lesson03_map_timeout.py

# SuperFastPython.com
# example of executing tasks concurrently with timeout
from random import random
from time import sleep
from concurrent.futures import ProcessPoolExecutor
from concurrent.futures import TimeoutError

# custom function to be executed in a worker process
def task(number):
 # generate a random value between 0 and 1
 value = random()
 # report a message
 print(f'Task generated {value}', flush=True)
 # block for a moment to simulate work
 sleep(number + value)
 # return a new value
 return number + value

# protect the entry point
if __name__ == '__main__':
 # create the process pool
 with ProcessPoolExecutor(4) as exe:
 try:
 # issue tasks to execute concurrently
 for result in exe.map(task, range(10),
 timeout=2):
 # report results
 print(result)
 except TimeoutError:
 print('Gave up, took too long')
 # report that we will wait for the tasks to complete
 print('Waiting for tasks to complete...')