github-actions

GitHub Actions CI/CD

Summary

GitHub Actions is GitHub's native CI/CD platform for automating software workflows. Define workflows in YAML files to build, test, and deploy code directly from your repository with event-driven automation.

When to Use

• Automate testing on every pull request
• Build and deploy applications on merge to main
• Schedule regular tasks (nightly builds, backups)
• Publish packages to registries (npm, PyPI, Docker Hub)
• Run security scans and code quality checks
• Automate release processes and changelog generation

Quick Start

Basic Test Workflow

Create .github/workflows/test.yml:

name: Test

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'
      - run: npm ci
      - run: npm test

Complete GitHub Actions Guide

Core Concepts

Workflows

YAML files in .github/workflows/ that define automation pipelines.

Structure:

• Name: Workflow identifier
• Triggers: Events that start the workflow
• Jobs: One or more jobs to execute
• Steps: Commands/actions within each job

name: CI Pipeline
on: [push, pull_request]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: echo "Building project"

Jobs

Independent execution units that run in parallel by default.

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - run: npm run lint

  test:
    runs-on: ubuntu-latest
    needs: lint  # Wait for lint to complete
    steps:
      - run: npm test

  deploy:
    runs-on: ubuntu-latest
    needs: [lint, test]  # Wait for both
    steps:
      - run: ./deploy.sh

Steps

Sequential commands or actions within a job.

steps:
  # Use pre-built action
  - uses: actions/checkout@v4

  # Run shell command
  - run: npm install

  # Named step with environment
  - name: Run tests
    run: npm test
    env:
      NODE_ENV: test