Python multiprocessing exception handling

Given the following program structure I am looking for a way to:

• Detect child failures in the parent process

• Terminate all processes (parent and children) and exit with status code 1

• Achieve the above without relaxing the max queue size

Here's the code:

import multiprocessing


def worker1(queue1, queue2):
    while True:
        item = queue1.get()
        if item == 10:
            raise
        if item == 'stop':
            return
        # do something with item that generates multiple queue entries
        for x in xrange(1000):
            queue2.put(x)


def worker2(queue2, queue3):
    while True:
        item = queue2.get()
        if item == 'stop':
            return
        # do something with item, only one result to pass to the next queue
        queue3.put(1)


def worker3(queue3):
    while True:
        item = queue3.get()
        if item == 'stop':
            return
        # do something with item


def main():
    queue1 = multiprocessing.Queue()
    queue2 = multiprocessing.Queue(100)
    queue3 = multiprocessing.Queue(100)

    pool1 = multiprocessing.Pool(2, worker1, (queue1,queue2,))
    pool2 = multiprocessing.Pool(8, worker2, (queue2,queue3,))
    pool3 = multiprocessing.Pool(4, worker3, (queue3,))

    for i in xrange(100):
        queue1.put(i)
    for _ in range(pool1.__dict__['_processes']):
        queue1.put('stop')
    pool1.close()
    pool1.join()

    for _ in range(pool2.__dict__['_processes']):
        queue2.put('stop')
    pool2.close()
    pool2.join()

    for _ in range(pool3.__dict__['_processes']):
        queue3.put('stop')
    pool3.close()
    pool3.join()

    print 'finished'

if __name__ == '__main__':
    main()

Thanks!