[QUESTION] How to use with async?

[csheppard]

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Description

I have existing methods/model functions that use async functions with encode/databases to load data but I'm unable to use these within commands without getting errors such as RuntimeWarning: coroutine 'something' was never awaited

How can I make make my @app.command() functions async friendly?

[csheppard]

Just found pallets/click#85 (comment) which may help me

[mreschke]

Seeing as how FastAPI is an async framework, having an async CLI seems logical. The main reason being sharing code from the CLI and Web entry points. You can of course use the asgiref.sync.async_to_sync converter helpers to call existing async methods from the CLI but there are complications here and it makes your cli code clunky. I replaced typer with smurfix/trio-click (which is asyncclick on Pypi) and it works great, but of course this is just async click, not the cool typer implementation. Forking typer and replaceing all import click with import asyncclick as click works like a charm but it means maintenance of the fork yourself. If @smurfix could keep his async fork maintained and up to date with click upstream, and if typer was based on asyncclick then we would really have something great here.

[smurfix]

I will update asyncclick to the latest click release as soon as anyio 2.0 is ready.

[mreschke]

Thanks @smurfix. Once you have asyncclick updated, if @tiangolo doesn't have a nice async typer by then, perhaps ill make a good typer-async fork of typer and use asyncclick and add to pypi for us all to use.

[jessekrubin]

Thanks @smurfix. Once you have asyncclick updated, if @tiangolo doesn't have a nice async typer by then, perhaps ill make a good typer-async fork of typer and use asyncclick and add to pypi for us all to use.

@mreschke I made a pull request to this repo that gets you most of the way to async. #128

[amfarrell]

@mreschke I've updated @jessekrubin's PR to remove the conflicts with master, in case you find it useful.

[mreschke]

Thanks guys. Ill need some time to pull it all in and prototype this instead of asyncclick. If this all works out what is the probability of merging this request and making it a part of this official typer repo. Optional async would be perfect. I really hate to fork permanently.

[elpapi42]

We all need this

[killswitch-GUI]

I agree with @mreschke, we tightly couple all of our code and actually use Type CLI to call our uvicorn/guinicorn using various "management" commands. Ran into this once we wanted to use some of the async calls we have.

[neimad1985]

Hi :)
Anything new on this ?

[jessekrubin]

Hi :)
Anything new on this ?

@neimad1985 I don't think async is PR-ed in yet, but I use async with typer all the time by just running the async processes from within my sync functions once the parsing is done. It works for most basic things.

[neimad1985]

Thanks for the quick answer @jessekrubin
Would it be possible that you share a simple code example on how you do this please ?

[jessekrubin]

@neimad1985

from asyncio import run as aiorun

import typer


async def _main(name: str):
    typer.echo(f"Hello {name}")

def main(name: str = typer.Argument("Wade Wilson")):
    aiorun(_main(name=name))


if __name__ == "__main__":
    typer.run(main)

[neimad1985]

@jessekrubin

Ok thanks, that's exactly what I was thinking.
The problem is the duplication of functions main and _main and their arguments.
If you have multiple subcommands, which I have, for your program you have more and more duplication.
Anyway thanks for answering me.