How to log the response message in a Registered Handler - ServiceStack RabbitMQ - servicestack

Question

Given this snippet of code:
//DirectApi
mqServer.RegisterHandler<LeadInformationInfo>(m =>
{
repository.SaveMessage(m as Message);
LeadInformationInfoResponse response = new LeadInformationInfoResponse();
try
{
var client = new JsonServiceClient(settingsFactory.GetMasterSetting("ProcessorApi:baseUri"));
response = client.Post(m.GetBody());
}
catch (WebServiceException webServiceException)
{
_log.Error("RegisterHandler<LeadInformationInfo>", webServiceException);
response = ((LeadInformationInfoResponse) webServiceException.ResponseDto);
response.CorrelationId = m.Id;
}
// Log response message here
return response;
}, 1);
I've gone to great lengths to make sure that a correlationId based off the original message Id property is propagated through the life of this message and any child messages spawned from this action. How do I get a handle on the response message so that I may log it in the handler? I only have access to the ResponseDto and not the message.
One of the reasons for this request is that the message queue client does not have access to the database, only the process that has the handler registered does. Hope that explains the situation better.
Just to clarify, this question is about persisting a MQ Response Message in the handler, the correlation Id is something that all messages in 1 request/response workflow will share. I'm also using ServiceStack ORMlite to persist the Message object, so querying this table by ID for troubleshooting is paramount.
Thank you,
Stephen

Answer 1

You're calling a WebService from within your MQ Handler:
var client = new JsonServiceClient(...);
response = client.Post(m.GetBody());
So there is no MQ Response which is only available in MQ Services. Although the WebService will return the response for the request that's sent so you can either use the CorrelationId on the MQ Request, otherwise you can have your Response DTO implement an interface like IHasCorrelationId and get it that way, e.g:
var correlationResponse = response as IHasCorrelationId;
if (correlationResponse != null)
{
var correlationId = correlationResponse.CorrelationId;
}
Create your own Instance of Message
As the Message<T> class is just a POCO if you wanted to create your own you can intialize your own instance:
var mqResponse = new Message<Response>(response);
If you only had the runtime late-bound type info, you can create one with:
var mqResponse = MessageFactory.Create(response);
Use RabbitMQ Message Filters
If you just wanted to log incoming and outgoing messages you can use the RabbitMQ Message Filters, e.g:
var mqServer = new RabbitMqServer("localhost")
{
PublishMessageFilter = (queueName, properties, msg) => {
properties.AppId = "app:{0}".Fmt(queueName);
},
GetMessageFilter = (queueName, basicMsg) => {
var props = basicMsg.BasicProperties;
receivedMsgType = props.Type; //automatically added by RabbitMqProducer
receivedMsgApp = props.AppId;
}
};