In WSO2 ESB 4.7.0 can we do JMS rollback in receiving sequence?

Question

I have configured Apache ActiveMQ with transaction and CLIENT_ACKNOWLEDGE in WSO2 ESB 4.7.0. The axis2.xml config is :

<parameter name="transport.jms.SessionTransacted">true</parameter>
<parameter name="transport.jms.SessionAcknowledgement" locked="true">CLIENT_ACKNOWLEDGE</parameter>

I have a simple passthrough proxy with jms transport which passes the messages in the JMS queue to a jax-rs service. The proxy code is :

<?xml version="1.0" encoding="UTF-8"?>
<proxy xmlns="http://ws.apache.org/ns/synapse"
   name="MediaMoveQueue"
   transports="jms"
   startOnLoad="true"
   trace="enable">
<description/>
<target>
  <inSequence>
     <property name="messageType" value="application/json" scope="axis2"/>
     <property name="ContentType" value="application/json" scope="axis2"/>
     <send receive="JmsRollbackSequence">
        <endpoint>
           <address uri="http://192.168.1.2:9766/RestMediaMove_1.0.0/services/rest_media_move_i_f/restmediamoveif/hello"/>
        </endpoint>
     </send>

     <log level="custom">
        <property name="In MediaMoveQueue JMSERROR"
                  expression="get-property('JMSERROR')"/>
     </log>


     <switch source="get-property('JMSERROR')">
        <case regex="true">
           <property name="SET_ROLLBACK_ONLY" value="true" scope="axis2"/>
           <log level="custom">
              <property name="In MediaMoveQueue Transaction Action"
                        value="Rollbacked"/>
           </log>
        </case>
        <case regex="false">
           <log level="custom">
              <property name="In MediaMoveQueue Transaction Action"
                        value="Committed"/>                  
           </log>
         </case>
         <default>
           <property name="SET_ROLLBACK_ONLY" value="true" scope="axis2"/>
           <log level="custom">
              <property name="In MediaMoveQueue Transaction Action default"
                        value="Rollbacked"/>
           </log>
        </default>
     </switch>
  </inSequence>
  <outSequence>
     <log level="full">
        <property name="test" value="IN outsequence"/>
     </log>
     <send/>
  </outSequence>
</target>
<parameter name="transport.jms.ContentType">
  <rules>
     <jmsProperty>contentType</jmsProperty>
     <default>application/json</default>
  </rules>
</parameter>
</proxy>

The JmsRollbackSequence sequence receives the reply from the jax-rs service and depending on the reply success or failure returned, I would like to rollback the JMS transaction. But if I set the property in the JmsRollbackSequence it has absolutely no effect ( I tried it first before using the sequence shown below). The transaction is never rolled back. The rollback works only if the property is set in the inSequence. Here is the code for the JmsRollbackSequence :

<?xml version="1.0" encoding="UTF-8"?>
<sequence xmlns="http://ws.apache.org/ns/synapse" name="JmsRollbackSequence">
<property name="JMSERROR" value="true"/>
    <log level="full">
      <property name="test" value="IN JmsRollbackSequence"/>
     </log>

</sequence>

So I tried to set up a property called JMSERROR in the JmsRollbackSequence and by reading it after the send mediator in the inSequence I thought I can roll back the transaction in the inSequence. But this does not work either. The switch case in inSequence is called before the property is set up in JmsRollbackSequence so when I read it it always returns null.

So my questions are :

1) Can we set

<property name="SET_ROLLBACK_ONLY" value="true" scope="axis2"/>

in a sequence? Why does it not work in JmsRollbackSequence?

2) As mediators are supposed to be called sequentially, why does the switch case in inSequence run before the JmsRollbackSequence has a chance to read the reply and set up the JMSERROR property?

Kai Kai · Accepted Answer · 2013-12-16T09:45:33

I believe you can only control a transaction from within the same sequence or the fault sequence associated with it. But the WSO2 documentation doesn't really say anything about this...

Regarding your second question: The send mediator is non-blocking, i.e. the following mediators will be executed before the send mediator has returned. If you want it to wait for the response, then you need to use the callout mediator instead. Then you can evaluate the response and do the rollback if needed (all inside the inSequence).

In WSO2 ESB 4.7.0 can we do JMS rollback in receiving sequence?

1 Answers