multiproc+vars.py

# variable scope, lifetime

# modified from stackoverflow https://goo.gl/Gy5Ai7
import multiprocessing
import os


def hey(pid, message):
  global i
  global queue
  denominator = None
  try:
    denominator = queue.qsize()
  except NameError:
    pass
  print(
    '{}:{}/{}'.format(pid, i, denominator),
    message,
  )
  i += 1


def worker_main(queue):
  hey(os.getpid(), 'init')
  while True:
    item = queue.get(True)
    hey(os.getpid(), item)


i = 0
hey(os.getpid(), 'BEFORE')
queue = multiprocessing.Queue()
pool = multiprocessing.Pool(processes=3, initializer=worker_main, initargs=(queue, ))

for i in range(5):
  queue.put('hello')
  queue.put('world')

hey(os.getpid(), 'DURING')

while queue.qsize():
  pass

hey(os.getpid(), 'AFTER')
#