[Python-Dev] Re: Integrating timeoutsocket.py (original) (raw)

Michael Gilfix mgilfix@eecs.tufts.edu
Sat, 27 Apr 2002 19:15:08 -0400

Gonna carbon the dev list to get people's opinions on this one. Something definitely needs to change in the way ServerSocket.py is implemented.

Found the cause in ServerSocket.py. You need to add the line:

t.setDaemon (1)

at line 469 in ServerSocket.py, right after the thread is created. Whether this is an error is debatable though. The problem is that the other threads don't know you're exiting, so they continue running after you exit. Ideally, we should either just set the client threads as daemon threads or we should have some way of signaling them that they must terminate. One solution without touching ServerSocket is to subclass off of ThreadingMixIn and create a new ThreadingTCPServer class. Not too elegant though.

The docs for the thread module say:

"Threads interact strangely with interrupts: the KeyboardInterrupt exception will be received by an arbitrary thread. (When the signal module is available, interrupts always go to the main thread.)"

Kinda unfortunate in this scenario.

                -- Mike

On Sat, Apr 27 @ 12:44, Bernard Yue wrote:

About the test. I am facing this problem with Threading server (using SocketServer module). The new socket module somehow change the behavior of the threading server. The change happens during server exit.

With the old module, when there is are client(s) connected to the server, existing the server by KeyboardInterrupt will close the connection with all the connecting client. Not the case for the new module. The thread which serving a connected client will stays on until the client exit. I am not exactly sure why it happens. Attached is the script, use telnet client to do the test and see if you can figure out why.

Bernie =================================================================== #!/usr/bin/env python '#!/home/bernie/src/python23/dist/src/python'

import time import select import SocketServer

class RequestHandler( SocketServer.StreamRequestHandler): def init(self, request, client_address, server): SocketServer.StreamRequestHandler.init(self, request, client_address, server)

def handle( self):
    """Handle a client"""
    _remote_id = '%s:%s' % self.request.getpeername()
    print 'Client %s connected' % _remote_id
    self.wfile.write( 'Hello %s\n' % _remote_id)

    while 1:
        select.select( [self.rfile.fileno()], [], [])
        try:
            _in = self.rfile.readline()
            if not self.process_command( _in, _remote_id):
                break
        except IOError:
            break    # connection reset by requester

    print '%s quited' % _remote_id

def process_command( self, command, client='anonymous'):
    _command = command.strip()
    if _command == 'exit' or not command:
        return 0

    if _command:
        print 'Request from %s: [%s]' % (client, _command)
        self.wfile.write( 'Command [%s] received!\n' % _command)
        self.wfile.flush()

    return 1

class MyTCPServer( SocketServer.TCPServer): def init( self, server_address, RequestHandlerClass, timeout=None): self.__timeout = timeout SocketServer.TCPServer.init( self, server_address, RequestHandlerClass)

    '''
    # set timeout
    if self.__timeout:
        try:
            print 'Set timeout to %s second(s)' % self.socket.gettimeout()
            print 'Current time is %s' % time.asctime()
            self.socket.settimeout( self.__timeout)
        except AttributeError:
            print 'No timeout with socket'
    '''

class ThreadingTCPServer( SocketServer.ThreadingMixIn, MyTCPServer): pass

def main( argv): if len(argv) == 1: print 'Usage server.py ' return 0

_address = ( argv[1], int(argv[2]))
_server = ThreadingTCPServer( _address, RequestHandler, 3)

try:
    _server.serve_forever()
except KeyboardInterrupt:
    _server.server_close()
    print "Server Terminated!"

if name == "main": import sys main( sys.argv)

-- Michael Gilfix mgilfix@eecs.tufts.edu

For my gpg public key: http://www.eecs.tufts.edu/~mgilfix/contact.html