Async.IO Example #2: Run 10 parallel tasks - But returning some results before all tasks to be done

asyncio_example2_as_completed.py

import asyncio
from random import randint


async def execute_your_task(task_number: int):
    """ Specific task to run in parallel """
    
    # display begin of parallel task in console
    print('-> starting parallel task:', task_number)
    
    # sleeping by (randomly: between 1 and 5 seconds) just to see parallism working
    seconds_to_sleep = randint(1, 5)
    await asyncio.sleep(seconds_to_sleep)
    
    # display end of parallel task in console
    print('<- finishing parallel task:', task_number)

    # return task information in a dict
    return {'task_number': task_number, 'seconds_to_sleep': seconds_to_sleep}
    

async def running_parallel_tasks():
    """ Running 10 parallel tasks - returning parcial results before all tasks to be done """
    
    # define a list with 10 coroutine tasks to be run
    tasklist_to_run = []
    for n in range(1, 11):
        coroutine_of_task = execute_your_task(n)
        tasklist_to_run.append(coroutine_of_task)

    # run 10 coroutine tasks in parallel but already returning results
    task_results = []
    for task_coroutine in asyncio.as_completed(tasklist_to_run):
        # await coroutine of task to get result
        task_result = await task_coroutine
    
        # display result and return
        print('! received task result', task_result)
        task_results.append(task_result)

    return task_results

# Running running_parallel_tasks as asynchronous mode
asyncio.run(running_parallel_tasks())

# Execution example:
"""
In [1]: asyncio.run(running_parallel_tasks())
-> starting parallel task: 10
-> starting parallel task: 8
-> starting parallel task: 5
-> starting parallel task: 9
-> starting parallel task: 2
-> starting parallel task: 6
-> starting parallel task: 7
-> starting parallel task: 1
-> starting parallel task: 3
-> starting parallel task: 4
<- finishing parallel task: 8
<- finishing parallel task: 4
! received task result {'task_number': 8, 'seconds_to_sleep': 1}
! received task result {'task_number': 4, 'seconds_to_sleep': 1}
<- finishing parallel task: 1
! received task result {'task_number': 1, 'seconds_to_sleep': 2}
<- finishing parallel task: 10
<- finishing parallel task: 6
<- finishing parallel task: 7
<- finishing parallel task: 3
! received task result {'task_number': 10, 'seconds_to_sleep': 3}
! received task result {'task_number': 6, 'seconds_to_sleep': 3}
! received task result {'task_number': 7, 'seconds_to_sleep': 3}
! received task result {'task_number': 3, 'seconds_to_sleep': 3}
<- finishing parallel task: 5
<- finishing parallel task: 9
<- finishing parallel task: 2
! received task result {'task_number': 5, 'seconds_to_sleep': 4}
! received task result {'task_number': 9, 'seconds_to_sleep': 4}
! received task result {'task_number': 2, 'seconds_to_sleep': 4}
Out[1]: 
[{'task_number': 8, 'seconds_to_sleep': 1},
 {'task_number': 4, 'seconds_to_sleep': 1},
 {'task_number': 1, 'seconds_to_sleep': 2},
 {'task_number': 10, 'seconds_to_sleep': 3},
 {'task_number': 6, 'seconds_to_sleep': 3},
 {'task_number': 7, 'seconds_to_sleep': 3},
 {'task_number': 3, 'seconds_to_sleep': 3},
 {'task_number': 5, 'seconds_to_sleep': 4},
 {'task_number': 9, 'seconds_to_sleep': 4},
 {'task_number': 2, 'seconds_to_sleep': 4}]
"""