1 #

     2 # Example where a pool of http servers share a single listening socket

     3 #

     4 # On Windows this module depends on the ability to pickle a socket

     5 # object so that the worker processes can inherit a copy of the server

     6 # object.  (We import `multiprocessing.reduction` to enable this pickling.)

     7 #

     8 # Not sure if we should synchronize access to `socket.accept()` method by

     9 # using a process-shared lock -- does not seem to be necessary.

    10 #

    11 

    12 import os

    13 import sys

    14 

    15 from multiprocessing import Process, current_process, freeze_support

    16 from BaseHTTPServer import HTTPServer

    17 from SimpleHTTPServer import SimpleHTTPRequestHandler

    18 

    19 if sys.platform == 'win32':

    20     import multiprocessing.reduction    # make sockets pickable/inheritable

    21 

    22 

    23 def note(format, *args):

    24     sys.stderr.write('[%s]\t%s\n' % (current_process().name, format%args))

    25 

    26 

    27 class RequestHandler(SimpleHTTPRequestHandler):

    28     # we override log_message() to show which process is handling the request

    29     def log_message(self, format, *args):

    30         note(format, *args)

    31 

    32 def serve_forever(server):

    33     note('starting server')

    34     try:

    35         server.serve_forever()

    36     except KeyboardInterrupt:

    37         pass

    38 

    39 

    40 def runpool(address, number_of_processes):

    41     # create a single server object -- children will each inherit a copy

    42     server = HTTPServer(address, RequestHandler)

    43 

    44     # create child processes to act as workers

    45     for i in range(number_of_processes-1):

    46         Process(target=serve_forever, args=(server,)).start()

    47 

    48     # main process also acts as a worker

    49     serve_forever(server)

    50 

    51 

    52 def test():

    53     DIR = os.path.join(os.path.dirname(__file__), '..')

    54     ADDRESS = ('localhost', 8000)

    55     NUMBER_OF_PROCESSES = 4

    56 

    57     print 'Serving at http://%s:%d using %d worker processes' % \

    58           (ADDRESS[0], ADDRESS[1], NUMBER_OF_PROCESSES)

    59     print 'To exit press Ctrl-' + ['C', 'Break'][sys.platform=='win32']

    60 

    61     os.chdir(DIR)

    62     runpool(ADDRESS, NUMBER_OF_PROCESSES)

    63 

    64 

    65 if __name__ == '__main__':

    66     freeze_support()

    67     test()