def listen(port=DEFAULT_LOGGING_CONFIG_PORT):
    """
    Start up a socket server on the specified port, and listen for new
    configurations.

    These will be sent as a file suitable for processing by fileConfig().
    Returns a Thread object on which you can call start() to start the server,
    and which you can join() when appropriate. To stop the server, call
    stopListening().
    """
    if not thread:
        raise NotImplementedError, "listen() needs threading to work"

    class ConfigStreamHandler(StreamRequestHandler):
        """
        Handler for a logging configuration request.

        It expects a completely new logging configuration and uses fileConfig
        to install it.
        """
        def handle(self):
            """
            Handle a request.

            Each request is expected to be a 4-byte length, packed using
            struct.pack(">L", n), followed by the config file.
            Uses fileConfig() to do the grunt work.
            """
            import tempfile
            try:
                conn = self.connection
                chunk = conn.recv(4)
                if len(chunk) == 4:
                    slen = struct.unpack(">L", chunk)[0]
                    chunk = self.connection.recv(slen)
                    while len(chunk) < slen:
                        chunk = chunk + conn.recv(len(chunk) - slen)
                    #Apply new configuration. We'd like to be able to
                    #create a StringIO and pass that in, but unfortunately
                    #1.5.2 ConfigParser does not support reading file
                    #objects, only actual files. So we create a temporary
                    #file and remove it later.
                    file = tempfile.mktemp(".ini")
                    f = open(file, "w")
                    f.write(chunk)
                    f.close()
                    try:
                        fileConfig(file)
                    except (KeyboardInterrupt, SystemExit):
                        raise
                    except:
                        traceback.print_exc()
                    os.remove(file)
            except socket.error, e:
                if type(e.args) != types.TupleType:
                    raise
                else:
                    errcode = e.args[0]
                    if errcode != RESET_ERROR:
                        raise

    class ConfigSocketReceiver(ThreadingTCPServer):
        """
        A simple TCP socket-based logging config receiver.
        """

        allow_reuse_address = 1

        def __init__(self, host='localhost', port=DEFAULT_LOGGING_CONFIG_PORT,
                     handler=None):
            ThreadingTCPServer.__init__(self, (host, port), handler)
            logging._acquireLock()
            self.abort = 0
            logging._releaseLock()
            self.timeout = 1

        def serve_until_stopped(self):
            import select
            abort = 0
            while not abort:
                rd, wr, ex = select.select([self.socket.fileno()],
                                           [], [],
                                           self.timeout)
                if rd:
                    self.handle_request()
                logging._acquireLock()
                abort = self.abort
                logging._releaseLock()

    def serve(rcvr, hdlr, port):
        server = rcvr(port=port, handler=hdlr)
        global _listener
        logging._acquireLock()
        _listener = server
        logging._releaseLock()
        server.serve_until_stopped()

    return threading.Thread(target=serve,
                            args=(ConfigSocketReceiver,
                                  ConfigStreamHandler, port))
dataset/ETHPy150Open babble/babble/include/jython/Lib/logging/config.py/listen/swapped operands of `-`