<div dir="ltr">The connect method doesn't apear to return a connection...</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Aug 15, 2013 at 9:51 AM, Priyanki Vashi <span dir="ltr"><<a href="mailto:vashi.priyanki@gmail.com" target="_blank">vashi.priyanki@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi ,<div><br></div><div>on_connection_open, is a callback method, which will be called when connection is opened with rabbitmq. It opens channel inturn. So it's little unlikely that it has 'None' value but I am not 100% sure. </div>
<div><br></div><div>Here is my code. Could you quickly have a look.</div><div>It's the same example from pika site for tornado consumer except that I have tried to use connection parameters instead of URL.</div><div>
<br></div><div><br></div><div><div>from pika import adapters</div>
<div>import pika</div><div>import logging</div><div><br></div><div>LOG_FORMAT = ('%(levelname) -10s %(asctime)s %(name) -30s %(funcName) '</div><div> '-35s %(lineno) -5d: %(message)s')</div><div>
LOGGER = logging.getLogger(__name__)</div><div><br></div><div><br></div><div>class ExampleConsumer(object):</div><div> """This is an example consumer that will handle unexpected interactions</div><div> with RabbitMQ such as channel and connection closures.</div>
<div><br></div><div> If RabbitMQ closes the connection, it will reopen it. You should</div><div> look at the output, as there are limited reasons why the connection may</div><div> be closed, which usually are tied to permission related issues or</div>
<div> socket timeouts.</div><div><br></div><div> If the channel is closed, it will indicate a problem with one of the</div><div> commands that were issued and that should surface in the output as well.</div><div>
<br></div><div> """</div><div> EXCHANGE = 'message'</div><div> EXCHANGE_TYPE = 'topic'</div><div> QUEUE = 'text'</div><div> ROUTING_KEY = 'example.text'</div>
<div>
<br></div><div> </div><div> </div><div><br></div><div> def __init__(self, host, port, username, password):</div><div> """Setup the example publisher object, passing in the URL we will use</div>
<div> to connect to RabbitMQ.</div><div><br></div><div> :param str amqp_url: The URL for connecting to RabbitMQ</div><div><br></div><div> """</div><div> </div><div> self._connection = None</div>
<div> self._channel = None</div><div> self._closing = False</div><div> self._consumer_tag = None</div><div> #self._url = amqp_url</div><div> </div><div> self.credentials = pika.PlainCredentials(username=username, password=password)</div>
<div> self.parameters = pika.ConnectionParameters(host=host, port=port, credentials=self.credentials)</div><div> </div><div><br></div><div><br></div><div> def connect(self):</div><div> """This method connects to RabbitMQ, returning the connection handle.</div>
<div> When the connection is established, the on_connection_open method</div><div> will be invoked by pika.</div><div><br></div><div> :rtype: pika.SelectConnection</div><div><br></div><div> """</div>
<div> #LOGGER.info('Connecting to %s', self._url)</div><div> adapters.TornadoConnection(self.parameters, on_open_callback=self.on_connection_open, stop_ioloop_on_close=False)</div><div> #return adapters.TornadoConnection(pika.URLParameters(self._url),self.on_connection_open)</div>
<div><br></div><div> def close_connection(self):</div><div> """This method closes the connection to RabbitMQ."""</div><div> LOGGER.info('Closing connection')</div><div>
self._connection.close()</div><div><br></div><div> def add_on_connection_close_callback(self):</div><div> """This method adds an on close callback that will be invoked by pika</div><div> when RabbitMQ closes the connection to the publisher unexpectedly.</div>
<div><br></div><div> """</div><div> LOGGER.info('Adding connection close callback')</div><div> self._connection.add_on_close_callback(self.on_connection_closed)</div><div><br></div>
<div> def on_connection_closed(self, connection, reply_code, reply_text):</div><div> """This method is invoked by pika when the connection to RabbitMQ is</div><div> closed unexpectedly. Since it is unexpected, we will reconnect to</div>
<div> RabbitMQ if it disconnects.</div><div><br></div><div> :param pika.connection.Connection connection: The closed connection obj</div><div> :param int reply_code: The server provided reply_code if given</div>
<div> :param str reply_text: The server provided reply_text if given</div><div><br></div><div> """</div><div> self._channel = None</div><div> if self._closing:</div><div> self._connection.ioloop.stop()</div>
<div> else:</div><div> LOGGER.warning('Connection closed, reopening in 5 seconds: (%s) %s',</div><div> reply_code, reply_text)</div><div> self._connection.add_timeout(5, self.reconnect)</div>
<div><br></div><div> def on_connection_open(self, unused_connection):</div><div> """This method is called by pika once the connection to RabbitMQ has</div><div> been established. It passes the handle to the connection object in</div>
<div> case we need it, but in this case, we'll just mark it unused.</div><div><br></div><div> :type unused_connection: pika.SelectConnection</div><div><br></div><div> """</div><div>
LOGGER.info('Connection opened')</div><div> self.add_on_connection_close_callback()</div><div> self.open_channel()</div><div><br></div><div> def reconnect(self):</div><div> """Will be invoked by the IOLoop timer if the connection is</div>
<div> closed. See the on_connection_closed method.</div><div><br></div><div> """</div><div> # This is the old connection IOLoop instance, stop its ioloop</div><div> self._connection.ioloop.stop()</div>
<div><br></div><div> if not self._closing:</div><div><br></div><div> # Create a new connection</div><div> self._connection = self.connect()</div><div><br></div><div> # There is now a new connection, needs a new ioloop to run</div>
<div> self._connection.ioloop.start()</div><div><br></div><div> def add_on_channel_close_callback(self):</div><div> """This method tells pika to call the on_channel_closed method if</div>
<div> RabbitMQ unexpectedly closes the channel.</div><div><br></div><div> """</div><div> LOGGER.info('Adding channel close callback')</div><div> self._channel.add_on_close_callback(self.on_channel_closed)</div>
<div><br></div><div> def on_channel_closed(self, channel, reply_code, reply_text):</div><div> """Invoked by pika when RabbitMQ unexpectedly closes the channel.</div><div> Channels are usually closed if you attempt to do something that</div>
<div> violates the protocol, such as re-declare an exchange or queue with</div><div> different parameters. In this case, we'll close the connection</div><div> to shutdown the object.</div><div><br>
</div><div> :param pika.channel.Channel: The closed channel</div><div> :param int reply_code: The numeric reason the channel was closed</div><div> :param str reply_text: The text reason the channel was closed</div>
<div><br></div><div> """</div><div> LOGGER.warning('Channel %i was closed: (%s) %s',</div><div> channel, reply_code, reply_text)</div><div> self._connection.close()</div>
<div><br></div><div> def on_channel_open(self, channel):</div><div> """This method is invoked by pika when the channel has been opened.</div><div> The channel object is passed in so we can make use of it.</div>
<div><br></div><div> Since the channel is now open, we'll declare the exchange to use.</div><div><br></div><div> :param pika.channel.Channel channel: The channel object</div><div><br></div><div> """</div>
<div> LOGGER.info('Channel opened')</div><div> self._channel = channel</div><div> self.add_on_channel_close_callback()</div><div> self.setup_exchange(self.EXCHANGE)</div><div><br></div>
<div> def setup_exchange(self, exchange_name):</div><div> """Setup the exchange on RabbitMQ by invoking the Exchange.Declare RPC</div><div> command. When it is complete, the on_exchange_declareok method will</div>
<div> be invoked by pika.</div><div><br></div><div> :param str|unicode exchange_name: The name of the exchange to declare</div><div><br></div><div> """</div><div> LOGGER.info('Declaring exchange %s', exchange_name)</div>
<div> self._channel.exchange_declare(self.on_exchange_declareok,</div><div> exchange_name,</div><div> self.EXCHANGE_TYPE)</div><div><br></div>
<div> def on_exchange_declareok(self, unused_frame):</div><div> """Invoked by pika when RabbitMQ has finished the Exchange.Declare RPC</div><div> command.</div><div><br></div><div> :param pika.Frame.Method unused_frame: Exchange.DeclareOk response frame</div>
<div><br></div><div> """</div><div> LOGGER.info('Exchange declared')</div><div> self.setup_queue(self.QUEUE)</div><div><br></div><div> def setup_queue(self, queue_name):</div>
<div> """Setup the queue on RabbitMQ by invoking the Queue.Declare RPC</div><div> command. When it is complete, the on_queue_declareok method will</div><div> be invoked by pika.</div><div>
<br></div><div> :param str|unicode queue_name: The name of the queue to declare.</div><div><br></div><div> """</div><div> LOGGER.info('Declaring queue %s', queue_name)</div><div>
self._channel.queue_declare(self.on_queue_declareok, queue_name)</div><div><br></div><div> def on_queue_declareok(self, method_frame):</div><div> """Method invoked by pika when the Queue.Declare RPC call made in</div>
<div> setup_queue has completed. In this method we will bind the queue</div><div> and exchange together with the routing key by issuing the Queue.Bind</div><div> RPC command. When this command is complete, the on_bindok method will</div>
<div> be invoked by pika.</div><div><br></div><div> :param pika.frame.Method method_frame: The Queue.DeclareOk frame</div><div><br></div><div> """</div><div> LOGGER.info('Binding %s to %s with %s',</div>
<div> self.EXCHANGE, self.QUEUE, self.ROUTING_KEY)</div><div> self._channel.queue_bind(self.on_bindok, self.QUEUE,</div><div> self.EXCHANGE, self.ROUTING_KEY)</div>
<div><br></div><div> def add_on_cancel_callback(self):</div><div> """Add a callback that will be invoked if RabbitMQ cancels the consumer</div><div> for some reason. If RabbitMQ does cancel the consumer,</div>
<div> on_consumer_cancelled will be invoked by pika.</div><div><br></div><div> """</div><div> LOGGER.info('Adding consumer cancellation callback')</div><div> self._channel.add_on_cancel_callback(self.on_consumer_cancelled)</div>
<div><br></div><div> def on_consumer_cancelled(self, method_frame):</div><div> """Invoked by pika when RabbitMQ sends a Basic.Cancel for a consumer</div><div> receiving messages.</div><div>
<br></div><div> :param pika.frame.Method method_frame: The Basic.Cancel frame</div><div><br></div><div> """</div><div> LOGGER.info('Consumer was cancelled remotely, shutting down: %r',</div>
<div> method_frame)</div><div> if self._channel:</div><div> self._channel.close()</div><div><br></div><div> def acknowledge_message(self, delivery_tag):</div><div> """Acknowledge the message delivery from RabbitMQ by sending a</div>
<div> Basic.Ack RPC method for the delivery tag.</div><div><br></div><div> :param int delivery_tag: The delivery tag from the Basic.Deliver frame</div><div><br></div><div> """</div><div>
LOGGER.info('Acknowledging message %s', delivery_tag)</div><div> self._channel.basic_ack(delivery_tag)</div><div><br></div><div> def on_message(self, unused_channel, basic_deliver, properties, body):</div>
<div> """Invoked by pika when a message is delivered from RabbitMQ. The</div><div> channel is passed for your convenience. The basic_deliver object that</div><div> is passed in carries the exchange, routing key, delivery tag and</div>
<div> a redelivered flag for the message. The properties passed in is an</div><div> instance of BasicProperties with the message properties and the body</div><div> is the message that was sent.</div>
<div>
<br></div><div> :param pika.channel.Channel unused_channel: The channel object</div><div> :param pika.Spec.Basic.Deliver: basic_deliver method</div><div> :param pika.Spec.BasicProperties: properties</div>
<div> :param str|unicode body: The message body</div><div><br></div><div> """</div><div> LOGGER.info('Received message # %s from %s: %s',</div><div> basic_deliver.delivery_tag, properties.app_id, body)</div>
<div> self.acknowledge_message(basic_deliver.delivery_tag)</div><div><br></div><div> def on_cancelok(self, unused_frame):</div><div> """This method is invoked by pika when RabbitMQ acknowledges the</div>
<div> cancellation of a consumer. At this point we will close the channel.</div><div> This will invoke the on_channel_closed method once the channel has been</div><div> closed, which will in-turn close the connection.</div>
<div><br></div><div> :param pika.frame.Method unused_frame: The Basic.CancelOk frame</div><div><br></div><div> """</div><div> LOGGER.info('RabbitMQ acknowledged the cancellation of the consumer')</div>
<div> self.close_channel()</div><div><br></div><div> def stop_consuming(self):</div><div> """Tell RabbitMQ that you would like to stop consuming by sending the</div><div> Basic.Cancel RPC command.</div>
<div><br></div><div> """</div><div> if self._channel:</div><div> LOGGER.info('Sending a Basic.Cancel RPC command to RabbitMQ')</div><div> self._channel.basic_cancel(self.on_cancelok, self._consumer_tag)</div>
<div><br></div><div> def start_consuming(self):</div><div> """This method sets up the consumer by first calling</div><div> add_on_cancel_callback so that the object is notified if RabbitMQ</div>
<div> cancels the consumer. It then issues the Basic.Consume RPC command</div><div> which returns the consumer tag that is used to uniquely identify the</div><div> consumer with RabbitMQ. We keep the value to use it when we want to</div>
<div> cancel consuming. The on_message method is passed in as a callback pika</div><div> will invoke when a message is fully received.</div><div><br></div><div> """</div><div> LOGGER.info('Issuing consumer related RPC commands')</div>
<div> self.add_on_cancel_callback()</div><div> self._consumer_tag = self._channel.basic_consume(self.on_message,</div><div> self.QUEUE)</div><div><br>
</div>
<div> def on_bindok(self, unused_frame):</div><div> """Invoked by pika when the Queue.Bind method has completed. At this</div><div> point we will start consuming messages by calling start_consuming</div>
<div> which will invoke the needed RPC commands to start the process.</div><div><br></div><div> :param pika.frame.Method unused_frame: The Queue.BindOk response frame</div><div><br></div><div> """</div>
<div> LOGGER.info('Queue bound')</div><div> self.start_consuming()</div><div><br></div><div> def close_channel(self):</div><div> """Call to close the channel with RabbitMQ cleanly by issuing the</div>
<div> Channel.Close RPC command.</div><div><br></div><div> """</div><div> LOGGER.info('Closing the channel')</div><div> self._channel.close()</div><div><br></div><div> def open_channel(self):</div>
<div> """Open a new channel with RabbitMQ by issuing the Channel.Open RPC</div><div> command. When RabbitMQ responds that the channel is open, the</div><div> on_channel_open callback will be invoked by pika.</div>
<div><br></div><div> """</div><div> LOGGER.info('Creating a new channel')</div><div> self._connection.channel(on_open_callback=self.on_channel_open)</div><div><br></div><div> def run(self):</div>
<div> """Run the example consumer by connecting to RabbitMQ and then</div><div> starting the IOLoop to block and allow the SelectConnection to operate.</div><div><br></div><div> """</div>
<div> self._connection = self.connect()</div><div> self._connection.ioloop.start()</div><div><br></div><div> def stop(self):</div><div> """Cleanly shutdown the connection to RabbitMQ by stopping the consumer</div>
<div> with RabbitMQ. When RabbitMQ confirms the cancellation, on_cancelok</div><div> will be invoked by pika, which will then closing the channel and</div><div> connection. The IOLoop is started again because this method is invoked</div>
<div> when CTRL-C is pressed raising a KeyboardInterrupt exception. This</div><div> exception stops the IOLoop which needs to be running for pika to</div><div> communicate with RabbitMQ. All of the commands issued prior to starting</div>
<div> the IOLoop will be buffered but not processed.</div><div><br></div><div> """</div><div> LOGGER.info('Stopping')</div><div> self._closing = True</div><div> self.stop_consuming()</div>
<div> self._connection.ioloop.start()</div><div> LOGGER.info('Stopped')</div><div><br></div><div><br></div><div>def main():</div><div> logging.basicConfig(level=logging.INFO, format=LOG_FORMAT)</div>
<div> example = ExampleConsumer('mqserver10', 5672, 'guest', 'guest')</div><div> try:</div><div> example.run()</div><div> except KeyboardInterrupt:</div><div> example.stop()</div>
<div><br></div><div><br></div><div>if __name__ == '__main__':</div><div> main()</div></div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Aug 15, 2013 at 3:25 PM, Ask Solem <span dir="ltr"><<a href="mailto:ask@rabbitmq.com" target="_blank">ask@rabbitmq.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><br>
On Aug 15, 2013, at 1:20 PM, Priyanki Vashi <<a href="mailto:vashi.priyanki@gmail.com" target="_blank">vashi.priyanki@gmail.com</a>> wrote:<br>
<br>
> Hi There ,<br>
><br>
> This might be very basic error but since I am trying to use Tornado connection for the first time, help on this would be appreciated.<br>
><br>
> I was trying to use Tornado consumer example given on following pika site.<br>
><br>
> <a href="https://pika.readthedocs.org/en/0.9.13/examples/tornado_consumer.html" target="_blank">https://pika.readthedocs.org/en/0.9.13/examples/tornado_consumer.html</a><br>
><br>
> I am running into following error. The example is with URL connection method.<br>
> But I also tried to use hostname and port method as well as tried changing to IP address instead of hostname but still it's the same error.<br>
><br>
> I have pika 0.9.13 library installed. My consumer & Producer works fine with select.connection method so I believe library is correctly installed.<br>
><br>
> Do I need to do something additional to get tornado connection working for both producer and consumer with pika?<br>
><br>
> Please suggest.<br>
><br>
> mq1@mqserver1:~/Producer_Receiver/Latest$ python tornedo_c_1.py<br>
> Traceback (most recent call last):<br>
> File "tornedo_c_1.py", line 357, in <module><br>
> main()<br>
> File "tornedo_c_1.py", line 351, in main<br>
> example.run()<br>
> File "tornedo_c_1.py", line 326, in run<br>
> self._connection = self.connect()<br>
> File "tornedo_c_1.py", line 59, in connect<br>
> adapters.TornadoConnection(self.parameters, self.on_connection_open, stop_ioloop_on_close=False)<br>
> TypeError: 'NoneType' object is not callable<br>
<br>
<br>
</div></div>Maybe you passed None as a callback somewhere? What is the value of on_connection_open for example?<br>
<br>
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