Detect and identify consumer loss of connection

[Daniele Ivasse]

Hi guys,

I have to identify by IP address consumers that for some reason goes down. So I saw some people implementing a log queue listener to get close of connection messages. It worked for me.

After all, I had to build a cluster for RabbitMQ with mirrored queues and I chose to use HAProxy to handle load balancing between brokers in the cluster. Because of proxy, close of connection messages from log queue inform loss of connection between proxy's ip address instead of consumer one.

I was thinking to get port number of channel that is unique and it can identify each consumer. But the only way to consumer get this information is through message received. I don't think that this information is available on message...isn't it?

If you know any other way to handle with it, please let me know.

Thanks in advance,
Daniele

[Michael Klishin]

Channels are not identified by ports but by numbers. Consumers are not identified by channels but by consumer tags. You can retrieve this information via management API (which is a bit harder than it needs to be in 3.3, see list archives if you are not sure how list all consumers).

Note that consumer tags may be server-generated. Those will change if client loses connection and re-connects.

MK

[Daniele Ivasse]

Hi MK,

It's is possible to server gets this consumer tag information and sends to consumer? Because the point is, consumer has a unique identification for server and consumer knows which it is.

Daniele

[Michael Klishin]

In response to basic.consume and the with all consumer operations, most notably basic.deliver.

MK

[Daniele Ivasse]

I'm using spring-amqp and spring-rabbit packages. I implemented onMessage method of MessageListener to treat the message.

Can I get this information from message? Because there is no other place that I'm invoking some method to consume message.

Daniele

[Gary Russell]

Daniele, 

Spring AMQP doesn't currently expose the consumerTag to the listener.

Feel free to open up an 'Improvement' JIRA issue: https://jira.spring.io/browse/AMQP

Gary Russell

Spring AMQP Lead

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[Daniele Ivasse]

Thank you Gary.

There is another way to detect a consumer loss of connection instead of listening to log queue?

Daniele

[Gary Russell]

You could subclass the CachingConnectionFactory and override "shutdownCompleted()"; it is called by the rabbit client when channels are closed for any reason. You can examine the reason and reference properties of the ShutdownSignalException.

The default implementation in the CCF ignores "normal" channel closes and logs other reasons under ERROR.

[Laing, Michael]

You can also listen explicitly, I believe.

See 'rabbitmq_event_echange' here.

ml

[Laing, Michael]

That's 'rabbitmq_event_exchange'