NService Bus Exception while Handling onStart when Assembly depends on Automapper - automapper

Question

We have an assembly using a refernce to the Automapper.dll. Starting the NServiceBus as Subscriber fails on Start with the following message:
Exception when starting endpoint, error has been logged. Reason: Could not load file or assembly 'file:///D:\Main\Src\Core\Core.MessageHandler\bin\Debug\AutoMapper.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)
StackTrace:
Server stack trace:
at Magnum.StateMachine.ExceptionActionDictionary`1.HandleException(T stateMachine, Event event, Object parameter, Exception exception)
at Magnum.StateMachine.EventActionList`1.Execute(T stateMachine, Event event, Object parameter)
at Magnum.StateMachine.EventActionBase`1.Execute(T instance, Event event, Object parameter)
at Magnum.StateMachine.State`1.RaiseEvent(T instance, BasicEvent`1 eevent, Object value)
at Magnum.StateMachine.StateMachine`1.RaiseEvent(Event raised)
at Topshelf.Internal.ServiceController`1.Start()
at Topshelf.Internal.IsolatedServiceControllerWrapper`1.Start()
at Topshelf.Internal.ServiceControllerProxy.Start()
at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext)
Exception rethrown at [0]:
at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
at Topshelf.Internal.ServiceControllerProxy.Start()
at Topshelf.Internal.FacadeToIsolatedServiceController`1.Start()
at Topshelf.Internal.ServiceCoordinator.Start()
at Topshelf.Internal.Hosts.ConsoleHost.Run()
at Topshelf.Internal.Actions.RunAsConsoleAction.Do(IRunConfiguration configuration)
at Topshelf.Runner.Host(IRunConfiguration configuration, String[] args)
at NServiceBus.Host.Program.Main(String[] args)
The file "Automapper.dll" exists! There is no problem in the Config. I checked this removing the dependency to the AutoMapper.dll and it works.
Here is the config:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<configSections>
<section name="MsmqTransportConfig"
type="NServiceBus.Config.MsmqTransportConfig, NServiceBus.Core" />
<section name="Logging" type="NServiceBus.Config.Logging, NServiceBus.Core" />
</configSections>
<MsmqTransportConfig
InputQueue="MyQueue#localhost"
NumberOfWorkerThreads="1"
MaxRetries="10"
ErrorQueue="ErrorQueue#localhost" />
<Logging Threshold="WARN" />
</configuration>
Any idea? Are there known problems with AutoMapper dependencies in NServiceBus?

Answer 1

In your endpoint configuration class (IConfigureThisEndpoint) it's common to implement IWantCustomInitialization as well. As part of that custom initialization you can specify the following:
public void Init()
{
Configure.With(AllAssemblies.Except("Automapper.dll"))
.AutofacBuilder()
.Log4Net(); // etc.
}
The "AllAssemblies.Except()" code instructs the NServiceBus configuration to completely ignore the Automapper assembly.
One other potential issue that may cause the issue is if you're using NServiceBus.Host.exe compiled against the CLR v2.0 (.NET v3.5) while Automapper is compiled against the CLR v4.0 (.NET 4.0). There are several builds of NServiceBus depending upon your CLR version. You may need to try running the CLR v4.0 version of change Automapper to be the .NET 3.5 version (which I believe isn't actively developed).

Answer 2

We had to use a binding redirect to get Autofac + NServiceBus to work. I believe the NServiceBus.ObjectBuilder.Autofac2.dll we referenced used an older version of Autofac than we were using.
app.config:
...
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="Autofac" publicKeyToken="17863af14b0044da" />
<bindingRedirect oldVersion="2.3.2.632" newVersion="2.4.3.700" />
</dependentAssembly>
</assemblyBinding>