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Posted to users@servicemix.apache.org by Tropi Geek <tr...@gmail.com> on 2008/02/29 23:27:15 UTC

Exception Listener in servicemix

Guys, things seem to be working very well with servicemix but one of the
challenges I am facing is to track errors happening at component level.

Is there a generic listener that I can use/implement to listen to all
exceptions and then send it to a common exception queue component. I need to
report issues back to the requesting application. I can do that with most
bean/pojo components in a  try/catch block but not with any components.

Seems like a generic problem but I dont seem to be getting the right pointer
for this. Kindly help.

-- tg

Re: Exception Listener in servicemix

Posted by Bruce Snyder <br...@gmail.com>.

On Sat, Mar 1, 2008 at 12:51 PM, Guillaume Nodet <gn...@gmail.com> wrote:
> Maybe we should put this example on a wiki page ?

Yeah I was thinking that as well. Let me enhance it a bit and I'll
commit it and document it on the wiki.

Bruce
-- 
perl -e 'print unpack("u30","D0G)U8V4\@4VYY9&5R\"F)R=6-E+G-N>61E<D\!G;6%I;\"YC;VT*"
);'

Apache ActiveMQ - http://activemq.org/
Apache Camel - http://activemq.org/camel/
Apache ServiceMix - http://servicemix.org/
Apache Geronimo - http://geronimo.apache.org/

Blog: http://bruceblog.org/

Re: Exception Listener in servicemix

Posted by Guillaume Nodet <gn...@gmail.com>.

Maybe we should put this example on a wiki page ?

On Sat, Mar 1, 2008 at 4:55 PM, Bruce Snyder <br...@gmail.com> wrote:
>
> On Fri, Feb 29, 2008 at 3:27 PM, Tropi Geek <tr...@gmail.com> wrote:
>  > Guys, things seem to be working very well with servicemix but one of the
>  >  challenges I am facing is to track errors happening at component level.
>  >
>  >  Is there a generic listener that I can use/implement to listen to all
>  >  exceptions and then send it to a common exception queue component. I need to
>  >  report issues back to the requesting application. I can do that with most
>  >  bean/pojo components in a  try/catch block but not with any components.
>  >
>  >  Seems like a generic problem but I dont seem to be getting the right pointer
>  >  for this. Kindly help.
>
>  Well, you could create an ExchangeListener to capture every message
>  exchange flowing through the NMR. This gives you the ability to
>  manipulate the message exchanges however you like including checking
>  for errors on the exchange. Below is an example of something I wrote
>  to enhance the error messages on an exchange:
>
>  package org.apache.servicemix.jbi.exceptions;
>
>  import javax.jbi.messaging.MessageExchange;
>
>  import org.apache.servicemix.jbi.event.ExchangeEvent;
>  import org.apache.servicemix.jbi.event.ExchangeListener;
>
>  /**
>   * An {@link org.apache.servicemix.jbi.event.ExchangeListener} implementation
>   * to handle exception customization.
>   *
>   * @org.apache.xbean.XBean element="exceptionListenerService"
>   * @version $Revision$
>   * @author bsnyder
>   */
>  public class ExceptionListenerService implements ExchangeListener {
>
>     public void exchangeAccepted(ExchangeEvent event) {
>         // TODO Auto-generated method stub
>
>     }
>
>     public void exchangeSent(ExchangeEvent event) {
>         MessageExchange me = event.getExchange();
>         Exception exception = null;
>
>         if (me.getError() != null) {
>             exception = analyzeException(me);
>         }
>
>         me.setError(exception);
>     }
>
>     /**
>      * This method abstracts any special exception handling behavior.
>      *
>      * @TODO Abstract this further using pluggable strategies to hold the
>      * custom functionality. Then we just stuff the strategies that are
>      * named in the servicemix.xml config into an array and just walk the
>      * array, invoking the execute method on each strategy.
>      *
>      * @param error The exception that was thrown
>      * @param endpointName The name of the endpoint that threw the exception
>      * @return
>      */
>     private Exception analyzeException(MessageExchange me) {
>         Exception error = me.getError();
>         String serviceName = me.getEndpoint().getServiceName().toString();
>         String endpointName = me.getEndpoint().getEndpointName();
>         String errorMessage = error.getMessage();
>
>         // Add calls to custom processing here
>
>         StringBuilder newErrorMessage =
>             new StringBuilder("The following error was caused by service: [");
>         newErrorMessage.append(serviceName != null ? serviceName : "null");
>         newErrorMessage.append("] and endpoint: [");
>         newErrorMessage.append(endpointName != null ? endpointName : "null");
>         newErrorMessage.append("] ");
>         newErrorMessage.append("Original error: ");
>         newErrorMessage.append(errorMessage);
>
>         return new Exception(newErrorMessage.toString(), error);
>     }
>
>  }
>
>  To use this with ServiceMIx, you simply register it as a service in
>  the servicemix.xml file using the XBean element in the class level
>  XBean annotation (exceptionListenerService).
>
>  Bruce
>  --
>  perl -e 'print unpack("u30","D0G)U8V4\@4VYY9&5R\"F)R=6-E+G-N>61E<D\!G;6%I;\"YC;VT*"
>  );'
>
>  Apache ActiveMQ - http://activemq.org/
>  Apache Camel - http://activemq.org/camel/
>  Apache ServiceMix - http://servicemix.org/
>  Apache Geronimo - http://geronimo.apache.org/
>
>  Blog: http://bruceblog.org/
>



-- 
Cheers,
Guillaume Nodet
------------------------
Blog: http://gnodet.blogspot.com/

Re: Exception Listener in servicemix

Posted by Guillaume Nodet <gn...@gmail.com>.

What is the relationship between your camel route and the exception listener ?
If the example does not work anymore, this certainly means that the
listener does
something not compliant.  FYI, listeners can read or modify the
exchange, but can not
route it somewhere else, though it should be possible to do that by
sending a new
exchange to another component.

On Thu, May 22, 2008 at 7:27 AM, pratibhaG <pr...@in2m.com> wrote:
>
> I included the listener like this
> <sm:services>
>      <sm:statistics statsInterval="10" dumpStats="true" />
> </sm:services>
> <sm:listeners>
>        <bean id="errorBean" class="errorhandling.ExceptionListenerService"
> />
> </sm:listeners>
>
> and I tried this example:
> example: take a message from queue tutorial.camel.queue13 and pass it to a
> bean. The bean sets the message status to error. As the status is error the
> message is put in queue tutorial.camel.queue1
> here are some of the files of the example:
> jms-su xbean.xml
> <beans xmlns:jms="http://servicemix.apache.org/jms/1.0"
>       xmlns:esb="http://esbinaction.com/errorhandling">
>
>  <jms:endpoint service="esb:errorHandlerDSL"
>       endpoint="errorEndpoint"
>       role="consumer"
>       destinationStyle="queue"
>       jmsProviderDestinationName="tutorial.camel.queue13"
>       defaultMep="http://www.w3.org/2004/08/wsdl/in-only"
>       connectionFactory="#connectionFactory"/>
>
>  <jms:endpoint service="esb:errorStorageService"
>       endpoint="errorStorageEndpoint"
>       role="provider"
>       destinationStyle="queue"
>       jmsProviderDestinationName="tutorial.camel.queue1"
>       defaultMep="http://www.w3.org/2004/08/wsdl/in-only"
>       connectionFactory="#connectionFactory"/>
>
>  <bean id="connectionFactory"
> class="org.apache.activemq.ActiveMQConnectionFactory">
>    <property name="brokerURL" value="tcp://localhost:61616" />
>  </bean>
>
> </beans>
>
> camel route builder java file
> package errorhandling.camel;
>
> import org.apache.camel.builder.RouteBuilder;
>
> public class CamelErrorHandler extends RouteBuilder {
>
>        private final static String NAMESPACE =
> "http://esbinaction.com/errorhandling";
>        private final static String SERVICE_IN = "jbi:service:" +
>                NAMESPACE + "/errorHandlerDSL";
>        private final static String BEAN_IN = "jbi:service:" +
>                NAMESPACE + "/errorComponent";
>        private final static String ERROR_IN = "jbi:service:" +
>                NAMESPACE + "/errorStorageService";
>
>        public void configure() {
>
> /*errorHandler(deadLetterChannel(ERROR_IN).maximumRedeliveries(2));
>           from(SERVICE_IN).to(BEAN_IN);*/
>
> from(SERVICE_IN).errorHandler(deadLetterChannel(ERROR_IN).maximumRedeliveries(1)).to(BEAN_IN);
>            //from(SERVICE_IN).errorHandler(noErrorHandler).to(BEAN_IN);
>        }
> }
>
>
> Now if I don't put
> <sm:listeners>
>        <bean id="errorBean" class="errorhandling.ExceptionListenerService"
> />
> </sm:listeners>
>
> in conf/servicemix.xml then the example works fine. That is the message is
> consumed from tutorial.camel.queue13 and is routed to tutorial.camel.queue1
> as i am setting message status to error in my bean.
>
> But if I put
> <sm:listeners>
>        <bean id="errorBean" class="errorhandling.ExceptionListenerService"
> />
> </sm:listeners>
>
> in conf/servicemix.xml then the example does not work as expected.  That is
> the message is consumed from tutorial.camel.queue13 but not routed to
> tutorial.camel.queue1 even when  i am setting message status to error in my
> bean.
>
> Is it the same way the listener is supposed to behave or am I missing
> something.
>
> Another thing is that I never saw the message "The following error was
> caused by service"  which is created in my listener. Where this message will
> be shown?
>
> -Pratibha
>
>
>
> --
> View this message in context: http://www.nabble.com/Exception-Listener-in-servicemix-tp15769242p17397607.html
> Sent from the ServiceMix - User mailing list archive at Nabble.com.
>
>



-- 
Cheers,
Guillaume Nodet
------------------------
Blog: http://gnodet.blogspot.com/