In this case study, we will explore the implementation of CI/CD practices in a web project. This will include setting up a CI/CD pipeline, automating builds and tests, deploying to a staging environment, and finally deploying to production. By the end of this case study, you should have a clear understanding of how to apply CI/CD principles to a real-world web project.

We will use a simple web application built with the following stack:

• Frontend: React.js
• Backend: Node.js with Express
• Database: MongoDB

1. Automate the build process for both frontend and backend.
2. Run automated tests to ensure code quality.
3. Deploy the application to a staging environment for testing.
4. Deploy the application to a production environment.

• Version Control: Git and GitHub
• CI Tool: Jenkins
• Deployment Platform: AWS (Amazon Web Services)

1. Install Jenkins:

   • Follow the official Jenkins installation guide for your operating system: Jenkins Installation Guide

2. Configure Jenkins:

   • Install necessary plugins:
     • Git Plugin
     • NodeJS Plugin
     • Docker Plugin (if using Docker for deployment)
   • Create a new Jenkins job for the web project.

1. Source Code Management:

   • Configure the job to pull the code from the GitHub repository.

   git url: 'https://github.com/your-repo/web-project.git'
   

2. Build Triggers:

   • Set up the job to trigger on every push to the repository.

   triggers {
       scm('H/5 * * * *')
   }
   

3. Build Steps:

   • Install Node.js and dependencies.

   npm install
   

   • Build the frontend and backend.

   npm run build
   

4. Post-build Actions:

   • Archive the build artifacts.

   archiveArtifacts 'build/**'
   

1. Unit Tests:

   • Write unit tests for both frontend and backend using Jest.
   • Example test for a React component:

     import React from 'react';
     import { render } from '@testing-library/react';
     import App from './App';
     
     test('renders learn react link', () => {
       const { getByText } = render(<App />);
       const linkElement = getByText(/learn react/i);
       expect(linkElement).toBeInTheDocument();
     });
     

2. Integration Tests:

   • Write integration tests for API endpoints using Supertest.
   • Example test for an Express endpoint:

     const request = require('supertest');
     const app = require('../app');
     
     describe('GET /api/users', () => {
       it('should return a list of users', async () => {
         const res = await request(app).get('/api/users');
         expect(res.statusCode).toEqual(200);
         expect(res.body).toHaveProperty('users');
       });
     });
     

1. Add Test Steps:

   • Run unit and integration tests as part of the build process.

   npm test
   

2. Publish Test Results:

   • Use Jenkins plugins to publish test results.

   junit 'test-results.xml'
   

1. Create a Staging Environment:

   • Use AWS EC2 instances or Docker containers to set up a staging environment.

2. Deploy to Staging:

   • Use Jenkins to automate the deployment process.

   sshPublisher(publishers: [
       sshPublisherDesc(configName: 'staging-server', transfers: [
           sshTransfer(sourceFiles: 'build/**', remoteDirectory: '/var/www/html', removePrefix: 'build')
       ])
   ])
   

1. Run Smoke Tests:
   • Ensure the application is running correctly in the staging environment.
   • Example smoke test:

     curl -f http://staging-server/api/health || exit 1
     

1. Create a Production Environment:

   • Use AWS EC2 instances or Docker containers to set up a production environment.

2. Deploy to Production:

   • Use Jenkins to automate the deployment process.

   sshPublisher(publishers: [
       sshPublisherDesc(configName: 'production-server', transfers: [
           sshTransfer(sourceFiles: 'build/**', remoteDirectory: '/var/www/html', removePrefix: 'build')
       ])
   ])
   

1. Set Up Monitoring:

   • Use tools like AWS CloudWatch or New Relic to monitor the application.
   • Configure alerts for critical metrics.

2. Collect Feedback:

   • Gather feedback from users and stakeholders to continuously improve the application.

In this case study, we covered the end-to-end implementation of CI/CD for a web project. We set up a CI environment using Jenkins, automated the build and test processes, deployed to staging and production environments, and set up monitoring and feedback mechanisms. By following these steps, you can ensure a smooth and efficient CI/CD pipeline for your web projects.

• Apply these principles to your own web projects.
• Explore more advanced CI/CD practices and tools.
• Continue learning and improving your CI/CD pipeline.