NService bus and the GAC

Question

Hi there,

I have recently tried to migrate the NServiceBus libraries to the GAC as they are pretty big and are required in nearly all of my software. I am using the newest .NET 4.0 Build (2.0.0.1219) and have used GACUTIL to copy NServiceBus & NServiceBus.Core into the new GAC and log4net into the old 2.0 GAC. I have managed to get log4net working by wiring in the version and PublicKeyToken but I cannot get the NServiceBus.Core working. Every time I start a piece of software I get the following error:

"Type NServiceBus.Unicast.Transport.CompletionMessage was not registered in the serializer. Check that it appears in the list of configured assemblies/types to scan."

When I copy the DLL NServiceBus.Core to the local folder it works fine.

my config looks like this:

<configSections>
<section name="MsmqTransportConfig" type="NServiceBus.Config.MsmqTransportConfig, NServiceBus.Core, Version=2.0.0.1219, Culture=neutral, PublicKeyToken=9fc386479f8a226c" />
<section name="UnicastBusConfig" type="NServiceBus.Config.UnicastBusConfig, NServiceBus.Core, Version=2.0.0.1219, Culture=neutral, PublicKeyToken=9fc386479f8a226c" />
<section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=1b44e1d426115821" />
<sectionGroup name="common">
  <section name="logging" type="Common.Logging.ConfigurationSectionHandler, NServiceBus.Core, Version=2.0.0.1219, Culture=neutral, PublicKeyToken=9fc386479f8a226c"/>
</sectionGroup>

So i'm wondering has anyone else got NServiceBus successfully working with the GAC?

Cheers

Answer 1

NServiceBus scans the assemblies in a directory (the run directory for an application, the website's compiled directory for a web application) in order to load all the message handlers, and that means it needs to scan itself as well for all the types it needs for dependency injection.

I'm not sure that this model supports assemblies living in the GAC by default, although if you're configuring NServiceBus yourself, you can specify the assemblies to load yourself through the NServiceBus.Configure.With(params Assembly[] assemblies) overload, just make sure to include all the NServiceBus assemblies and Log4Net at the very least.

However, I would contend that GAC-ing the NSB assemblies might not be the best idea. Each endpoint having its own copy of the assembly reinforces the autonomy of the endpoints, and will make it much easier if you ever need to upgrade to a new version of NServiceBus, since you would be able to test each endpoint individually and not just put a new assembly in the GAC, add a binding redirect, and hope everything continues to run fine.