async VS uvicorn

There's an open discussion under the Uvicorn repository and we prepared a repository for Reproduction GitHub Repo

FastAPI is a popular Python Web framework that developers use to create RESTful APIs. It is based on Pydantic and Python-type hints that assist in the serialization, deserialization, and validation of data. In this tutorial, we will use FastAPI to create a simple "Hello World" application. We test and run the application locally. FastAPI requires a ASGI server to run the application production such as Uvicorn.

- [3] https://github.com/encode/uvicorn/issues/527

Uvicorn and Daphne are both ASGI server implementations that can be used with Django to serve your application using the ASGI protocol. Uvicorn is built on top of the uvloop library, which is a fast implementation of the event loop based on libuv, while Daphne is maintained as part of the Django Channels project and was designed to handle the unique requirements of Django applications that utilize asynchronous features, such as real-time updates, bidirectional communication, and long-lived connections.

So now we test if the application is working by running the application with uvicorn. Command has this format: uvicorn .:

Using a simple uvicorn hello world application, I was unable to replicate your case. Using the Dockerfile from your tutorial, and the example.py code from the uvicorn front page, along with your CMD, I got:

If you look at the printout after launching the app, you'll notice that Shiny is using Uvicorn under the hood. This is a common way of containerizing apps using FastAPI deployments.

You can scale with application server, by adding more processes to server requests. I use Gunicorn with Uvicorn workers.

There is also uvicorn

When writing a web app with FastAPI, using async/await and a library like uvicorn, the GIL is less of an issue as we are primarily IO bound.