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Cheatsheet#github-actions-cheatsheet

GitHub Actions Cheatsheet

GitHub Actions makes it easy to automate all your software workflows, including CI/CD. Workflows are defined using YAML files stored in the .github/workflows/ directory of your repository.

Basic Workflow Structure (.github/workflows/main.yml)

name: CI/CD Pipeline
 
# When does the workflow run?
on:
  push:
    branches: [ "main" ]
  pull_request:
    branches: [ "main" ]
  workflow_dispatch:  # Allows manual triggering from the GitHub UI
 
# What does the workflow do?
jobs:
  build:
    runs-on: ubuntu-latest # The runner environment
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v3
 
      - name: Set up Node.js
        uses: actions/setup-node@v3
        with:
          node-version: '18'
 
      - name: Install dependencies
        run: npm ci
 
      - name: Run tests
        run: npm test

Common Triggers (on)

on:
  push:
    tags:
      - 'v*.*.*'       # Trigger on version tags (e.g., v1.0.0)
  schedule:
    - cron: '0 0 * * *' # Run daily at midnight UTC
  repository_dispatch:
    types: [custom_event] # Trigger via API

Environment Variables and Secrets

jobs:
  deploy:
    runs-on: ubuntu-latest
    env:
      NODE_ENV: production # Available to all steps in this job
    steps:
      - name: Deploy to Server
        run: ./deploy.sh
        env:
          API_KEY: ${{ secrets.PROD_API_KEY }} # Accessing a GitHub Secret

Matrix Builds

Run a job multiple times with different variable combinations (e.g., testing against multiple Node versions).

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [14, 16, 18]
    steps:
      - uses: actions/checkout@v3
      - name: Use Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v3
        with:
          node-version: ${{ matrix.node-version }}
      - run: npm test