Simple tornado web server with rabbitmq's pika

tornado pika example.py

import tornado.ioloop
import tornado.web
import pika
import logging
from pika.adapters.tornado_connection import TornadoConnection

TORNADO_PORT = 8889

RMQ_USER = 'user'
RMQ_PWD = 'password'
RMQ_HOST = 'localhost'
RMQ_PORT = 5762

IOLOOP_TIMEOUT = 500

logger = logging.getLogger()

# Holds channel objects
channel = None

class PikaClient(object):
    # All the following functions precede in order starting with connect
    def connect(self):
        try:
            logger = logging.getLogger('rmq_tornado')
            credentials = pika.PlainCredentials(RMQ_USER, RMQ_PWD)
            param = pika.ConnectionParameters(host=RMQ_HOST, port=RMQ_PORT, credentials=credentials)

            self.connection = TornadoConnection(param, on_open_callback=self.on_connected)
        except Exception as e:
            logger.error('Something went wrong... %s', e)

    def on_connected(self, connection):
        """When we are completely connected to rabbitmq this is called"""

        logger.info('Succesfully connected to rabbitmq')

        # Open a channel
        self.connection.channel(self.on_channel_open)

    def on_channel_open(self, new_channel):
        """When the channel is open this is called"""
        logging.info('Opening channel to rabbitmq')

        global channel
        channel = new_channel

class Application(tornado.web.Application):
    def __init__(self):
        handlers = [
                    (r"/", MainHandler),
        ]

        tornado.web.Application.__init__(self, handlers)
 
class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Tornado web server.  Post a message to it using 'message' as a parameter. \
                The message will then be published to a rabbitmq queue.")

    def post(self):
        try:
            rcv_message = self.get_argument('message', 'The received message had no content.')

            logging.info('About to send received message to rabbitmq exchange %s', rcv_message)

            channel.basic_publish(exchange='', routing_key='my_queue_name', properties=pika.BasicProperties(content_type='application/text'), body=rcv_message)
        except Exception as e:
            logger.error('Something went wrong... %s', e)

application = Application()

if __name__ == "__main__":
    application.pika = PikaClient()

    application.listen(TORNADO_PORT)

    ioloop = tornado.ioloop.IOLoop.instance()

    ioloop.add_timeout(IOLOOP_TIMEOUT, application.pika.connect)

    ioloop.start()