lesson06_asyncresult.py

# SuperFastPython.com
# example check status and handle result of async task
from time import sleep
from random import random
from multiprocessing import Pool

# custom function to be executed in a child process
def task():
 # loop a few times to simulate a slow task
 for i in range(10):
 # generate a random value between 0 and 1
 value = random()
 # block for a fraction of a second
 sleep(value)
 # report a message
 print(f'>{i} got {value}', flush=True)

# protect the entry point
if __name__ == '__main__':
 # create the multiprocessing pool
 with Pool() as pool:
 # issue a task asynchronously
 async_result = pool.apply_async(task)
 # wait until the task is complete
 while not async_result.ready():
 # report a message
 print('Main process waiting...')
 # block for a moment
 async_result.wait(timeout=1)
 # report if the task was successful
 if async_result.successful():
 print('Task was successful.')