lesson04_barrier.py

# SuperFastPython.com
# example of using a barrier with threads
from time import sleep
from random import random
from threading import Thread
from threading import Barrier

# custom function to be executed in a new thread
def task(shared_barrier, ident):
 # generate a unique value between 0 and 10
 value = random() * 10
 # block for a moment
 sleep(value)
 # report result
 print(f'Thread {ident} got: {value}')
 # wait for all other threads to complete
 shared_barrier.wait()

# protect the entry point
if __name__ == '__main__':
 # create a barrier for (5 threads + 1 main thread)
 barrier = Barrier(5 + 1)
 # create the new threads
 threads = [Thread(target=task,
 args=(barrier, i)) for i in range(5)]
 # start the new threads
 for thread in threads:
 # start thread
 thread.start()
 # wait for all new threads to finish
 print('Main thread waiting on all results...')
 barrier.wait()
 # report once all thread are done
 print('All threads have their result')