uASGI: A High-Performance ASGI Web Server

uASGI is a lightweight and efficient ASGI (Asynchronous Server Gateway Interface) web server for Python, designed for speed and flexibility. It supports only HTTP/1.1 protocols, with built-in SSL/TLS capabilities and a multiprocessing worker model for handling concurrent requests.

Inspired by the need for a simple yet powerful ASGI server, uASGI aims to provide a solid foundation for deploying asynchronous Python web applications.

Features

• ASGI Specification Compliance: Fully compatible with ASGI 2.0 and 3.0 applications (HTTP and Lifespan).
• HTTP/1.1 Support: Robust handling of HTTP/1.1 requests using httptools.
• SSL/TLS: Secure communication with built-in SSL context creation.
• Multiprocessing Workers: Scale your application across multiple CPU cores with a configurable worker pool.
• Asynchronous I/O: Built on asyncio and optimized with uvloop for high concurrency.

Installation

uASGI requires Python 3.13 or later.

You can install uASGI and its dependencies using pip or uv

pip install uasgi
uv add uasgi

Usage

Running a Simple ASGI Application

Here's how you can run a basic FastAPI application with uASGI.

First, create an example.py (or similar) file:

import os
from fastapi import FastAPI
from uasgi import run, create_logger
from contextlib import asynccontextmanager

logger = create_logger('app', 'INFO')

@asynccontextmanager
async def lifespan(_):
    logger.info('Application is starting...')
    yield {
        'property': 'value'
    }
    logger.info('Application is shutdown...')


def create_app():
    app = FastAPI(
        lifespan=lifespan,
    )

    @app.get('/')
    async def index():
        return {
            "Hello": "World"
        }

    return app


def main():
    run(
        app_factory=create_app, 
    )


if __name__ == '__main__':
    main()

Then, run it from your terminal:

python example.py

This will start the server on http://127.0.0.1:5000 with HTTP/1.1.

Configuration Options

The run function accepts several parameters to configure the server:

• app_factory: A callable that returns your ASGI application instance.
• host (str): The host address to bind to (default: '127.0.0.1').
• port (int): The port to listen on (default: 5000).
• backlog (int): The maximum number of pending connections (default: 1024).
• workers (int, optional): The number of worker processes to spawn. If None, runs in a single process.
• ssl_cert_file (str, optional): Path to the SSL certificate file.
• ssl_key_file (str, optional): Path to the SSL key file.
• log_level (str): Set the logging level ('DEBUG', 'INFO', 'WARNING', 'ERROR').

Development

To set up the development environment:

1. Clone the repository:

   git clone https://github.com/your-username/uasgi.git
   cd uasgi
   

2. Install dependencies:

   uv sync # or pip install -e .
   

Contributing

Contributions are welcome! Please see the CONTRIBUTING.md (to be created) for guidelines.

License

This project is licensed under the MIT License - see the LICENSE file for details.