A robust demonstration of an Event-Driven Microservices Architecture built with Python, FastAPI, RabbitMQ, and Docker.

This project showcases how independent services communicate asynchronously to handle e-commerce workflows like user registration, order placement, and real-time notifications.

The system consists of three independent microservices and a message broker. They communicate through a mix of synchronous REST APIs and asynchronous event publishing.

graph TD
    User((User)) -- HTTP POST/GET --> UserSvc[User Service]
    User -- HTTP POST --> OrderSvc[Order Service]
    
    OrderSvc -- Publish Event --> RMQ[RabbitMQ]
    RMQ -- Consume Message --> NotifSvc[Notification Service]
    
    subgraph "Infrastructure"
        RMQ
    end
    
    subgraph "Internal Storage"
        UserSvc --- UserDB[(SQLite)]
        OrderSvc --- OrderDB[(SQLite)]
    end

• Role: Manages user profiles and identity.
• Tech: FastAPI, Async SQLAlchemy, SQLite.
• Key Feature: Validates email uniqueness and handles user registration.

• Role: Handles the lifecycle of an order.
• Tech: FastAPI, Async SQLAlchemy, RabbitMQ (aio-pika).
• Key Feature: When an order is successfully created, it publishes an order_created event to RabbitMQ.

• Role: Reacts to system events to "notify" users.
• Tech: Python, aio-pika.
• Key Feature: Runs as a background worker. It consumes messages from the order_events queue and logs details to the console.

• Framework: FastAPI (High-performance Python web framework)
• Message Broker: RabbitMQ (Reliable asynchronous messaging)
• ORM: SQLAlchemy 2.0 (Async support)
• Database: SQLite (Local file-based for simplicity)
• Containerization: Docker & Docker Compose
• Async Client: aio-pika (RabbitMQ) & httpx (Testing)

• Docker Desktop
• Python 3.12+ (Only if running tests or development locally)

1. Clone the repository:

   git clone https://github.com/hadithedetonator/ecommerce-microservices.git
   cd ecommerce-microservices

2. Spin up the infrastructure:

   docker-compose up --build

3. Verify running containers:

   docker-compose ps

4. Access RabbitMQ Dashboard:

   • URL: http://localhost:15672
   • Credentials: guest / guest

To verify that the services are working together correctly, follow this sequence:

I have provided an async script that simulates the entire user-to-order flow.

# Setup virtual environment
python3 -m venv tests/venv
source tests/venv/bin/activate
pip install -r tests/requirements.txt

# Run the test
python tests/test_flow.py

You can also test using curl or Postman:

1. Step 1: Create a User

   curl -X POST http://localhost:5001/users \
     -H "Content-Type: application/json" \
     -d '{"name": "John Doe", "email": "john@example.com"}'

2. Step 2: Place an Order

   curl -X POST http://localhost:5002/orders \
     -H "Content-Type: application/json" \
     -d '{"user_id": 1, "product_name": "MacBook Pro", "amount": 2499.99}'

3. Step 3: Check Notifications Watch the docker logs to see the event being consumed:

   docker-compose logs -f notification_service

   Expected Output: [!] NOTIFICATION: Order #1 created for User 1: MacBook Pro ($2499.99)

.
├── docker-compose.yml          # Orchestration
├── user_service/               # User Management API
├── order_service/              # Order Management API (Publisher)
├── notification_service/       # Event Consumer (Worker)
├── tests/                      # Integration test suite
└── readme.md                   # Documentation

Feel free to open issues or submit pull requests to enhance the functionality!