Python: multiprocessing.map: If one process raises an exception, why aren't other processes' finally blocks called?

Question

My understanding is that finally clauses must *always* be executed if the try has been entered.

import random         


        

Answer 1

finally re-raises the original exception unless you return from it. The exception is then raised by Pool.map and kills your entire application. The subprocesses are terminated and you see no other exceptions.

You can add a return to swallow the exception:

def Process(x):
  try:
    print x
    sleep(random.random())
    raise Exception('Exception: ' + x)
  finally:
    print 'Finally: ' + x
    return

Then you should have None in your map result when an exception occurred.