Tornado not running callback

Question

This is very simple client for tcp-chat. This is main function:

@gen.coroutine
def main():
    factory = TCPClient()
    stream = yield factory.connect(af=socket.AF_INET, **options.options.group_dict("connect"))
    # Add notification callback
    ioloop.IOLoop.instance().add_callback(notification, stream)
    # Run application
    app = Application(stream)
    app.run()

if __name__ == '__main__':
    try:
        main()
        ioloop.IOLoop.instance().start()
    except KeyboardInterrupt:
        pass

Application is running. App read data from console, send it into socket. Main loop of application:

@gen.coroutine
def run(self):
    while True:
        try:
            s = input('> ')
            command, text = self._parse_command(s)
            handler = self.handler(self._stream, self)
            yield handler.execute_command(command, text)
        except Exception as e:
            print(e)

And i have console notification. This function read response from socket and print into console:

@gen.coroutine
def notification(stream):
    message_length = yield stream.read_bytes(2)
    length = struct.unpack("!H", message_length)[0]
    message = yield stream.read_bytes(length)
    # request = Message.unpack(message=message)
    sys.stdout.write('\r'+' '*(len(readline.get_line_buffer())+2)+'\r')
    print(message)
    sys.stdout.write('> ' + readline.get_line_buffer())
    sys.stdout.flush()
    ioloop.IOLoop.instance().add_callback(notification, stream)

I add this function as callback into ioloop. But this function is never running. How run notification in background? Help my please...

UPD: I create new thread and run notification in new thread:

th = threading.Thread(target=notification, args=(self._stream, ))
th.run()

But it did not help...

Answer 1

input() is a blocking function; nothing else can happen while it is waiting for input. In order for the application to be responsive you must rework it to avoid blocking functions like input() , or to perform those functions on a separate thread.