pause stop consumer, get number of elements in queue

[rafareyeslopez]

Hello,

is there any way I can pause/resume a consumer?

Also can i get the number of current elements existing in a queue?

Thanks in advance.

[Gary Russell]

This forum is for the Spring AMQP project, so I assume you are using that.

To pause/resume, call stop()/start() on the SimpleMessageListenerContainer.

You can get queue depths via the UI if the Rabbit management plugin is installed. I don't know if there is a way to do it programmatically - ask the rabbit guys on their list: https://lists.rabbitmq.com/cgi-bin/m...bbitmq-discuss

[rafareyeslopez]

Thanks Gary,

I have already tryed that, the issue I think is that I have tried to do stop()/start() upon request via a request on a Controller, the code is the following:

@Controller
@RequestMapping("/consumer")
public class Consumer extends SimpleMessageListenerContainer {

public void handle(Map requestMap) {
log.info("Received message " );
log.info("Map: "+requestMap.toString());
}

@RequestMapping("/stop")
public void stop(){
super.stop();

}

@RequestMapping("/start")
public void start(){
superstart();

}

}


The configuration is:

<bean id="consumer" class="package.Consumer" >
<property name="connectionFactory" ref="connectionFactory" />
<property name="queueNames" value="queue" />
</bean>

<rabbit:connection-factory id="connectionFactory" />

<rabbit:template connection-factory="connectionFactory" />

<rabbit:admin connection-factory="connectionFactory"/>

<rabbit:queue durable="true" name="queue" />

<rabbit:listener-container connection-factory="connectionFactory" >
<rabbit:listener method="handle" ref="consumer" queues="queue" />
</rabbit:listener-container>


What should be the way to invoke methods to stop/start the consumer? Can't it be a request to a controller?

Thanks in advance.

This forum is for the Spring AMQP project, so I assume you are using that.

To pause/resume, call stop()/start() on the SimpleMessageListenerContainer.

You can get queue depths via the UI if the Rabbit management plugin is installed. I don't know if there is a way to do it programmatically - ask the rabbit guys on their list: https://lists.rabbitmq.com/cgi-bin/m...bbitmq-discuss

[Gary Russell]

Seems a little odd to me (making the container a controller rather than just injecting the container into the controller to keep the concerns separate). But, I don't see why it shouldn't work. What happens (in the log) when you invoke stop/start? Turn on DEBUG logging.

[rafareyeslopez]

I have tried that way too...

@Controller
@RequestMapping("/consumer")
public class ConsumerController {

@Autowired Consumer consumer;
/**
* Logger.
*/
private static Logger log = Logger.getLogger(ConsumerController.class);

@RequestMapping("/stop")
public void stop(){
try{
consumer.stop();
}catch(RuntimeException e){
log.info("Exception: "+e);
}
log.info("parado!");
}

@RequestMapping("/start")
public void start(){
try{
consumer.start();
}catch(Exception e){
log.info("Exception: "+e);
}
}
}



public class Consumer extends SimpleMessageListenerContainer {


/**
* Logger.
*/
private static Logger log = Logger
.getLogger(Consumer.class);

public void handle(Map requestMap) {
log.info("Received message " );
log.info("Map: "+requestMap.toString());
}

}

The error we get is:

(AbstractMessageListenerContainer.java:invokeError Handler:428) - Execution of Rabbit message listener failed, and no ErrorHandler has been set: class org.springframework.amqp.rabbit.listener.ListenerE xecutionFailedException: Failed to invoke target method 'handle' with argument type = [class org.apache.catalina.util.ParameterMap], value = [{{opmnc=[Ljava.lang.String;@b039b55}}]

non stop...

Seems a little odd to me (making the container a controller rather than just injecting the container into the controller to keep the concerns separate). But, I don't see why it shouldn't work. What happens (in the log) when you invoke stop/start? Turn on DEBUG logging.

[Gary Russell]

So the error is nothing to do with the inability to start/stop, it is something more basic.

It's not clear to me what you are trying to do. Why are you extending SimpleMessageListenerContainer? Why not just use the vanilla SMLC and give it a MessageListener (or MessageListenerAdapter)?