Merged revisions 80484 via svnmerge from

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........
  r80484 | antoine.pitrou | 2010-04-25 23:40:32 +0200 (dim., 25 avril 2010) | 6 lines

  Issue #2302: Fix a race condition in SocketServer.BaseServer.shutdown,
  where the method could block indefinitely if called just before the
  event loop started running.  This also fixes the occasional freezes
  witnessed in test_httpservers.
........
This commit is contained in:
Antoine Pitrou 2010-04-25 22:01:43 +00:00
parent a23831ff44
commit 3bcba8e288
3 changed files with 44 additions and 12 deletions

View File

@ -198,7 +198,7 @@ class BaseServer:
self.server_address = server_address self.server_address = server_address
self.RequestHandlerClass = RequestHandlerClass self.RequestHandlerClass = RequestHandlerClass
self.__is_shut_down = threading.Event() self.__is_shut_down = threading.Event()
self.__serving = False self.__shutdown_request = False
def server_activate(self): def server_activate(self):
"""Called by constructor to activate the server. """Called by constructor to activate the server.
@ -215,17 +215,19 @@ class BaseServer:
self.timeout. If you need to do periodic tasks, do them in self.timeout. If you need to do periodic tasks, do them in
another thread. another thread.
""" """
self.__serving = True
self.__is_shut_down.clear() self.__is_shut_down.clear()
while self.__serving: try:
# XXX: Consider using another file descriptor or while not self.__shutdown_request:
# connecting to the socket to wake this up instead of # XXX: Consider using another file descriptor or
# polling. Polling reduces our responsiveness to a # connecting to the socket to wake this up instead of
# shutdown request and wastes cpu at all other times. # polling. Polling reduces our responsiveness to a
r, w, e = select.select([self], [], [], poll_interval) # shutdown request and wastes cpu at all other times.
if r: r, w, e = select.select([self], [], [], poll_interval)
self._handle_request_noblock() if self in r:
self.__is_shut_down.set() self._handle_request_noblock()
finally:
self.__shutdown_request = False
self.__is_shut_down.set()
def shutdown(self): def shutdown(self):
"""Stops the serve_forever loop. """Stops the serve_forever loop.
@ -234,7 +236,7 @@ class BaseServer:
serve_forever() is running in another thread, or it will serve_forever() is running in another thread, or it will
deadlock. deadlock.
""" """
self.__serving = False self.__shutdown_request = True
self.__is_shut_down.wait() self.__is_shut_down.wait()
# The distinction between handling, getting, processing and # The distinction between handling, getting, processing and

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@ -241,6 +241,31 @@ class SocketServerTest(unittest.TestCase):
# socketserver.DatagramRequestHandler, # socketserver.DatagramRequestHandler,
# self.dgram_examine) # self.dgram_examine)
@reap_threads
def test_shutdown(self):
# Issue #2302: shutdown() should always succeed in making an
# other thread leave serve_forever().
class MyServer(socketserver.TCPServer):
pass
class MyHandler(socketserver.StreamRequestHandler):
pass
threads = []
for i in range(20):
s = MyServer((HOST, 0), MyHandler)
t = threading.Thread(
name='MyServer serving',
target=s.serve_forever,
kwargs={'poll_interval':0.01})
t.daemon = True # In case this function raises.
threads.append((t, s))
for t, s in threads:
t.start()
s.shutdown()
for t, s in threads:
t.join()
def test_main(): def test_main():
if imp.lock_held(): if imp.lock_held():

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@ -339,6 +339,11 @@ C-API
Library Library
------- -------
- Issue #2302: Fix a race condition in SocketServer.BaseServer.shutdown,
where the method could block indefinitely if called just before the
event loop started running. This also fixes the occasional freezes
witnessed in test_httpservers.
- Issue #8524: When creating an SSL socket, the timeout value of the - Issue #8524: When creating an SSL socket, the timeout value of the
original socket wasn't retained (instead, a socket with a positive timeout original socket wasn't retained (instead, a socket with a positive timeout
would be turned into a non-blocking SSL socket). would be turned into a non-blocking SSL socket).