[FIXED] Fire coroutine from instide a for loop

Issue

I'm trying to fire a coroutine from within a loop. Here's a simple example of what I'm trying to achieve:

import time
import random
import asyncio


def listen():
    while True:
       yield random.random()
       time.sleep(3)


async def dosomething(data: float):
    print("Working on data", data)
    asyncio.sleep(2)
    print("Processed data!")


async def main():
    for pos in listen():
        asyncio.create_task(dosomething(pos))


if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.run_until_complete(main())

Unfortunately, this doesn't work and my dosomething coroutine never executes... what am I doing wrong?

Solution

asyncio.create_task function is aimed to schedule Task execution, it should be awaited to wait until it is complete.

Moreover, asyncio.sleep(2) in your code also should awaited, otherwise it'll throw an error/warning.

The right way:

import time
import random
import asyncio


def listen():
    while True:
       yield random.random()
       time.sleep(3)


async def dosomething(data: float):
    print("Working on data", data)
    await asyncio.sleep(2)
    print("Processed data!")


async def main():
    for pos in listen():
        await asyncio.create_task(dosomething(pos))


if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.run_until_complete(main())

Sample output:

Working on data 0.9645515392725723
Processed data!
Working on data 0.9249656672476657
Processed data!
Working on data 0.13635467058997397
Processed data!
Working on data 0.03941252405458562
Processed data!
Working on data 0.6299882183389822
Processed data!
Working on data 0.9143748948769984
Processed data!
...

Answered By - RomanPerekhrest