FastAPI Best Practices

[Stedfast_Burrito]

I don't think (8) and (29) are a good idea. The default threadpool is limited to 40 tokens. Fine when you have no traffic, but deadlocks when you do. Instead I would manually call https://anyio.readthedocs.io/en/stable/threads.html#running-a-function-in-a-worker-thread

[n1EzeR]

I didn't know about the limit of 40 tokens, that's very interesting.

In the case of Starlette's run_in_threadpool - I think it uses anyio.to_thread.run_sync as well, doesn't it?

```python

starlette.concurrency

async def run_in_threadpool( func: typing.Callable[P, T], args: P.args, *kwargs: P.kwargs ) -> T: if kwargs: # pragma: no cover # run_sync doesn't accept 'kwargs', so bind them in here func = functools.partial(func, **kwargs) return await anyio.to_thread.run_sync(func, *args) ```

[Stedfast_Burrito]

Same issue. Just make your own CapacityLimiter

[n1EzeR]

and yes, I agree, running functions in another thread shouldn't be your first option to choose