Todo App

A simple and elegant todo application built with Python Flask and SQLite, designed for deployment on Kubernetes using Helm and ArgoCD.

Features

• ✅ Clean and modern web interface
• ✅ SQLite database for data persistence
• ✅ Add, complete, and delete todos
• ✅ Real-time task statistics
• ✅ RESTful API endpoints
• ✅ Health check endpoints for Kubernetes
• ✅ Containerized with Docker
• ✅ Kubernetes-ready with Helm charts
• ✅ GitOps deployment with ArgoCD

Quick Start

Local Development

1. Install dependencies:

   pip install -r requirements.txt

2. Run the application:

   python app.py

3. Access the app: Open your browser and go to http://localhost:5000

Docker

1. Build the image:

   docker build -t todo-app:latest .

2. Run the container:

   docker run -p 5000:5000 -v $(pwd)/data:/app/data todo-app:latest

Kubernetes Deployment

Using Helm

1. Install the Helm chart:

   helm install todo-app ./helm/todo-app

2. Upgrade the deployment:

   helm upgrade todo-app ./helm/todo-app

3. Uninstall:

   helm uninstall todo-app

Using kubectl (Raw Manifests)

1. Apply all manifests:

   kubectl apply -f k8s/

2. Check deployment status:

   kubectl get pods -n todo-app
   kubectl get svc -n todo-app

ArgoCD GitOps Deployment

1. Apply the ArgoCD application:

   kubectl apply -f argocd/application.yaml

2. Apply the ArgoCD project (optional):

   kubectl apply -f argocd/appproject.yaml

3. Access ArgoCD UI and sync the application

Configuration

Helm Values

Key configuration options in helm/todo-app/values.yaml:

• replicaCount: Number of pod replicas (default: 2)
• image.repository: Docker image repository
• image.tag: Docker image tag
• persistence.enabled: Enable SQLite data persistence (default: true)
• persistence.size: Storage size for SQLite database (default: 1Gi)
• ingress.enabled: Enable ingress (default: true)
• ingress.hosts[0].host: Hostname for the application (default: todo-app.local)

Environment Variables

• PORT: Application port (default: 5000)

API Endpoints

• GET / - Main todo application interface
• POST /add - Add a new todo
• GET /toggle/<id> - Toggle todo completion status
• GET /delete/<id> - Delete a todo
• GET /api/todos - Get all todos as JSON
• GET /health - Health check endpoint

Database

The application uses SQLite for data storage with the following schema:

CREATE TABLE todos (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    title TEXT NOT NULL,
    description TEXT,
    completed BOOLEAN NOT NULL DEFAULT 0,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

Architecture

┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│     ArgoCD      │───▶│   Kubernetes    │───▶│   Todo App      │
│   (GitOps)      │    │     Cluster     │    │   (Flask)       │
└─────────────────┘    └─────────────────┘    └─────────────────┘
                              │                         │
                              ▼                         ▼
                       ┌─────────────────┐    ┌─────────────────┐
                       │      Helm       │    │     SQLite      │
                       │    (Charts)     │    │   (Database)    │
                       └─────────────────┘    └─────────────────┘

Development

Project Structure

.
├── app.py                 # Main Flask application
├── requirements.txt       # Python dependencies
├── Dockerfile            # Container image definition
├── .dockerignore         # Docker ignore patterns
├── templates/            # HTML templates
│   ├── base.html         # Base template
│   └── index.html        # Main page template
├── k8s/                  # Raw Kubernetes manifests
│   ├── namespace.yaml
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── ingress.yaml
│   └── pvc.yaml
├── helm/                 # Helm chart
│   └── todo-app/
│       ├── Chart.yaml
│       ├── values.yaml
│       └── templates/
└── argocd/              # ArgoCD manifests
    ├── application.yaml
    └── appproject.yaml

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Test locally and with Docker
5. Submit a pull request

Security

• Application runs as non-root user in container
• Resource limits configured for pods
• Health checks implemented for reliability
• SQLite database stored in persistent volume

Monitoring

The application provides a health check endpoint at /health that returns:

{
  "status": "healthy",
  "timestamp": "2024-01-01T12:00:00.000000"
}

License

This project is licensed under the MIT License.