How CI/CD Works - Understanding Continuous Integration and Delivery

What is CI/CD

CI/CD (Continuous Integration / Continuous Delivery/Deployment) is an automation practice in software development.

• CI (Continuous Integration): Frequently integrates code changes into the main branch with automated builds and tests
• CD (Continuous Delivery): In addition to CI, automates deployment preparation to production
• CD (Continuous Deployment): Automatically deploys to production when tests pass

Why is CI/CD important: Manual builds, tests, and deployments are time-consuming and prone to human error.

CI/CD Pipeline Flow

flowchart LR
    Source --> Build --> Test --> Deploy --> Monitor

1. Source: Commit, push, create PR
2. Build: Install dependencies, compile
3. Test: Unit, integration, E2E tests
4. Deploy: Deploy to staging and production environments
5. Monitor: Health checks, error monitoring

GitHub Actions Example

name: CI Pipeline
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  build-and-test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: '20'
      - run: npm ci
      - run: npm run lint
      - run: npm test
      - run: npm run build

Deployment Strategies

Summary

CI/CD is an essential practice in modern software development. Through automation, you can reduce human errors and get rapid feedback.