lesson02_initialize_processes.py

# SuperFastPython.com
# example initializing worker processes in the pool
from time import sleep
from concurrent.futures import ProcessPoolExecutor

# custom function to be executed in a worker process
def task(number):
 # report a message
 print(f'Worker task {number}...', flush=True)
 # block for a moment
 sleep(1)

# initialize a worker in the process pool
def init():
 # report a message
 print('Initializing worker...', flush=True)

# protect the entry point
if __name__ == '__main__':
 # create and configure the process pool
 with ProcessPoolExecutor(2,
 initializer=init) as exe:
 # issue tasks to the process pool
 _ = exe.map(task, range(4))