Pass arguments to an app factory

[adamlwgriffiths]

I'm wanting to pass the path to a configuration file to my server via the cli.
My code looks something like this:

def create_app(config_filename):
    # make the app
    # configure myself
    return app

if __name__ == '__main__':
    uvicorn.run('my_app:create_app', factory=True, ...)

Ie. the app the builds and configures itself.

I'm simply wanting to pass arguments to the factory method that uvicorn calls.
I don't want uvicorn to attempt to load or parse these arguments.

I've looked around the documentation and in regards to configuration it's very unclear on how to do this.
There is mention of a --env-file via cli, and the Config class supports an env_file argument.
But both of these are parsed and somehow passed in.
I've already got a configuration file, I really don't want to write another one just as a way tell it to load the original.

How can I go about this?

[Kludex]

You can run uvicorn programmatically: https://www.uvicorn.org/#config-and-server-instances.

[adamlwgriffiths]

I've seen that page and it didn't appear to help as it doesn't demonstrate how to pass in arguments to an application factory function.
It instead implies that the function there must adhere to the (scope, receive, send) signature.

[JimiC]

The answer is you can't. Simply because it's not supported.

uvicorn/uvicorn/config.py

Line 440 in 3d26ab4

self.loaded_app = self.loaded_app()

You need to use a workaround. In my case I used manual dependencies creation.

Another solution could be using dependency injection via a DI package (like dependency-injector). Haven't tried it yet.