Multiprocessing in python - ensuring a minimum number of child processes are active
I want to ensure that a mininum number of child processes spawned are still active at any given time; the currently spawns as below:
pool = Pool(processes=WORKERS)
pool.map(worker.run, range(WORKERS)) # pass proc开发者_运维百科ess a number as its ID
There are certain cases where the workers would return
or crash and burn because of an error - i would like to spawn a new worker in this case. is this at all possible?
Thanks,
Here's a simple (dumb?) solution: periodically check all your workers, pop those that have returned and add new ones to the worker list (base code borrowed from Doug Hellman):
import multiprocessing, random, time
def worker(num):
"""thread worker function"""
time.sleep(random.randint(1,10))
print 'Worker:', num
return
if __name__ == '__main__':
jobs = []
for i in range(5):
p = multiprocessing.Process(target=worker, args=(i,))
jobs.append(p)
p.start()
while True:
time.sleep(2)
for n, p in enumerate(jobs):
if not p.is_alive():
jobs.pop(n)
i += 1
p = multiprocessing.Process(target=worker, args=(i,))
jobs.append(p)
p.start()
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