How to call asynchronous functions without expecting returns from them?

Question

In the code below I'd like to call task1 and task2 but WITHOUT expecting returns from these methods, is it possible?

import asyncio
async def say(something, delay):
  await asyncio.sleep(delay)
  print(something)

loop = asyncio.get_event_loop()
task1 = loop.create_task(say('hi', 1))
task2 = loop.create_task(say('hoi', 2))
loop.run_until_complete(asyncio.gather(task1, task2))

I would like to process something from a queue that gets to the main in a while loop, without waiting, because I do not need to return the functions, for example, a pseudo code:

import asyncio
async def say(something, delay):
  await asyncio.sleep(delay)
  print(something)

def main():
    while True:
        # search for database news
        # call say asynchronous, but I do not need any return, I just want you to do anything, independent
        time.sleep(1)

score 6 · Answer 1 · answered May 18 '19 at 16:42

If I understood you correctly, what you want you already have when you create task. Created task will be executed "in background": you don't have to await for it.

import asyncio


async def say(something, delay):
  await asyncio.sleep(delay)
  print(something)


async def main():
    # run tasks without awaiting for their results
    for i in range(5):
        asyncio.create_task(say(i, i))

    # do something while tasks running "in background"
    while True:
        print('Do something different')
        await asyncio.sleep(1)


asyncio.run(main())

Result:

Do something different
0
Do something different
1
2
Do something different
3
Do something different
4
Do something different
Do something different
Do something different
Do something different

How to call asynchronous functions without expecting returns from them?

1 Answers1