Make a sync function async

run_in_executor.py

import asyncio
from functools import wraps, partial


def run_in_executor(fn=None, *, executor=None):
    """Make a sync function async. By default uses ThreadPoolExecutor."""
    if fn is None:
        # allow using this decorator with brackets, e.g.
        # @run_in_executor(executor=ThreadPoolExecutor(1))
        return partial(run_in_executor, executor=executor)

    @wraps(fn)
    async def wrapped(*args, **kwargs):
        """Wrap function in a run_in_executor."""
        _fn = partial(fn, *args, **kwargs)

        if hasattr(executor, "coro_apply"):
            # support aioprocessing.pool.AioPool
            fut = executor.coro_apply(_fn)
        else:
            fut = asyncio.get_running_loop().run_in_executor(executor, _fn)

        return await fut

    return wrapped


# without brackets
@run_in_executor
def test1():
    print(1)

await test1()


# with brackets
@run_in_executor()
def test2():
    print(2)

await test2()


# with explicit ThreadPoolExecutor
from concurrent.futures import ThreadPoolExecutor

@run_in_executor(executor=ThreadPoolExecutor(4))
def test3():
    print(3)

await test3()


# with explicit AioPool, patched using multiprocess (uses dill for universal pickling)
from aioprocessing.pool import AioPool
from multiprocess import Pool
setattr(AioPool, "delegate", Pool)

@run_in_executor(executor=AioPool(4))
def test4():
    print(4)

await test4()