fastapi-loadbalancer 0.1.0

A simple load balancer for FastAPI applications.

🚀 FastAPI Load Balancer

A lightweight load balancer for FastAPI applications that distributes traffic across multiple backend services.
It provides round-robin request distribution, automatic failover, caching, and rate limiting.

🌟 Features

✅ Round-robin Load Balancing - Distributes requests evenly across backends.
✅ Health Checks - Automatically detects and removes unhealthy backends.
✅ Auto-Retry & Failover - If a backend is down, the request is retried on another backend.
✅ Rate Limiting (Optional) - Prevent API abuse.
✅ Caching (Optional) - Improve performance by caching responses.

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📦 Installation

Install via pip:

pip install fastapi-loadbalancer

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🚀 Usage

1️⃣ Run Backend Services

You need at least two backend FastAPI servers running.
Example: backend1.py

from fastapi import FastAPI

app = FastAPI()

@app.get("/data")
def get_data():
    return {"backend": "Backend 1", "message": "Hello from Backend 1"}

Run it with:

uvicorn backend1:app --port 8001 --reload

Create another backend (backend2.py) with:

from fastapi import FastAPI

app = FastAPI()

@app.get("/data")
def get_data():
    return {"backend": "Backend 2", "message": "Hello from Backend 2"}

Run it with:

uvicorn backend2:app --port 8002 --reload

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2️⃣ Create the Load Balancer

Now, create a gateway.py file that will act as the load balancer:

from fastapi import FastAPI, Request
from fastapi_loadbalancer import LoadBalancer

app = FastAPI()

# List of backend servers
backend_servers = [
    "http://127.0.0.1:8001",
    "http://127.0.0.1:8002"
]

# Initialize Load Balancer
load_balancer = LoadBalancer(backend_servers)

@app.api_route("/{path:path}", methods=["GET", "POST", "PUT", "DELETE"])
async def handle_request(request: Request, path: str):
    return await load_balancer.proxy_request(request)

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3️⃣ Run the Load Balancer

Now, start the load balancer:

uvicorn gateway:app --port 8000 --reload

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4️⃣ Test the Load Balancer

Send a request to the load balancer:

curl http://127.0.0.1:8000/data

The response will alternate between:

{"backend": "Backend 1", "message": "Hello from Backend 1"}

or

{"backend": "Backend 2", "message": "Hello from Backend 2"}

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⚙️ Advanced Features

🛠 Health Check

The package automatically removes unhealthy backends from the rotation.

🚀 Rate Limiting (Optional)

To prevent abuse, you can enable rate limiting in loadbalancer.py.

⚡ Caching (Optional)

If you enable caching, the load balancer will store responses to reduce backend load.

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🎯 Why Use This?

• Easily distribute requests between multiple FastAPI backends.
• Automatic failover ensures high availability.
• Lightweight & easy to integrate with any FastAPI project.

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📜 License

This project is licensed under the MIT License.

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🤝 Contributing

1. Fork the repository.
2. Create a new branch (feature-new).
3. Commit changes and open a PR.

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📬 Need Help?

For issues, please open a GitHub Issue.

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⭐ Star this project if you find it useful! ⭐