🐳 Docker Flask Application

A simple, production-ready Flask web application containerized with Docker, demonstrating DevOps best practices.

📋 Features

• ✅ Lightweight Python Flask web application
• ✅ Multi-stage Docker build for optimized image size
• ✅ Docker Compose for easy orchestration
• ✅ Non-root user for enhanced security
• ✅ Health check endpoint
• ✅ RESTful API endpoints
• ✅ Production-ready with Gunicorn
• ✅ Makefile for common commands

🏗️ Project Structure

docker-flask-app/
├── app/
│   └── app.py              # Main Flask application
├── tests/                   # Test directory (for future tests)
├── .dockerignore           # Docker ignore file
├── .gitignore              # Git ignore file
├── docker-compose.yml      # Docker Compose configuration
├── Dockerfile              # Multi-stage Dockerfile
├── Makefile                # Common commands
├── README.md               # This file
└── requirements.txt        # Python dependencies

🚀 Quick Start

Prerequisites

• Docker installed (Install Docker)
• Docker Compose installed (Install Docker Compose)
• Git (optional, for version control)

Running the Application

1. Clone or download this project

2. Build and run with Docker Compose:

   docker-compose up -d

3. Or use the Makefile:

   make run-build

4. Access the application:

   • Homepage: http://localhost:5000
   • Health Check: http://localhost:5000/api/health
   • Info: http://localhost:5000/api/info

🛠️ Available Commands

Using Makefile (Recommended)

make help          # Show all available commands
make build         # Build the Docker image
make run           # Run the container
make run-build     # Build and run
make stop          # Stop the container
make restart       # Restart the container
make logs          # View logs
make shell         # Open shell in container
make clean         # Remove container and image
make test          # Test the health endpoint

Using Docker Compose

docker-compose up -d              # Start in detached mode
docker-compose down               # Stop and remove containers
docker-compose logs -f            # Follow logs
docker-compose ps                 # List containers
docker-compose restart            # Restart services

Using Docker Directly

# Build image
docker build -t docker-flask-app .

# Run container
docker run -d -p 5000:5000 --name flask-app docker-flask-app

# View logs
docker logs -f flask-app

# Stop container
docker stop flask-app

# Remove container
docker rm flask-app

📡 API Endpoints

Method	Endpoint	Description
GET	/	Homepage with info
GET	/api/health	Health check endpoint
GET	/api/info	System information

🔧 Configuration

Environment variables can be set in docker-compose.yml:

environment:
  - ENVIRONMENT=development  # or production
  - PORT=5000

🧪 Testing

Test the health endpoint:

curl http://localhost:5000/api/health

Expected response:

{
  "status": "healthy",
  "service": "docker-flask-app"
}

📦 Docker Best Practices Implemented

1. Multi-stage builds - Smaller final image size
2. Non-root user - Enhanced security
3. Layer caching - Faster builds
4. .dockerignore - Exclude unnecessary files
5. Health checks - Container health monitoring
6. Explicit base image versions - Reproducible builds
7. Minimal base image - Using slim Python image

🚢 Deployment

Push to Docker Hub

# Tag the image
docker tag docker-flask-app yourusername/docker-flask-app:v1.0

# Login to Docker Hub
docker login

# Push the image
docker push yourusername/docker-flask-app:v1.0

Run from Docker Hub

docker run -d -p 5000:5000 yourusername/docker-flask-app:v1.0

📚 Learning Resources

This project demonstrates:

• Docker containerization
• Multi-stage Docker builds
• Docker Compose orchestration
• Python Flask web framework
• RESTful API design
• DevOps best practices

🔄 Next Steps to Enhance

• Add unit tests with pytest
• Implement CI/CD pipeline (GitHub Actions)
• Add database (PostgreSQL/Redis)
• Kubernetes manifests
• Monitoring with Prometheus
• Logging with ELK stack
• Add Nginx as reverse proxy

📝 License

MIT License - feel free to use this project for learning and portfolio purposes!

👤 Author

Your Name - Your LinkedIn

🤝 Contributing

This is a learning project. Feel free to fork and modify!

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Perfect for: DevOps portfolio, Docker learning, interview preparation, LinkedIn showcase