Propagate KeyBoardInterrupt up to main thread.

[calum-chamberlain]

Is your feature request related to a problem? Please describe.

Say something is awry with you code and you want to stop it (using ctrl-C on Linux), if EQcorrscan is in a multiprocessing loop, the KeyBoardInterrupt signal only kills one working thread, and another takes its place, rather than stopping the program. It would be good to propagate this up and actually stop the program (@nackerley requested this).

Describe the solution you'd like

Reading around this shouldn't be too hard, following something like this example (copied from here:

import multiprocessing, os, time

def do_work(i):
    try:
        print 'Work Started: %d %d' % (os.getpid(), i)
        time.sleep(2)
        return 'Success'
    except KeyboardInterrupt, e:
        pass

def main():
    pool = multiprocessing.Pool(3)
    p = pool.map_async(do_work, range(6))
    try:
        results = p.get(0xFFFF)
    except KeyboardInterrupt:
        print 'parent received control-c'
        return

Describe alternatives you've considered

None, and this is really just a nicety, at the moment I kill things from htop and it is quite clumsy.

[calum-chamberlain]

More useful Python 3 example:

import multiprocessing, os, time

def do_work(i):
    try:
        print('Work Started: {0} {1}'.format(os.getpid(), i))
        time.sleep(20)
        return 'Success'
    except KeyboardInterrupt as e:
        print("KeyBoardInterrupt on {0}".format(os.getpid()))
        pass

if __name__ == "__main__":
    pool = multiprocessing.Pool(3)
    p = pool.map_async(do_work, range(6))
    try:
        results = p.get(0xFFFF)
    except KeyboardInterrupt:
        print('parent received control-c')
        pool.terminate()
    pool.join()
    pool.close()