GitHub Actions. CI/CD

GitHub Actions automates tasks that run when events happen in your repo, like testing on every push or deploying on merge to main.

Key concepts

• Workflow, a YAML file in .github/workflows/
• Trigger (on). What event starts the workflow (push, PR, schedule)
• Job. A set of steps that run on a virtual machine
• Step, a single command or action
• Action. A reusable unit of work (e.g. actions/checkout)

Example: Run tests on every push

# .github/workflows/test.yml
name: Tests

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

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Set up PHP
        uses: shivammathur/setup-php@v2
        with:
          php-version: "8.2"
      - name: Install dependencies
        run: composer install
      - name: Run tests
        run: ./vendor/bin/phpunit

Common use cases

• Run unit tests on every PR
• Deploy to production on merge to main
• Send Slack notifications on build failure
• Publish npm packages on tag