SimpleWebAppPython - Notes App

A full-featured Flask notes application for testing docker-compose to Kubernetes deployment via K3s AI Manager.

Features

• ✅ Full CRUD operations (Create, Read, Update, Delete)
• ✅ SQLite database with persistent storage
• ✅ RESTful API endpoints
• ✅ Beautiful, responsive UI
• ✅ Health check endpoint
• ✅ Ready for docker-compose deployment
• ✅ Kubernetes-ready with persistent volumes
• ✅ Load balanced with 2 replicas

Quick Start (Local Testing)

Using Docker Compose

docker-compose up --build

Visit: http://localhost:8080

Using Python Directly

pip install -r requirements.txt
python app.py

Visit: http://localhost:8080

Deploy to Kubernetes via K3s AI Manager

Step 1: Access Your Ubuntu Deployment

1. Open K3s AI Manager
2. Navigate to Deployments
3. Click Configure on your Ubuntu deployment
4. Access the terminal

Step 2: Clone This Repository

cd ~
git clone https://github.com/mozeal/SimpleWebAppPython.git
cd SimpleWebAppPython

Step 3: Deploy via docker-compose

1. In the Ubuntu Configure modal, click "Deploy docker-compose"
2. Fill in the form:
   • Compose File Path: /home/ubuntu/SimpleWebAppPython/docker-compose.yml
   • Deployment Name: notes-app (or your choice)
   • Custom Subdomain (optional): my-notes
3. Click Preview to see what will be deployed
4. Click Deploy and watch the build progress
5. Once complete, click the generated URL to see your app!

Step 4: Access Your Deployed App

Your app will be available at:

https://web-notes-app.artech.cloud

Or with custom subdomain:

https://web-my-notes.artech.cloud

Endpoints

Endpoint	Method	Description
/	GET	Home page with notes interface
/health	GET	Health check endpoint (JSON)
/api/info	GET	System information (JSON)
/api/notes	GET	Get all notes (JSON)
/api/notes	POST	Create new note (JSON)
/api/notes/<id>	GET	Get specific note (JSON)
/api/notes/<id>	PUT	Update note (JSON)
/api/notes/<id>	DELETE	Delete note

API Examples

Create a Note

curl -X POST https://web-notes-app.artech.cloud/api/notes \
  -H "Content-Type: application/json" \
  -d '{"title":"My First Note","content":"Hello from the API!"}'

Get All Notes

curl https://web-notes-app.artech.cloud/api/notes

Update a Note

curl -X PUT https://web-notes-app.artech.cloud/api/notes/1 \
  -H "Content-Type: application/json" \
  -d '{"title":"Updated Title","content":"Updated content"}'

Delete a Note

curl -X DELETE https://web-notes-app.artech.cloud/api/notes/1

File Structure

SimpleWebAppPython/
├── app.py                  # Flask application with SQLite
├── templates/
│   └── index.html         # Interactive notes UI
├── requirements.txt        # Python dependencies
├── Dockerfile             # Container image definition
├── docker-compose.yml     # Deployment configuration
└── README.md              # This file

What Gets Deployed?

When you deploy this app using docker-compose:

• 2 replicas of the web service (load balanced)
• 512MB RAM limit per pod
• 0.5 CPU limit per pod
• Persistent volume for SQLite database
• Automatic health checks every 30 seconds
• HTTPS URL with automatic routing via Traefik
• Zero-downtime rolling updates

Database Persistence

Notes are stored in a SQLite database located at /data/notes.db inside the container. This directory is mounted as a Kubernetes PersistentVolume, ensuring your notes persist across:

• Pod restarts
• Deployments updates
• Container crashes

Technology Stack

• Backend: Flask (Python)
• Database: SQLite
• Frontend: Vanilla JavaScript with modern CSS
• Container: Python 3.11 slim
• Orchestration: Kubernetes (via K3s)
• Ingress: Traefik

Customization

Change Port

Edit docker-compose.yml:

ports:
  - "3000:3000"  # External:Internal
environment:
  PORT: 3000

Change Replicas

Edit docker-compose.yml:

deploy:
  replicas: 3  # Increase for higher availability

Adjust Resource Limits

Edit docker-compose.yml:

deploy:
  resources:
    limits:
      cpus: '1.0'
      memory: 1024M

Troubleshooting

Build Fails

Problem: Image build fails with "file not found" Solution: Ensure all files exist in the repository:

ls -la ~/SimpleWebAppPython/
# Should show: app.py, Dockerfile, docker-compose.yml, requirements.txt, templates/

App Won't Start

Problem: Pods crash or won't start Solution: Check logs in K3s AI Manager:

1. Click deployment status
2. View logs
3. Look for errors in application startup

Database Not Persisting

Problem: Notes disappear after restart Solution: Ensure persistent volume is correctly mounted:

kubectl get pvc -n <namespace>
# Should show a PVC bound to the volume

Can't Access URL

Problem: URL returns 404 or connection error Solution:

1. Wait 30 seconds after deployment completes (DNS propagation)
2. Check pod status - should show "2/2 Running"
3. Verify HTTPS (not HTTP) in URL

Architecture

This app demonstrates a production-ready deployment pattern:

┌─────────────────────────────────────────┐
│  User Browser                           │
└──────────────┬──────────────────────────┘
               │ HTTPS
               ▼
┌─────────────────────────────────────────┐
│  Traefik Ingress Controller             │
│  (Automatic HTTPS, Load Balancing)      │
└──────────────┬──────────────────────────┘
               │
        ┌──────┴──────┐
        │             │
        ▼             ▼
┌──────────┐    ┌──────────┐
│  Pod 1   │    │  Pod 2   │
│  Flask   │    │  Flask   │
│  SQLite  │    │  SQLite  │
└────┬─────┘    └────┬─────┘
     │               │
     └───────┬───────┘
             ▼
┌─────────────────────────────────────────┐
│  Persistent Volume (notes-data)         │
│  SQLite Database                        │
└─────────────────────────────────────────┘

Development

Run locally with auto-reload:

export FLASK_ENV=development
python app.py

Run tests:

# Install test dependencies
pip install pytest requests

# Run tests (example)
pytest tests/

License

MIT License - Feel free to use this for learning and testing!

Support

For issues with the app, open an issue on GitHub.

For issues with K3s AI Manager deployment, check the main documentation.

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Happy Deploying! 🚀