Project Overview

This project is a Tier-2 web application that allows users to generate and download QR codes for text, URLs, or custom input. It consists of a lightweight frontend website, a Python-based backend API for QR generation, and a fully automated CI/CD pipeline that builds, containerizes, and deploys the application to AWS.

The system is designed to be cost-optimized, modular, and easy to extend. Each component is Dockerized, and deployments are handled through Amazon ECS, with images stored in Amazon ECR. The CI/CD pipeline is implemented using Jenkins and intelligently rebuilds and deploys only the components that have changed.

Features:

• Generate QR codes for text, URLs, or custom input

• Download generated QR codes as images

• Simple and responsive frontend website

• Backend API for QR generation

• Dockerized application components

• Automated CI/CD pipeline using Jenkins

• Optimized AWS infrastructure using ECS + ECR

Tech Stack:

• Backend: Python

• Frontend: HTML, JavaScript

• CI/CD: Jenkins

• Containerization: Docker, Amazon ECR

• Deployment: Amazon ECS

  CI/CD Pipeline Flow
  
  Developer Commit
          ↓
  GitHub Webhook
          ↓
  Jenkins
          ↓
  Detect Changed Component(s)
          ↓
  Build & Test Only Changed Folder(s)
          ↓
  Docker Image Build
          ↓
  Push Image to Amazon ECR
          ↓
  Deploy Updated Image to Amazon ECS
          ↓
  Live Website
  

Execution Steps:

• Clone the Repository

  git clone https://github.com/Harshit10j2004/CICD-pipeline_for_containerized_app.git
  cd CICD-pipeline_for_containerized_app
  

• Backend Setup (Local)

  cd backend
  pip install -r requirements.txt
  python app.py
  

• Docker Build

    docker build -t backend .
  

• Frontend setup (Local)

  cd frontend
  

• Docker Build

  docker build -t frontend .
  

• Docker compose for testing locally

  cd ..
  docker compose up
  

After testing all things

• Jenkins setup

  Verify Jenkins Is Running

  sudo systemctl status jenkins
  

  If not running:

  sudo systemctl start jenkins
  sudo systemctl enable jenkins
  

  Open in browser:

  http://<EC2-PUBLIC-IP>:8080
  

  Install Required Jenkins Plugins

  Go to:

  Manage Jenkins → Plugins → Available
  

  Install:

  • Git

  • GitHub

  • Pipeline

  • Docker Pipeline

  • AWS

  Restart Jenkins if prompted.

  Install Docker on EC2 (Required for Builds)

  Jenkins runs on host, but Docker must exist.

  sudo apt update
  sudo apt install -y docker.io
  sudo systemctl start docker
  sudo systemctl enable docker
  

  Add Credentials in Jenkins

  • GitHub Credentials

    Manage Jenkins → Credentials → System → Global → Add Credentials

    Kind: Username with password
    
    Username: GitHub username
    
    Password: GitHub personal access token
    
    ID: github-creds
    

  • AWS Credentials

    Manage Jenkins → Credentials → System → Global → Add Credentials

    Kind: AWS Credentials
    
    Access Key ID
    
    Secret Access Key
    
    ID: aws-creds
    

  • Create Pipeline Job

    Jenkins Dashboard → New Item

    Name: qr-app-pipeline

    Type: Pipeline

    Click OK

  • Configure Pipeline Job General:

    GitHub project

    https://github.com/<username>/<repo>
    

    Build Triggers

    GitHub hook trigger for GITScm polling
    
     Do NOT enable polling
    

    Pipeline

    Definition: Pipeline script from SCM

    SCM: Git

    Repository URL:

    https://github.com/<username>/<repo>.git
    

    Credentials: github-creds

      Branch:
      
      */main
    

    Script Path:

    Jenkinsfile
    

    Save.

  • Configure GitHub Webhook

    GitHub repo → Settings → Webhooks → Add Webhook

    Payload URL:

    http://<EC2-PUBLIC-IP>:8080/github-webhook/
    

    Content type: application/json

    Secret: empty

    Events: Just push

    Active:

    Save.

• Verify Webhook Delivery

  GitHub → Webhooks → Click webhook → Recent Deliveries

  You must see:

  200 OK

  If not:

  Port 8080 blocked in EC2 Security Group

  Jenkins not running

  Wrong URL

• End-to-End Test

  git commit -am "webhook test"
  git push origin main
  

Expected:

Jenkins job auto-triggers

Console log prints:

Webhook triggered Jenkins successfully

See my Blog for information and journey:

https://harshithere.hashnode.dev/beyond-manual