How to run app from app factory?

I try to run the server by command uvicorn my_packege.app:create_app and got error: TypeError: __call__() missing 1 required positional argument: 'send'. What could be the reason?

[kristjanvalur]

application factories were added to flask due to the need to not having application creation a side effect of importing modules. It also allows having different versions/configurations of applications existing at the same time, which is great for unit tests. This pattern extends further, in that settings are typically stored as an object on the application itself, rather than statics in a settings module. Different settings can thus be created for different purposes, without having to restart the entire process. I am a bit surprised that this kind of pattern isn’t encouraged and supported by starlette / uvicorn, since it evolved as a response to a need.

[heckad]

I’m curious where the intent is coming from here, since Gunicorn doesn’t use an “app factory” style either. Is there a particular Python framework / server that you’re comparing this too?

flask, aiohttp

(I’m not totally against us having an invocation like that, but it’s not expected usage, and it’s not obvious that it’s required)

Factory need when you need test the app. If you use a global app then you get one app but in unit tests need to create an app for each test.