68-fastapi-microservices

68 - Microservices with FastAPI

What It Does

Demonstrates a fundamental Microservices Architecture. Instead of one monolithic FastAPI app containing all features, we split the application into two entirely separate services:

1. Users Service (Port 8001): Manages user data.
2. Orders Service (Port 8002): Manages orders. When an order is requested, it uses httpx to synchronously communicate over the network with the Users service to fetch the user's details and stitch the data together.

Includes a unified frontend to query the Orders service and see the stitched data.

Project Structure

68-fastapi-microservices/
  users_service/
    main.py          # Port 8001 server
  orders_service/
    main.py          # Port 8002 server (calls 8001)
  shared/
    models.py        # Pydantic models shared across services (conceptual)
  index.html         # Unified Frontend hitting Port 8002
  requirements.txt   # Dependencies
  README.md          # This file

Setup and Run

1. Install dependencies

pip install -r requirements.txt

2. Start Service 1 (Users)

In a new terminal:

cd users_service
uvicorn main:app --port 8001

3. Start Service 2 (Orders)

In a new terminal:

cd orders_service
uvicorn main:app --port 8002

4. Open the Frontend

Open index.html directly in your browser.

Example Output

{
  "order": {
    "order_id": 101,
    "user_id": 1,
    "items": [{"product": "Laptop", "price": 999.99}]
  },
  "customer": {
    "id": 1,
    "name": "Alice Inwonderland",
    "email": "alice@example.com"
  }
}

Core Concepts

• Service Separation: Complete isolation of domains.
• Service-to-Service Communication: The Orders service acts as a client to the Users service using Python's async httpx library.
• Data Aggregation: The Orders service stitches together its internal order data with the external user data before returning it to the browser.