/Doc/includes/mp_webserver.py

 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# Copyright (c) 2006-2008, R Oudkerk
12# All rights reserved.
13#
14
15import os
16import sys
17
18from multiprocessing import Process, current_process, freeze_support
19from BaseHTTPServer import HTTPServer
20from SimpleHTTPServer import SimpleHTTPRequestHandler
21
22if sys.platform == 'win32':
23    import multiprocessing.reduction    # make sockets pickable/inheritable
24
25
26def note(format, *args):
27    sys.stderr.write('[%s]\t%s\n' % (current_process().name, format%args))
28
29
30class RequestHandler(SimpleHTTPRequestHandler):
31    # we override log_message() to show which process is handling the request
32    def log_message(self, format, *args):
33        note(format, *args)
34
35def serve_forever(server):
36    note('starting server')
37    try:
38        server.serve_forever()
39    except KeyboardInterrupt:
40        pass
41
42
43def runpool(address, number_of_processes):
44    # create a single server object -- children will each inherit a copy
45    server = HTTPServer(address, RequestHandler)
46
47    # create child processes to act as workers
48    for i in range(number_of_processes-1):
49        Process(target=serve_forever, args=(server,)).start()
50
51    # main process also acts as a worker
52    serve_forever(server)
53
54
55def test():
56    DIR = os.path.join(os.path.dirname(__file__), '..')
57    ADDRESS = ('localhost', 8000)
58    NUMBER_OF_PROCESSES = 4
59
60    print 'Serving at http://%s:%d using %d worker processes' % \
61          (ADDRESS[0], ADDRESS[1], NUMBER_OF_PROCESSES)
62    print 'To exit press Ctrl-' + ['C', 'Break'][sys.platform=='win32']
63
64    os.chdir(DIR)
65    runpool(ADDRESS, NUMBER_OF_PROCESSES)
66
67
68if __name__ == '__main__':
69    freeze_support()
70    test()