# Contact List Application

A simple web-based contact list application deployed on Google Kubernetes Engine (GKE) with automated HTTPS certificate provisioning.

## Description

This application allows users to create, view, update, and delete contacts in a persistent MongoDB database. It features a clean, responsive interface and is deployed as a containerized application on Google Cloud Platform using Kubernetes.

## Technologies Used

- **Frontend**: HTML, CSS, JavaScript
- **Backend**: Node.js with Express
- **Database**: MongoDB
- **Containerization**: Docker
- **Orchestration**: Google Kubernetes Engine (GKE)
- **Load Balancing & HTTPS**: GKE Ingress with Google-managed certificates
- **Domain**: Dynamic domain using nip.io DNS service

## Architecture

The application consists of multiple containers:

1. **Contact App**: Node.js application serving the web interface and API
2. **MongoDB**: NoSQL database for storing contact information
3. **Ingress Controller**: Manages external access to the services
4. **Load Balancer**: Distributes incoming traffic

## Key Features

- Responsive web interface
- RESTful API for contact management
- Persistent data storage using MongoDB with PersistentVolumeClaims
- Automatic HTTPS certificate provisioning
- Automatic application restart on failure
- Scalable architecture

## Deployment Files

The application includes the following configuration files:

- **Dockerfile**: Containerizes the Node.js application
- **k8s/**: Kubernetes configuration directory
  - **app-deployment.yaml**: Deployment for the Node.js application
  - **app-service.yaml**: Service for the Node.js application
  - **contact-app-lb.yaml**: LoadBalancer service for obtaining external IP
  - **ingress.yaml**: Template for Ingress configuration
  - **mongo-deployment.yaml**: Deployment for MongoDB
  - **mongo-service.yaml**: Service for MongoDB
  - **mongo-pvc.yaml**: PersistentVolumeClaim for MongoDB data
  - **namespace.yaml**: Namespace for application resources

## Deployment Scripts

### prepare-app.sh

This script handles the entire deployment process:

1. Builds and pushes the Docker image to Google Container Registry
2. Creates a GKE cluster if one doesn't exist
3. Deploys MongoDB with persistent storage
4. Deploys the Contact App application
5. Creates a LoadBalancer service to obtain an external IP
6. Configures Ingress with a dynamic domain using nip.io
7. Sets up HTTPS with Google-managed certificates

### remove-app.sh

This script removes all resources created by the application:

1. Deletes Ingress and certificates
2. Deletes application deployments and services
3. Deletes MongoDB deployment, service, and PVC
4. Removes the Kubernetes namespace

## Usage Instructions

### Prerequisites

1. Google Cloud Platform account with billing enabled
2. Google Cloud SDK installed and configured
3. kubectl installed
4. Docker installed

### Deployment

1. Clone the repository
2. Navigate to the project directory
3. Make the scripts executable:
   ```bash
   chmod +x prepare-app.sh remove-app.sh