Sample 651: Using Synapse Observers

Objective: Demonstrate the ability to monitor the Synapse configuration at runtime using the SynapseObserver interface

Open the synapse.properties file in the ESB_HOME/webapps/ROOT/WEB-INF/classes directory using a text editor and add the following line to the synapse.properties file. This entry defines the simple logging Synapse observer.

synapse.observers=samples.userguide.SimpleLoggingObserver

Open the log4j.properties file in the ESB_HOME/lib directory and add the followin line which sets the INFO log level to the samples.userguide package.

log4j.category.samples.userguide=INFO

Start Synapse using any of the sample configurations. The SimpleLoggingObserver will capture events that occur while constructing the Synapse configuration and log them on the console as follows.

  2009-08-06 14:30:24,578 [-] [main]  INFO SimpleLoggingObserver Simple logging observer initialized...Capturing Synapse events...
  2009-08-06 14:30:24,604 [-] [main]  INFO SimpleLoggingObserver Endpoint : a3 was added to the Synapse configuration successfully
  2009-08-06 14:30:24,605 [-] [main]  INFO SimpleLoggingObserver Endpoint : a2 was added to the Synapse configuration successfully
  2009-08-06 14:30:24,606 [-] [main]  INFO SimpleLoggingObserver Endpoint : null was added to the Synapse configuration successfully
  2009-08-06 14:30:24,611 [-] [main]  INFO SimpleLoggingObserver Local entry : a1 was added to the Synapse configuration successfully
  2009-08-06 14:30:24,649 [-] [main]  INFO SimpleLoggingObserver Proxy service : StockQuoteProxy2 was added to the Synapse configuration successfully
  2009-08-06 14:30:24,661 [-] [main]  INFO SimpleLoggingObserver Proxy service : StockQuoteProxy1 was added to the Synapse configuration successfully
  2009-08-06 14:30:24,664 [-] [main]  INFO SimpleLoggingObserver Sequence : main was added to the Synapse configuration successfully
  2009-08-06 14:30:24,701 [-] [main]  INFO SimpleLoggingObserver Sequence : fault was added to the Synapse configuration successfully

The SimpleLoggingObserver is implemented as follows. It does not override any of the event handler implementations in the AbstractSynapseObserver class. The AbstractSynapseObserver logs all the received events by default.

 package samples.userguide;

 import org.apache.synapse.config.AbstractSynapseObserver;

 public class SimpleLoggingObserver extends AbstractSynapseObserver {

     public SimpleLoggingObserver() {
         super();
         log.info("Simple logging observer initialized...Capturing Synapse events...");
     }
 }