Python:using multiprocessing manager in process pool

Question

i use multiprocessing.managers.BaseManager to manager a Queue at server side,i try to use this queue in another python script which uses a process pool,but i always got the error message as follow, and the main code of this python script is as follow too, and it will start with the run() method.

File "/usr/lib/python2.7/multiprocessing/connection.py", line 435, in answer_challenge
    raise AuthenticationError('digest sent was rejected')
AuthenticationError: (AuthenticationError('digest sent was rejected',), <function RebuildProxy at 0x7ff8de0b8320>, (<function AutoProxy at 0x7ff8de0b7938>, Token(typeid='Queue', address=('localhost', 12345), id='7f4624039cd0'), 'pickle', {'exposed': ('cancel_join_thread', 'close', 'empty', 'full', 'get', 'get_nowait', 'join_thread', 'put', 'put_nowait', 'qsize')}))


def __init__(self, spider_count=cpu_count()):
    self._spider_count = spider_count
    mgr = MyManager(address=('localhost', 12345), authkey='xxxxx')
    server = mgr.connect()
    self._queue = mgr.Queue()

def run(self):
        pool = Pool(self._spider_count)
        while not self._queue.empty():
            #add some control on q.get() if queue is empty
            pool.apply_async(self.startCrawl, (self._queue.get(),))
        pool.close()
        pool.join()

but when i use it at a single thread, it works well, when use the pool, this error message raised.

Answer 1

This sounds like the issue described in http://bugs.python.org/issue7503

In practice all processes using the manager should have current_process().authkey set to the same value.

The fix, then, would be to assign in __init__ :

multiprocessing.current_process().authkey = 'xxxxx'