wso2esb - issue with proxying one-way operations - wso2

Question

As near as I can tell, the WSO2 ESB does not properly handle proxying a service operation that does not return a response message.
Here's the scenario:
We've got a code-first, axis2 generated web service sitting on WSO2 application server 4.1.0.
The java class that the service is based on has some methods like:
public void updateMyObject(MyObject obj) throws MyServiceException
Axis2 generates a WSDL that does not contain a response message, so this is essentially one-way.
NB: An axis2 generated client stub operating against this operation works fine. When invoking the stub in client code, the client blocks until the operation is successfully processed by the server. If an error occurs on the server, then the custom fault is raised and an exception is thrown on the client side.
But, we want to make this invocation via the ESB. Setting up a simple, basic proxy server will not work. When invoking the service via the ESB, the client code blocks indefinitely even though the remote service was successfully invoked.
I read somewhere that this can be fixed by adding the following to my inSequence:
<property action="set" name="OUT_ONLY" value="true"/>
<property action="set" name="FORCE_SC_ACCEPTED" scope="axis2" value="true"/>
This does the trick in the case that the remote service successfully processes the response. The client code no longer blocks.
However, if there is an error processing the request, the client doesn't know. The ESB basically "eats" the error.
This is no doubt because there is no call-back handler registered for the operation because of the OUT_ONLY setting. Search for OUT_ONLY in the link below for more info:
http://techfeast-hiranya.blogspot.ca/2009/12/wso2-esb-tips-tricks-03-transport.html
The FORCE_SC_ACCEPTED setting seems to be the thing that will keep the client from blocking on the success condition, presumably because that forces a 202 http response to the client so it stops waiting for a response.
Since the client operates as it should against the service for both success and error conditions but I am unable to configure a proxy service that yields the same behavior, in my opinion, the ESB is deficient in this way and that is a bug.
Of course, if there is a way I can configure it so that it does what I want, then I'd love to hear it.
But as near as I can tell, I think not registering a call-back is the wrong thing to do here, even if there is no response. I do not wish to implement a fire and forget here. Executions should still happen synchronously from the client side. My client is expecting an HTTP 200 response but with no body for success.
By examining the WSDL, the ESB should realize that the service has no response message but still register a call back. When the 200 OK is received on success, it should propagate this back to the client and unregister the call-back. When a Fault occurs, it should also relay that back to the client.
So, is there a way to accomplish what I want with the ESB or is it deficient in this way?

Answer 1

However, if there is an error processing the request, the client doesn't know. The ESB basically "eats" the error
What is happening to your client if you define a fault sequence for your proxy in this case?
If we register a call-back fro an outonly operation, what will happen is ESB will wait forever for the response and will run out of threads..
In oneway message;
If it is a successcase use these two properties;
<property action="set" name="OUT_ONLY" value="true"/>
<property action="set" name="FORCE_SC_ACCEPTED" scope="axis2" value="true"/>
For a failure case handle that in the fault sequence. I would like to know, what is happens in the fault scenario.