lesson06_wait_all.py

# SuperFastPython.com
# example of waiting for all tasks to complete
from time import sleep
from random import random
from concurrent.futures import ProcessPoolExecutor
from concurrent.futures import wait

# custom task function executed by a worker process
def task(number):
 # block for a fraction of a second
 sleep(random())
 # report value
 print(number, flush=True)

# protect the entry point
if __name__ == '__main__':
 # start the process pool
 with ProcessPoolExecutor(10) as exe:
 # issue all tasks and gather the futures
 futs = [exe.submit(task, i) for i in range(10)]
 # wait for all tasks to complete
 _ = wait(futs)
 # report a message
 print('All tasks are done!')