Using asyncio for Non-async Functions in Python?

Question

Suppose there is a library that makes various database queries:

import time

def queryFoo():
    time.sleep(4)
    return \"foo\"

def queryBar():
    time.s         


        

Answer 1

If some function is blocking and not async by nature, only proper way to run it inside asyncio event loop is to run it inside thread using run_in_executor:

# Our example blocking functions
import time


def queryFoo():
    time.sleep(3)
    return 'foo'


def queryBar():
    time.sleep(3)
    return 'bar'


# Run them using asyncio
import asyncio
from concurrent.futures import ThreadPoolExecutor


_executor = ThreadPoolExecutor(10)


async def in_thread(func):
    loop = asyncio.get_event_loop()
    return await loop.run_in_executor(_executor, func)


async def main():
    results = await asyncio.gather(
        in_thread(queryFoo), 
        in_thread(queryBar),
    )

    print(results)


if __name__ == "__main__":
    loop = asyncio.get_event_loop()
    try:
        loop.run_until_complete(main())
    finally:
        loop.run_until_complete(loop.shutdown_asyncgens())
        loop.close()

It does job.

If you however want to avoid using threads only way to do it - is to rewrite queryFoo/queryBar to be async by nature.