Executing FaultSequence for SOAPFaults in WSO2ESB

In WSO2ESB/Synapse, whenever mediation errors occur, user can execute faultsequence to find error details.
The fault sequence can be defined at a sequence level or at proxy service level. Mediation level issues and endpoint errors can be captured at faultsequence. But SOAPFault can not be captured at fault sequence, since ESB/Synapse will treat it as the response from the endpoint.
But from user's pont of view , those are service endpoint failures which need to be handled properly.
To handle the soapfaults, now we can use a property which forces to execute fault sequence whenever soapfault occurs.
We need to set  following property before sending the message to endpoint.;

<property name="FORCE_ERROR_ON_SOAP_FAULT" value="true"/>

Sample conf;

<proxy xmlns="http://ws.apache.org/ns/synapse"
       name="testProxy"
       transports="https,http"
       statistics="disable"
       trace="disable"
       startOnLoad="true">
  <target faultSequence="myfaultSeq">
      <inSequence>
         <property name="FORCE_ERROR_ON_SOAP_FAULT" value="true"/>
      </inSequence>
      <outSequence>
         <send/>
      </outSequence>
      <endpoint>
         <address uri="http://localhost:9764/services/echo/"/>
     </endpoint>
   </target>
   <description/>
</proxy>
           

In the above sample , whenever we get soapfault, the 'myfaultSeq' will be executed.

Related Post: Sending mails for errors

Class Endpoints:Sample

In my older post , I mentioned that Class endpoint(ie: custom endpoints) feature is available in later versions of synapse, which is branched in WSO2 svn location.
Since, there are number of usecases to implement the class endpoint, i thought to write a simple sample using class endpoints.

Sample
All message sending logic is handled in the Axis2MEPClient.java class in synapse core. For instance, if we want to have our custom client which to do its own message sending  logic,we could write this type of endpoints.

In the following sample, i have defined an Custom Class Endpoint(ie:UAddressEndpoint) which extends the Synapse.AbstarctEndpoint class to define its own endpoint logic.

I read a parameter (this parameter ,we provide from endpoint configuration) from registry , where i saved my custom endpoint configuration . From that endpoint configuration i read  all endpoint related parameters, and use that as an Endpoint and have a separate   logic to send out message,

package org.wso2.carbon.endpoint.uep;

import org.apache.axis2.AxisFault;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.synapse.MessageContext;
import org.apache.synapse.endpoints.AbstractEndpoint;
import org.wso2.carbon.endpoint.uep.util.UEndpointUtil;
import org.wso2.carbon.unifiedendpoint.core.UnifiedEndpoint;

/**
 * ESB specific UAddressEndpoint class,extended from synapse Abstractendpoint.
 * 
 */
public class UAddressEndpoint extends AbstractEndpoint {

/**
* The registry location of the uep configuration,where it is stored
* Eg:conf:/repositoryuepTestEP.xml
*/
private String uepConfigurationPath;

private static final Log log = LogFactory.getLog(UAddressEndpoint.class);

public UAddressEndpoint() {

}

/**
* Getter and Setter of the parameter which we define at the classendpoint
* configuration.
* eg:
* name="uepConfigurationPath">conf:/repositoryuepTestEP.xml

* 
         * @param uepConfiguration
*/
public void setUepConfigurationPath(String uepConfigurationPath) {
this.uepConfigurationPath = uepConfigurationPath;
}

public String getUepConfigurationPath() {
return uepConfigurationPath;

}

/**
* Override the AbstractEndpoint.send(). Use the UEP handler to
* get endpoint specific
* Configurations
* 
*/
public void send(MessageContext synMessageContext) {
if (log.isDebugEnabled()) {
log.debug("Executing UAddressEndpoint Sender ");
}

try {
UAddressEndpointDefinition addressEPDefinition = new UAddressEndpointDefinition();
UEndpointUtil uepUtil = new UEndpointUtil();

UnifiedEndpoint unifiedEndpoint = uepUtil.getUnifiedEndpoint(uepConfigurationPath);
addressEPDefinition.setEndpointDefinition(unifiedEndpoint);
UEndpointAxis2MEPClient.send(unifiedEndpoint, getDefinition(), synMessageContext);
} catch (AxisFault e) {
log.error("Error in executing the message", e);
}
}

}

In the above sample,if you notice that I have my own class(ie: UEndpointAxis2MEPClient) to handle the message sending logic.

If we want to use this type of class endpoint, in synapse configuration we have to define our custom endpoint like this;

<endpoint name="CustomEndpoint">
                    <class name="org.wso2.carbon.endpoint.uep.UAddressEndpoin">
                                 <parameter name="uepConfigurationPath">conf:/repositoryuepTestEP.xml</parameter>
                    </class>
</endpoint>

Class Endpoints in Synapse

In Apache synapse, there are predefined endpoints , which can be used as service endpoints to send out the message from the mediation engine. Currently available endpoints are;

• Address Endpoint
• Default Endpoint 
• WSDL endpoint
• Load balance Endpoint 
• Failover Endpoint 
• Dynamic Load balance Endpoint

Anyway, Synapse does not support to extend the endpoint capability to add a custom endpoint according to the user needs as in mediators.(ie: class mediator)
To have such a feature, same like class mediator functionality, class endpoint concept has been implemented. The patch has been provided to the synapse project.

To add a class endpoint in the mediation flow, user should add following configuration;

<endpoint name="CustomEndpoint">
                    <class name="org.apache.synapse.endpoint.CustomEndpoint">
                                 <parameter name="foo">XYZ</parameter>*
                    </class>
</endpoint>

The "CustomEndpoint" class implementation should be the child class of the AbstractEndpoint class. Using this type of class endpoints, user can add his own message sending logic or can load a custom synapse environment for a particular endpoint.

Related post: http://vvratha.blogspot.com/2013/06/class-endpointssample.html