Mule throttling on a backend service - activemq

Question

I have a back end service that I need to throttle access to. I'm trying to use the approach described here: http://blogs.mulesoft.org/synchronous-and-asynchronous-throttling-2/
I started with a simple pass through flow that receives a SOAP request and forwards it. When I hit this using the SOAPUI utility, I get the expected response in a second or two.
<http:connector name="httpConnector" doc:name="HTTP\HTTPS">
<receiver-threading-profile maxThreadsActive="1" maxBufferSize="100" />
</http:connector>
<jms:activemq-connector name="amqConnector" brokerURL="tcp://localhost:61616" specification="1.1" doc:name="AMQ" />
<flow name="Flow1" processingStrategy="synchronous" doc:name="Flow1">
<http:inbound-endpoint exchange-pattern="request-response"
host="localhost" port="8088" path="test" doc:name="HTTP"
mimeType="text/xml" encoding="UTF-8" connector-ref="httpConnector"/>
<http:outbound-endpoint
address="http://dnbdirect-api.dnb.com/DnBAPI-11"
exchange-pattern="request-response" doc:name="HTTP" mimeType="text/xml"/>
</flow>
If I then move the outbound call to a separate flow and add in the request-reply block, the behavior changes. I get no response back (nor do I get the "After queue" message from the logger) and SOAPUI eventually times out.
<http:connector name="httpConnector" doc:name="HTTP\HTTPS">
<receiver-threading-profile maxThreadsActive="1" maxBufferSize="100" />
</http:connector>
<jms:activemq-connector name="amqConnector" brokerURL="tcp://localhost:61616" specification="1.1" doc:name="AMQ" />
<flow name="Flow1" processingStrategy="synchronous" doc:name="Flow1">
<http:inbound-endpoint exchange-pattern="request-response"
host="localhost" port="8088" path="test" doc:name="HTTP"
mimeType="text/xml" encoding="UTF-8" connector-ref="httpConnector"/>
<message-properties-transformer doc:name="Message Properties">
<add-message-property key="AMQ_SCHEDULED_DELAY" value="5000"/>
</message-properties-transformer>
<logger message="Before queue" level="INFO"/>
<request-reply>
<jms:outbound-endpoint queue="request" connector-ref="amqConnector"></jms:outbound-endpoint>
<jms:inbound-endpoint queue="response" connector-ref="amqConnector"></jms:inbound-endpoint>
</request-reply>
<logger message="After queue" level="INFO"/>
</flow>
<flow name="flow2" doc:name="Flow2">
<jms:inbound-endpoint queue="request" connector-ref="amqConnector" doc:name="JMS"/>
<http:outbound-endpoint
address="http://dnbdirect-api.dnb.com/DnBAPI-11"
exchange-pattern="request-response" doc:name="HTTP" mimeType="text/xml" />
</flow>
The throttling behavior works as I see the delays if I pull out the call to the back end service. But I can't get it to work with the service call there.
What am I missing?

Answer 1

I found that the message's payload will be "ArrayList" after "request-reply".
so i add a java component to split it, then the result will be corrected.
#Override
public Object onCall(MuleEventContext eventContext) throws Exception {
MuleMessage message = eventContext.getMessage();
//int groupSize = message.getCorrelationGroupSize();
//System.out.println("############# correlationGroupSize: " + groupSize);
Object payload = message.getPayload();
if (payload != null && payload instanceof ArrayList) {
//message.setPayload(((ArrayList)payload).get(0));
return ((ArrayList)payload).get(0);
}
return message.getPayload();
}
the completed flow is:
<message-properties-transformer doc:name="Message Properties">
<add-message-property key="AMQ_SCHEDULED_DELAY" value="10000"/>
</message-properties-transformer>
<request-reply storePrefix="mainFlow">
<jms:outbound-endpoint queue="request" connector-ref="amqConnector" doc:name="JMS"></jms:outbound-endpoint>
<jms:inbound-endpoint queue="response" connector-ref="amqConnector" doc:name="JMS"></jms:inbound-endpoint>
</request-reply>
<component class="com.neusoft.fx.JmsMessageTransformer" doc:name="Java"/>
<message-properties-transformer doc:name="Set Content Type">
<delete-message-property key="Content-type" />
<add-message-property key="Content-Type" value="text/xml"/>
</message-properties-transformer>
<logger message="----- LOGGER ----- after #[groovy:message.toString()]" level="INFO" doc:name="Logger" />
</flow>

Answer 2

Try adding the following before the HTTP outbound endpoint in flow2:
<copy-properties propertyName="MULE_*"/>