[rabbitmq-discuss] Tornado Consumer example problem
Priyanki Vashi
vashi.priyanki at gmail.com
Thu Aug 15 16:00:44 BST 2013
Hi,
Sorry to say but I have now made connection to return the value but it
still say the same error.
Does anyone have working example of tornado connector (either consumer or
producer) with pika client and has possibility to sharing with me ?
Very basic example is also OK.
Thank you in advance !
Best Regards,
Priyanki.
On Thu, Aug 15, 2013 at 4:25 PM, Laing, Michael
<michael.laing at nytimes.com>wrote:
> The connect method doesn't apear to return a connection...
>
>
> On Thu, Aug 15, 2013 at 9:51 AM, Priyanki Vashi <vashi.priyanki at gmail.com>wrote:
>
>> Hi ,
>>
>> 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.
>>
>> Here is my code. Could you quickly have a look.
>> It's the same example from pika site for tornado consumer except that I
>> have tried to use connection parameters instead of URL.
>>
>>
>> from pika import adapters
>> import pika
>> import logging
>>
>> LOG_FORMAT = ('%(levelname) -10s %(asctime)s %(name) -30s %(funcName) '
>> '-35s %(lineno) -5d: %(message)s')
>> LOGGER = logging.getLogger(__name__)
>>
>>
>> class ExampleConsumer(object):
>> """This is an example consumer that will handle unexpected
>> interactions
>> with RabbitMQ such as channel and connection closures.
>>
>> If RabbitMQ closes the connection, it will reopen it. You should
>> look at the output, as there are limited reasons why the connection
>> may
>> be closed, which usually are tied to permission related issues or
>> socket timeouts.
>>
>> If the channel is closed, it will indicate a problem with one of the
>> commands that were issued and that should surface in the output as
>> well.
>>
>> """
>> EXCHANGE = 'message'
>> EXCHANGE_TYPE = 'topic'
>> QUEUE = 'text'
>> ROUTING_KEY = 'example.text'
>>
>>
>>
>>
>> def __init__(self, host, port, username, password):
>> """Setup the example publisher object, passing in the URL we will
>> use
>> to connect to RabbitMQ.
>>
>> :param str amqp_url: The URL for connecting to RabbitMQ
>>
>> """
>>
>> self._connection = None
>> self._channel = None
>> self._closing = False
>> self._consumer_tag = None
>> #self._url = amqp_url
>>
>> self.credentials = pika.PlainCredentials(username=username,
>> password=password)
>> self.parameters = pika.ConnectionParameters(host=host, port=port,
>> credentials=self.credentials)
>>
>>
>>
>> def connect(self):
>> """This method connects to RabbitMQ, returning the connection
>> handle.
>> When the connection is established, the on_connection_open method
>> will be invoked by pika.
>>
>> :rtype: pika.SelectConnection
>>
>> """
>> #LOGGER.info('Connecting to %s', self._url)
>> adapters.TornadoConnection(self.parameters,
>> on_open_callback=self.on_connection_open, stop_ioloop_on_close=False)
>> #return
>> adapters.TornadoConnection(pika.URLParameters(self._url),self.on_connection_open)
>>
>> def close_connection(self):
>> """This method closes the connection to RabbitMQ."""
>> LOGGER.info('Closing connection')
>> self._connection.close()
>>
>> def add_on_connection_close_callback(self):
>> """This method adds an on close callback that will be invoked by
>> pika
>> when RabbitMQ closes the connection to the publisher unexpectedly.
>>
>> """
>> LOGGER.info('Adding connection close callback')
>> self._connection.add_on_close_callback(self.on_connection_closed)
>>
>> def on_connection_closed(self, connection, reply_code, reply_text):
>> """This method is invoked by pika when the connection to RabbitMQ
>> is
>> closed unexpectedly. Since it is unexpected, we will reconnect to
>> RabbitMQ if it disconnects.
>>
>> :param pika.connection.Connection connection: The closed
>> connection obj
>> :param int reply_code: The server provided reply_code if given
>> :param str reply_text: The server provided reply_text if given
>>
>> """
>> self._channel = None
>> if self._closing:
>> self._connection.ioloop.stop()
>> else:
>> LOGGER.warning('Connection closed, reopening in 5 seconds:
>> (%s) %s',
>> reply_code, reply_text)
>> self._connection.add_timeout(5, self.reconnect)
>>
>> def on_connection_open(self, unused_connection):
>> """This method is called by pika once the connection to RabbitMQ
>> has
>> been established. It passes the handle to the connection object in
>> case we need it, but in this case, we'll just mark it unused.
>>
>> :type unused_connection: pika.SelectConnection
>>
>> """
>> LOGGER.info('Connection opened')
>> self.add_on_connection_close_callback()
>> self.open_channel()
>>
>> def reconnect(self):
>> """Will be invoked by the IOLoop timer if the connection is
>> closed. See the on_connection_closed method.
>>
>> """
>> # This is the old connection IOLoop instance, stop its ioloop
>> self._connection.ioloop.stop()
>>
>> if not self._closing:
>>
>> # Create a new connection
>> self._connection = self.connect()
>>
>> # There is now a new connection, needs a new ioloop to run
>> self._connection.ioloop.start()
>>
>> def add_on_channel_close_callback(self):
>> """This method tells pika to call the on_channel_closed method if
>> RabbitMQ unexpectedly closes the channel.
>>
>> """
>> LOGGER.info('Adding channel close callback')
>> self._channel.add_on_close_callback(self.on_channel_closed)
>>
>> def on_channel_closed(self, channel, reply_code, reply_text):
>> """Invoked by pika when RabbitMQ unexpectedly closes the channel.
>> Channels are usually closed if you attempt to do something that
>> violates the protocol, such as re-declare an exchange or queue
>> with
>> different parameters. In this case, we'll close the connection
>> to shutdown the object.
>>
>> :param pika.channel.Channel: The closed channel
>> :param int reply_code: The numeric reason the channel was closed
>> :param str reply_text: The text reason the channel was closed
>>
>> """
>> LOGGER.warning('Channel %i was closed: (%s) %s',
>> channel, reply_code, reply_text)
>> self._connection.close()
>>
>> def on_channel_open(self, channel):
>> """This method is invoked by pika when the channel has been
>> opened.
>> The channel object is passed in so we can make use of it.
>>
>> Since the channel is now open, we'll declare the exchange to use.
>>
>> :param pika.channel.Channel channel: The channel object
>>
>> """
>> LOGGER.info('Channel opened')
>> self._channel = channel
>> self.add_on_channel_close_callback()
>> self.setup_exchange(self.EXCHANGE)
>>
>> def setup_exchange(self, exchange_name):
>> """Setup the exchange on RabbitMQ by invoking the
>> Exchange.Declare RPC
>> command. When it is complete, the on_exchange_declareok method
>> will
>> be invoked by pika.
>>
>> :param str|unicode exchange_name: The name of the exchange to
>> declare
>>
>> """
>> LOGGER.info('Declaring exchange %s', exchange_name)
>> self._channel.exchange_declare(self.on_exchange_declareok,
>> exchange_name,
>> self.EXCHANGE_TYPE)
>>
>> def on_exchange_declareok(self, unused_frame):
>> """Invoked by pika when RabbitMQ has finished the
>> Exchange.Declare RPC
>> command.
>>
>> :param pika.Frame.Method unused_frame: Exchange.DeclareOk
>> response frame
>>
>> """
>> LOGGER.info('Exchange declared')
>> self.setup_queue(self.QUEUE)
>>
>> def setup_queue(self, queue_name):
>> """Setup the queue on RabbitMQ by invoking the Queue.Declare RPC
>> command. When it is complete, the on_queue_declareok method will
>> be invoked by pika.
>>
>> :param str|unicode queue_name: The name of the queue to declare.
>>
>> """
>> LOGGER.info('Declaring queue %s', queue_name)
>> self._channel.queue_declare(self.on_queue_declareok, queue_name)
>>
>> def on_queue_declareok(self, method_frame):
>> """Method invoked by pika when the Queue.Declare RPC call made in
>> setup_queue has completed. In this method we will bind the queue
>> and exchange together with the routing key by issuing the
>> Queue.Bind
>> RPC command. When this command is complete, the on_bindok method
>> will
>> be invoked by pika.
>>
>> :param pika.frame.Method method_frame: The Queue.DeclareOk frame
>>
>> """
>> LOGGER.info('Binding %s to %s with %s',
>> self.EXCHANGE, self.QUEUE, self.ROUTING_KEY)
>> self._channel.queue_bind(self.on_bindok, self.QUEUE,
>> self.EXCHANGE, self.ROUTING_KEY)
>>
>> def add_on_cancel_callback(self):
>> """Add a callback that will be invoked if RabbitMQ cancels the
>> consumer
>> for some reason. If RabbitMQ does cancel the consumer,
>> on_consumer_cancelled will be invoked by pika.
>>
>> """
>> LOGGER.info('Adding consumer cancellation callback')
>> self._channel.add_on_cancel_callback(self.on_consumer_cancelled)
>>
>> def on_consumer_cancelled(self, method_frame):
>> """Invoked by pika when RabbitMQ sends a Basic.Cancel for a
>> consumer
>> receiving messages.
>>
>> :param pika.frame.Method method_frame: The Basic.Cancel frame
>>
>> """
>> LOGGER.info('Consumer was cancelled remotely, shutting down: %r',
>> method_frame)
>> if self._channel:
>> self._channel.close()
>>
>> def acknowledge_message(self, delivery_tag):
>> """Acknowledge the message delivery from RabbitMQ by sending a
>> Basic.Ack RPC method for the delivery tag.
>>
>> :param int delivery_tag: The delivery tag from the Basic.Deliver
>> frame
>>
>> """
>> LOGGER.info('Acknowledging message %s', delivery_tag)
>> self._channel.basic_ack(delivery_tag)
>>
>> def on_message(self, unused_channel, basic_deliver, properties, body):
>> """Invoked by pika when a message is delivered from RabbitMQ. The
>> channel is passed for your convenience. The basic_deliver object
>> that
>> is passed in carries the exchange, routing key, delivery tag and
>> a redelivered flag for the message. The properties passed in is an
>> instance of BasicProperties with the message properties and the
>> body
>> is the message that was sent.
>>
>> :param pika.channel.Channel unused_channel: The channel object
>> :param pika.Spec.Basic.Deliver: basic_deliver method
>> :param pika.Spec.BasicProperties: properties
>> :param str|unicode body: The message body
>>
>> """
>> LOGGER.info('Received message # %s from %s: %s',
>> basic_deliver.delivery_tag, properties.app_id, body)
>> self.acknowledge_message(basic_deliver.delivery_tag)
>>
>> def on_cancelok(self, unused_frame):
>> """This method is invoked by pika when RabbitMQ acknowledges the
>> cancellation of a consumer. At this point we will close the
>> channel.
>> This will invoke the on_channel_closed method once the channel
>> has been
>> closed, which will in-turn close the connection.
>>
>> :param pika.frame.Method unused_frame: The Basic.CancelOk frame
>>
>> """
>> LOGGER.info('RabbitMQ acknowledged the cancellation of the
>> consumer')
>> self.close_channel()
>>
>> def stop_consuming(self):
>> """Tell RabbitMQ that you would like to stop consuming by sending
>> the
>> Basic.Cancel RPC command.
>>
>> """
>> if self._channel:
>> LOGGER.info('Sending a Basic.Cancel RPC command to RabbitMQ')
>> self._channel.basic_cancel(self.on_cancelok,
>> self._consumer_tag)
>>
>> def start_consuming(self):
>> """This method sets up the consumer by first calling
>> add_on_cancel_callback so that the object is notified if RabbitMQ
>> cancels the consumer. It then issues the Basic.Consume RPC command
>> which returns the consumer tag that is used to uniquely identify
>> the
>> consumer with RabbitMQ. We keep the value to use it when we want
>> to
>> cancel consuming. The on_message method is passed in as a
>> callback pika
>> will invoke when a message is fully received.
>>
>> """
>> LOGGER.info('Issuing consumer related RPC commands')
>> self.add_on_cancel_callback()
>> self._consumer_tag = self._channel.basic_consume(self.on_message,
>> self.QUEUE)
>>
>> def on_bindok(self, unused_frame):
>> """Invoked by pika when the Queue.Bind method has completed. At
>> this
>> point we will start consuming messages by calling start_consuming
>> which will invoke the needed RPC commands to start the process.
>>
>> :param pika.frame.Method unused_frame: The Queue.BindOk response
>> frame
>>
>> """
>> LOGGER.info('Queue bound')
>> self.start_consuming()
>>
>> def close_channel(self):
>> """Call to close the channel with RabbitMQ cleanly by issuing the
>> Channel.Close RPC command.
>>
>> """
>> LOGGER.info('Closing the channel')
>> self._channel.close()
>>
>> def open_channel(self):
>> """Open a new channel with RabbitMQ by issuing the Channel.Open
>> RPC
>> command. When RabbitMQ responds that the channel is open, the
>> on_channel_open callback will be invoked by pika.
>>
>> """
>> LOGGER.info('Creating a new channel')
>> self._connection.channel(on_open_callback=self.on_channel_open)
>>
>> def run(self):
>> """Run the example consumer by connecting to RabbitMQ and then
>> starting the IOLoop to block and allow the SelectConnection to
>> operate.
>>
>> """
>> self._connection = self.connect()
>> self._connection.ioloop.start()
>>
>> def stop(self):
>> """Cleanly shutdown the connection to RabbitMQ by stopping the
>> consumer
>> with RabbitMQ. When RabbitMQ confirms the cancellation,
>> on_cancelok
>> will be invoked by pika, which will then closing the channel and
>> connection. The IOLoop is started again because this method is
>> invoked
>> when CTRL-C is pressed raising a KeyboardInterrupt exception. This
>> exception stops the IOLoop which needs to be running for pika to
>> communicate with RabbitMQ. All of the commands issued prior to
>> starting
>> the IOLoop will be buffered but not processed.
>>
>> """
>> LOGGER.info('Stopping')
>> self._closing = True
>> self.stop_consuming()
>> self._connection.ioloop.start()
>> LOGGER.info('Stopped')
>>
>>
>> def main():
>> logging.basicConfig(level=logging.INFO, format=LOG_FORMAT)
>> example = ExampleConsumer('mqserver10', 5672, 'guest', 'guest')
>> try:
>> example.run()
>> except KeyboardInterrupt:
>> example.stop()
>>
>>
>> if __name__ == '__main__':
>> main()
>>
>>
>> On Thu, Aug 15, 2013 at 3:25 PM, Ask Solem <ask at rabbitmq.com> wrote:
>>
>>>
>>> On Aug 15, 2013, at 1:20 PM, Priyanki Vashi <vashi.priyanki at gmail.com>
>>> wrote:
>>>
>>> > Hi There ,
>>> >
>>> > 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.
>>> >
>>> > I was trying to use Tornado consumer example given on following pika
>>> site.
>>> >
>>> > https://pika.readthedocs.org/en/0.9.13/examples/tornado_consumer.html
>>> >
>>> > I am running into following error. The example is with URL connection
>>> method.
>>> > 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.
>>> >
>>> > I have pika 0.9.13 library installed. My consumer & Producer works
>>> fine with select.connection method so I believe library is correctly
>>> installed.
>>> >
>>> > Do I need to do something additional to get tornado connection working
>>> for both producer and consumer with pika?
>>> >
>>> > Please suggest.
>>> >
>>> > mq1 at mqserver1:~/Producer_Receiver/Latest$ python tornedo_c_1.py
>>> > Traceback (most recent call last):
>>> > File "tornedo_c_1.py", line 357, in <module>
>>> > main()
>>> > File "tornedo_c_1.py", line 351, in main
>>> > example.run()
>>> > File "tornedo_c_1.py", line 326, in run
>>> > self._connection = self.connect()
>>> > File "tornedo_c_1.py", line 59, in connect
>>> > adapters.TornadoConnection(self.parameters,
>>> self.on_connection_open, stop_ioloop_on_close=False)
>>> > TypeError: 'NoneType' object is not callable
>>>
>>>
>>> Maybe you passed None as a callback somewhere? What is the value of
>>> on_connection_open for example?
>>>
>>> _______________________________________________
>>> rabbitmq-discuss mailing list
>>> rabbitmq-discuss at lists.rabbitmq.com
>>> https://lists.rabbitmq.com/cgi-bin/mailman/listinfo/rabbitmq-discuss
>>>
>>
>>
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>>
>>
>
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