CI/CD Pipeline with Jenkins

This repository contains a complete CI/CD pipeline setup using Jenkins that builds, tests, packages, and deploys a Node.js "Hello World" web application.

Project Structure

ci-1/
├── app/
│   ├── index.js              # Express.js web server
│   ├── package.json          # Node.js dependencies
│   └── test/
│       └── index.test.js     # Jest unit tests
├── Dockerfile                # Multi-stage Docker build
├── docker-compose.yml        # Application deployment
├── docker-compose.jenkins.yml # Jenkins with Docker-in-Docker
├── Jenkinsfile               # Declarative Jenkins pipeline
├── healthcheck.sh            # Health verification script
├── .dockerignore
├── .gitignore
└── README.md

Application

The demo application is a simple Express.js server that:

• Serves "Hello World" on the root endpoint (/)
• Provides a health check endpoint (/health) returning JSON status
• Runs on port 3000

Prerequisites

• Docker and Docker Compose installed
• Jenkins (can be run via Docker Compose - see below)
• Git

Quick Start

Option 1: Run Jenkins in Docker (Docker-in-Docker)

1. Start Jenkins and the application:

   docker-compose -f docker-compose.jenkins.yml up -d

2. Get Jenkins initial admin password:

   docker exec jenkins cat /var/jenkins_home/secrets/initialAdminPassword

3. Access Jenkins at http://localhost:8080 and complete setup

4. Install required Jenkins plugins:

   • Docker Pipeline
   • Docker plugin
   • NodeJS plugin Go to Manage Jenkins > Global Tool Configuration.

   Scroll down to NodeJS and click Add NodeJS.

   Give it a Name (e.g., node-22) and choose a version to install automatically.

Click Save.

5. Create a new Pipeline job in Jenkins:

   • Select "Pipeline script from SCM"
   • Set SCM to Git
   • Repository URL: path to this repository
   • Script Path: Jenkinsfile

6. Run the pipeline

Option 2: Use Existing Jenkins Installation

1. Ensure Docker and Docker Compose are available to Jenkins

2. Create a new Pipeline job:

   • Select "Pipeline script from SCM"
   • Set SCM to Git
   • Repository URL: path to this repository
   • Script Path: Jenkinsfile

3. Run the pipeline

Manual Deployment (Without Jenkins)

1. Build and run the application:

   docker-compose up -d

2. Check health:

   ./healthcheck.sh

3. Access the application:

   • Root: http://localhost:3000
   • Health: http://localhost:3000/health

Pipeline Stages

The Jenkins pipeline includes the following stages:

1. Build: Installs Node.js dependencies
2. Test: Runs Jest unit tests
3. Package: Builds Docker image
4. Deploy: Deploys using Docker Compose
5. Health Check: Verifies container is running and healthy

Health Check

The health check script (healthcheck.sh) verifies:

• Container is running
• /health endpoint responds with status 200
• Health endpoint returns valid JSON

Testing

Run tests locally:

cd app
npm install
npm test

Stopping Services

Stop all services:

docker-compose down
# or for Jenkins setup:
docker-compose -f docker-compose.jenkins.yml down

Notes

• The Jenkins container requires Docker socket access for Docker-in-Docker
• Jenkins data is persisted in a Docker volume
• The application container includes built-in health checks
• All Docker images use Alpine Linux for minimal size