Host throws assembly scanning errors preventing the endpoint from starting

[andreasohlund]

Symptoms

NServiceBus.Core: Could not load '{some assembly}'. Consider excluding that assembly from the scanning. System.Private.CoreLib: Assembly with same name is already loaded. is thrown at startup.

Who's affected

All customers using Version 4

Root cause

Since we run inside the azure functions host assemblies that we load and scan can be incompatible with versions referenced by the host.

Workaround

Manually exclude the problematic assemblies using:

public override void Configure(IFunctionsHostBuilder functionsHostBuilder)
{
    functionsHostBuilder.UseNServiceBus(endpointConfiguration =>
    {
        endpointConfiguration.AdvancedConfiguration.AssemblyScanner()
                .ExcludeAssemblies("some assembly");
    });
}

[andreasohlund]

@SzymonPobiega @WojcikMike ready for final review

[seanfarmar]

This workaround worked for us