Microservice with FastAPI

A small example microservices project using FastAPI, Redis OM and a simple React frontend.

This repository contains two FastAPI microservices and a React frontend used to manage a simple inventory and payments flow:

• inventory — product storage and management (uses Redis OM)
• payment — creates orders and publishes events for inventory updates
• inventory-frontend — React app that interacts with the services

Architecture overview

• The payment service calls the inventory service to fetch product details before creating an order.
• When an order completes the payment service publishes an order_completed stream entry to Redis.
• The inventory consumer (inventory/consumer.py) listens to order_completed and decrements product quantities.
• If something goes wrong the inventory consumer writes to a refund_order stream which the payment consumer listens to and marks orders as refunded.

Services and endpoints

• Inventory service (default port: 8000)

  • GET /products — list product IDs
  • POST /products — create a product (expects a Product model)
  • GET /products/{pk} — get product details
  • DELETE /products/{pk} — delete a product

• Payment service (default port: 8001)

  • POST /orders — create an order (contacts inventory service)
  • GET /orders/{pk} — get order status

Running locally

Prerequisites:

• Python 3.8+ (venv recommended)
• Node.js + npm (for the frontend)
• A Redis instance accessible to the services. The example code currently uses a hosted Redis instance with credentials in main.py; for production or local testing update the connection settings appropriately.

Backend (Python services)

1. Create a virtual environment and install dependencies for each service. From repository root:

python -m venv .venv
.venv\Scripts\activate      # Windows
pip install -r inventory/requirements.txt
pip install -r payment/requirements.txt

2. Start the services in separate terminals:

# Inventory service
uvicorn inventory.main:app --reload --port 8000

# Payment service
uvicorn payment.main:app --reload --port 8001

3. Start the background consumers (separate terminals):

python inventory/consumer.py
python payment/consumer.py

Notes about Redis

• The code currently creates a redis connection inline in inventory/main.py and payment/main.py. For safer local development, either run a local Redis server and update the connection parameters, or refactor to use environment variables (recommended).

Frontend

1. Install and start the React frontend:

cd inventory-frontend
npm install
npm start

The frontend is configured to call http://localhost:8000 and http://localhost:8001 by default; ensure the backend services are running on those ports or update the frontend accordingly.

Development tips

• Port mapping: inventory -> 8000, payment -> 8001, frontend -> 3000
• Run consumers to process Redis streams and keep state consistent.
• Consider moving the Redis connection settings to environment variables or a config file before sharing or deploying this repo.

Files of interest

• inventory/main.py — inventory API and Product model
• inventory/consumer.py — listens for order_completed stream
• payment/main.py — order creation and publishing
• payment/consumer.py — listens for refund_order stream
• inventory-frontend — React frontend

License

This example is provided as-is for learning purposes.