🔥 DevOps Demo Application - Backend¶

The backend of our DevOps demo application is built with FastAPI, providing a high-performance, easy-to-use API with automatic interactive documentation.

💻 Table of Contents¶

Features
Requirements
Development Setup
Docker-based Development
Local Development
API Documentation
Project Structure
Database
Testing
Deployment

✨ Features¶

FastAPI Framework: High-performance, easy to learn, fast to code, ready for production
SQLModel ORM: SQL databases in Python, designed for simplicity, compatibility, and robustness
JWT Authentication: Secure authentication with JWT tokens
Automatic API Documentation: Interactive API documentation with Swagger UI and ReDoc
Dependency Injection: Clean and testable code with FastAPI's dependency injection system
Async Support: Fully asynchronous API endpoints for high performance
Comprehensive Testing: Pytest-based test suite with high coverage

📍 Requirements¶

Docker and Docker Compose
Python 3.11+
uv for Python package and environment management
PostgreSQL (when running locally without Docker)

🔧 Development Setup¶

Docker-based Development¶

The easiest way to get started is using Docker Compose, which sets up all required services including the database.

# From the project root directory
docker compose up -d

This will start:

Backend API at http://api.localhost
PostgreSQL database
Adminer (database management) at http://adminer.localhost

Local Development¶

For a more responsive development experience, you can run the backend locally.

Set up environment variables

# From the project root directory
cp .env.example .env
# Edit .env with your preferred settings

Install dependencies

# Navigate to backend directory
cd backend

# Create a virtual environment
uv venv

# Activate the virtual environment
source .venv/bin/activate  # On Windows: .venv\Scripts\activate

# Install dependencies
uv pip install -e .

Start the development server

uvicorn app.main:app --reload --host 0.0.0.0 --port 8000

📖 API Documentation¶

FastAPI automatically generates interactive API documentation:

Swagger UI: http://localhost:8000/docs
Interactive documentation with request/response examples
Try out API endpoints directly from the browser
ReDoc: http://localhost:8000/redoc
Alternative documentation interface
More readable for complex APIs

📂 Project Structure¶

backend/
├── app/
│   ├── api/
│   │   ├── deps.py         # Dependency injection
│   │   └── routes/         # API endpoints
│   ├── core/               # Core functionality
│   │   ├── config.py       # Configuration
│   │   └── security.py     # Security utilities
│   ├── crud/               # CRUD operations
│   ├── db/                 # Database setup
│   ├── models/             # SQLModel models
│   ├── schemas/            # Pydantic schemas
│   ├── tests/              # Tests
│   └── main.py             # Application entry point
└── pyproject.toml          # Project dependencies

💾 Database¶

Migrations¶

The application uses Alembic for database migrations:

# Generate a new migration
alembic revision --autogenerate -m "description"

# Apply migrations
alembic upgrade head

Database Models¶

Models are defined using SQLModel, which combines SQLAlchemy and Pydantic:

from sqlmodel import Field, SQLModel

class User(SQLModel, table=True):
    id: int = Field(default=None, primary_key=True)
    email: str = Field(unique=True, index=True)
    # ...

🧪 Testing¶

The backend includes a comprehensive test suite using pytest:

# Run all tests
pytest

# Run tests with coverage report
pytest --cov=app

# Run specific test file
pytest app/tests/api/routes/test_users.py

🚀 Deployment¶

The backend is designed to be deployed as a Docker container to AWS ECS. The deployment is handled automatically by GitHub Actions when changes are pushed to the appropriate branches.

For more information on the deployment process, see the CI/CD Pipeline section in the main README.