"No message serializer has been configured" error when starting NServiceBus endpoint - nservicebus

Question

My GenericHost hosted service is failing to start with the following message:
2010-05-07 09:13:47,406 [1] FATAL NServiceBus.Host.Internal.GenericHost [(null)] <(null)> - System.InvalidOperationException: No message serializer has been con
figured.
at NServiceBus.Unicast.Transport.Msmq.MsmqTransport.CheckConfiguration() in d:\BuildAgent-02\work\672d81652eaca4e1\src\impl\unicast\NServiceBus.Unicast.Msmq\
MsmqTransport.cs:line 241
at NServiceBus.Unicast.Transport.Msmq.MsmqTransport.Start() in d:\BuildAgent-02\work\672d81652eaca4e1\src\impl\unicast\NServiceBus.Unicast.Msmq\MsmqTransport
.cs:line 211
at NServiceBus.Unicast.UnicastBus.NServiceBus.IStartableBus.Start(Action startupAction) in d:\BuildAgent-02\work\672d81652eaca4e1\src\unicast\NServiceBus.Uni
cast\UnicastBus.cs:line 694
at NServiceBus.Unicast.UnicastBus.NServiceBus.IStartableBus.Start() in d:\BuildAgent-02\work\672d81652eaca4e1\src\unicast\NServiceBus.Unicast\UnicastBus.cs:l
ine 665
at NServiceBus.Host.Internal.GenericHost.Start() in d:\BuildAgent-02\work\672d81652eaca4e1\src\host\NServiceBus.Host\Internal\GenericHost.cs:line 77
My endpoint configuration looks like:
public class ServiceEndpointConfiguration
: IConfigureThisEndpoint, AsA_Publisher, IWantCustomInitialization
{
public void Init()
{
// build out persistence infrastructure
var sessionFactory = Bootstrapper.InitializePersistence();
// configure NServiceBus infrastructure
var container = Bootstrapper.BuildDependencies(sessionFactory);
// set up logging
log4net.Config.XmlConfigurator.Configure();
Configure.With()
.Log4Net()
.UnityBuilder(container)
.XmlSerializer();
}
}
And my app.config looks like:
<configSections>
<section name="MsmqTransportConfig" type="NServiceBus.Config.MsmqTransportConfig, NServiceBus.Core" />
<section name="UnicastBusConfig" type="NServiceBus.Config.UnicastBusConfig, NServiceBus.Core" />
<section name="Logging" type="NServiceBus.Config.Logging, NServiceBus.Core" />
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" requirePermission="false" />
</configSections>
<Logging Threshold="DEBUG" />
<MsmqTransportConfig
InputQueue="NServiceBus.ServiceInput"
ErrorQueue="NServiceBus.Errors"
NumberOfWorkerThreads="1"
MaxRetries="2" />
<UnicastBusConfig
DistributorControlAddress=""
DistributorDataAddress=""
ForwardReceivedMessagesTo="NServiceBus.Auditing">
<MessageEndpointMappings>
<!-- publishers don't need to set this for their own message types -->
</MessageEndpointMappings>
</UnicastBusConfig>
<connectionStrings>
<add name="Db" connectionString="Data Source=..." providerName="System.Data.SqlClient" />
</connectionStrings>
<log4net debug="true">
<root>
<level value="INFO"/>
</root>
<logger name="NHibernate">
<level value="ERROR" />
</logger>
</log4net>
This has worked in the past, but seems to be failing when the generic host starts. My endpoint configuration is below, along with the app.config for the service. What is strange is that in my endpoint configuration, I am specifying to use the XmlSerializer for message serialization. I don't see any other errors in the console output preceding the error message. What am I missing?
Thanks, Steve

Answer 1

It looks like this was my own issue, though I had a hard time figuring that out based on the error message that I received. I have a base class for all of my messages:
public abstract class RequestMessage : IMessage {}
Recently, I created a partner message:
public abstract class ResponseMessage<TRequest>
where TRequest : RequestMessage {}
Apparently, when the host was starting up the IStartableBus, it would hit this generic message type and would not handle it correctly. I only really saw the underlying error when running with the DefaultBuilder, rather than the UnityBuilder that I am using in my project. It had something to do with the generic type constraint. I had assumed that this would work, but sadly it did not.
Regards,
Steve