How to respond with status 500 (server error) when proxy fails? - wso2

Question

In our test environment we build a one-way proxy service that uses callout to get data from several other services. Now when one of those services fails wso2 proxy sends 202 accepted anyway. Is it possible to "catch exceptions" and return a different status?
I know that in this case it would be better to use a request-response proxy, but even if we would create a proxy that only stores the payload in a messagestore there could be issues regarding database where the payload would be stored (database is down, etc) and we don't want status 202 to be returned if the message was not stored in db.
edit:
Here is my proxy after changes suggested in first answer to my question:
<?xml version="1.0" encoding="UTF-8"?>
<proxy name="notifyOfClaimChangeOut" serviceGroup="" startOnLoad="true"
trace="disable" transports="http https" xmlns="http://ws.apache.org/ns/synapse">
<target>
<inSequence>
<property description="OUT_ONLY" name="OUT_ONLY" scope="default"
type="BOOLEAN" value="true"/>
<property name="FORCE_ERROR_ON_SOAP_FAULT" scope="default"
type="STRING" value="true"/>
<property description="OriginalPayload" expression="$body"
name="OriginalPayload" scope="default" type="STRING"/>
<iterate description=""
expression="$body//InsClaimData/PartnerList/PartnerEntry" id="" sequential="true">
<target>
<sequence>
<payloadFactory description="" media-type="xml">
<format>
<plat:FindCustomerSync xmlns:plat="http://platform.###.pl/">
<plat:request>
<plat:FirstName>$1</plat:FirstName>
<plat:LastName>$2</plat:LastName>
<plat:Pesel>$3</plat:Pesel>
</plat:request>
</plat:FindCustomerSync>
</format>
<args>
<arg evaluator="xml" expression="$body/PartnerEntry/BusinessPartner/personData/firstName"/>
<arg evaluator="xml" expression="$body/PartnerEntry/BusinessPartner/personData/lastName"/>
<arg evaluator="xml" expression="$body/PartnerEntry/BusinessPartner/personData/PESEL"/>
</args>
</payloadFactory>
<log level="custom">
<property expression="$body" name="property_name"/>
</log>
<callout action="http://platform.###.pl/FindCustomerSync"
description="QueryCustomersOut"
endpointKey="gov:###/endpoints/###/QueryCustomersOut.xml" initAxis2ClientOptions="false">
<source type="envelope"/>
<target key="QueryCustomersOutResponse"/>
</callout>
<log description="" level="custom" separator=",">
<property expression="$ctx:QueryCustomersOutResponse"
name="QueryCustomersOut"
xmlns:cla="http://###.###.io/service/internal/ClaimService" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"/>
</log>
</sequence>
</target>
</iterate>
<!--
<callout description="ClaimService"
endpointKey="gov:###/endpoints/###/ClaimService.xml" initAxis2ClientOptions="false">
<source type="envelope"/>
<target key="ClaimServiceResponse"/>
</callout>
<log description="ClaimService Response" level="custom">
<property expression="$ctx:ClaimServiceResponse" name="ClaimServiceResponse"/>
</log>
-->
<drop/>
</inSequence>
<outSequence/>
<faultSequence>
<property name="HTTP_SC" scope="axis2" type="STRING" value="500"/>
<log>
<property name="Error" value="Fault :("/>
</log>
</faultSequence>
</target>
<publishWSDL key="gov:###/schemas/###/ClaimService.wsdl"/>
</proxy>

Answer 1

You can use the HTTP_SC property to send status 500. You'll also need the makefault mediator to construct the fault message.
<property name="HTTP_SC" value="500" scope="axis2"/>
<makefault version="soap11">
You can refer this jira to get an idea.
In addition, in the inSequence, you may need to set FORCE_ERROR_ON_SOAP_FAULT property to move to the fault sequence when a soap fault occurs. Some explanation available here.
<inSequence>
<property name="FORCE_ERROR_ON_SOAP_FAULT" value="true" scope="default" type="STRING"/>
</inSequence>