use-pool.py

#!/usr/bin/env python
"""
http://stackoverflow.com/questions/20167735/python-multiprocessing-pipe-deadlock
"""
import logging
import multiprocessing as mp

def process(item):
    print("adding ", item, "to done queue")
    return item*100000

def main():
    mp.log_to_stderr().setLevel(logging.DEBUG)
    pool = mp.Pool(processes=4)
    items = ("hi"+str(x) for x in range(10))
    for result in pool.imap_unordered(process, items, chunksize=2):
        print(len(result))
    pool.close()
    pool.join()

if __name__ == '__main__':
    mp.freeze_support()
    main()