environment variables at workflow, job, and step levels

What's Next: Docker Push

The next chapter covers building and pushing Docker images in CI/CD pipelines.