Blazor client side app does not build when project has nlog dependency

Question

I am new to Blazor and I want to make use of a library that has NLog 4.6.2 as a dependency. I am not trying to log using NLog, just trying to make use of that library. In order to isolate the issue I added NLog 4.6.2 as dependency in the .csproj file

<PackageReference Include="NLog" Version="4.6.2" />

When i build the application i get the following error:

Severity    Code    Description Project File    Line    Suppression State
Error   MSB3073 The command "dotnet "C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.blazor.mono\0.10.0-preview6.19303.4\build\netstandard1.0\../../tools/illink/illink.dll" -l none --disable-opt unreachablebodies --verbose --strip-security true --exclude-feature com --exclude-feature sre -v false -c link -u link -b true -d "C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.blazor.mono\0.10.0-preview6.19303.4\build\netstandard1.0\../../tools/mono/bcl/" -d "C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.blazor.mono\0.10.0-preview6.19303.4\build\netstandard1.0\../../tools/mono/bcl/Facades/" -o "C:\Users\sgerene\Documents\15-Source-Code\CDP4\CDP4-Blazor\CDP4WebApp\obj\Debug\netstandard2.0\blazor\linker/" -x "C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.blazor.build\3.0.0-preview6.19307.2\targets\BuiltInBclLinkerDescriptor.xml" -x "C:\Users\sgerene\Documents\15-Source-Code\CDP4\CDP4-Blazor\CDP4WebApp\obj\Debug\netstandard2.0\blazor\linker.descriptor.xml" -a "C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.authorization\3.0.0-preview6.19307.2\lib\netstandard2.0\Microsoft.AspNetCore.Authorization.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.blazor\3.0.0-preview6.19307.2\lib\netstandard2.0\Microsoft.AspNetCore.Blazor.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.components\3.0.0-preview6.19307.2\lib\netstandard2.0\Microsoft.AspNetCore.Components.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.components.browser\3.0.0-preview6.19307.2\lib\netstandard2.0\Microsoft.AspNetCore.Components.Browser.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.aspnetcore.hosting.abstractions\2.1.1\lib\netstandard2.0\Microsoft.AspNetCore.Hosting.Abstractions.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.aspnetcore.hosting.server.abstractions\2.1.1\lib\netstandard2.0\Microsoft.AspNetCore.Hosting.Server.Abstractions.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.aspnetcore.http\2.1.1\lib\netstandard2.0\Microsoft.AspNetCore.Http.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.aspnetcore.http.abstractions\2.1.1\lib\netstandard2.0\Microsoft.AspNetCore.Http.Abstractions.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.aspnetcore.http.features\2.1.1\lib\netstandard2.0\Microsoft.AspNetCore.Http.Features.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.metadata\3.0.0-preview6.19307.2\lib\netstandard2.0\Microsoft.AspNetCore.Metadata.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.aspnetcore.routing.abstractions\2.1.1\lib\netstandard2.0\Microsoft.AspNetCore.Routing.Abstractions.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.aspnetcore.webutilities\2.1.1\lib\netstandard2.0\Microsoft.AspNetCore.WebUtilities.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.extensions.configuration\2.1.0\lib\netstandard2.0\Microsoft.Extensions.Configuration.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.extensions.configuration.abstractions\2.1.1\lib\netstandard2.0\Microsoft.Extensions.Configuration.Abstractions.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.extensions.configuration.binder\2.1.0\lib\netstandard2.0\Microsoft.Extensions.Configuration.Binder.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.extensions.dependencyinjection\3.0.0-preview6.19304.6\lib\netstandard2.0\Microsoft.Extensions.DependencyInjection.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.extensions.dependencyinjection.abstractions\3.0.0-preview6.19304.6\lib\netstandard2.0\Microsoft.Extensions.DependencyInjection.Abstractions.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.extensions.fileproviders.abstractions\2.1.1\lib\netstandard2.0\Microsoft.Extensions.FileProviders.Abstractions.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.extensions.hosting.abstractions\2.1.1\lib\netstandard2.0\Microsoft.Extensions.Hosting.Abstractions.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.extensions.logging\2.1.0\lib\netstandard2.0\Microsoft.Extensions.Logging.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.extensions.logging.abstractions\3.0.0-preview6.19304.6\lib\netstandard2.0\Microsoft.Extensions.Logging.Abstractions.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.extensions.objectpool\2.1.1\lib\netstandard2.0\Microsoft.Extensions.ObjectPool.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.extensions.options\3.0.0-preview6.19304.6\lib\netstandard2.0\Microsoft.Extensions.Options.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.extensions.primitives\3.0.0-preview6.19304.6\lib\netstandard2.0\Microsoft.Extensions.Primitives.dll" -a "C:\Users\sgerene\.nuget\packages\microsoft.jsinterop\3.0.0-preview6.19304.6\lib\netstandard2.0\Microsoft.JSInterop.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.net.http.headers\2.1.1\lib\netstandard2.0\Microsoft.Net.Http.Headers.dll" -a "C:\Users\sgerene\.nuget\packages\mono.webassembly.interop\3.0.0-preview6.19304.6\lib\netstandard2.0\Mono.WebAssembly.Interop.dll" -a "C:\Users\sgerene\.nuget\packages\nlog\4.6.4\lib\netstandard2.0\NLog.dll" -a "C:\Users\sgerene\.nuget\packages\nlog.extensions.logging\1.5.1\lib\netstandard2.0\NLog.Extensions.Logging.dll" -a "C:\Users\sgerene\.nuget\packages\nlog.web.aspnetcore\4.8.4\lib\netstandard2.0\NLog.Web.AspNetCore.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\system.buffers\4.5.0\lib\netstandard2.0\System.Buffers.dll" -a "C:\Users\sgerene\.nuget\packages\system.componentmodel.annotations\4.6.0-preview6.19303.8\lib\netstandard2.0\System.ComponentModel.Annotations.dll" -a "C:\Users\sgerene\.nuget\packages\system.memory\4.5.3\lib\netstandard2.0\System.Memory.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\system.numerics.vectors\4.5.0\lib\netstandard2.0\System.Numerics.Vectors.dll" -a "C:\Users\sgerene\.nuget\packages\system.runtime.compilerservices.unsafe\4.6.0-preview6.19303.8\lib\netstandard2.0\System.Runtime.CompilerServices.Unsafe.dll" -a "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\system.text.encodings.web\4.5.0\lib\netstandard2.0\System.Text.Encodings.Web.dll" -a "C:\Users\sgerene\.nuget\packages\system.text.json\4.6.0-preview6.19303.8\lib\netstandard2.0\System.Text.Json.dll" -a "C:\Users\sgerene\.nuget\packages\system.threading.tasks.extensions\4.5.2\lib\netstandard2.0\System.Threading.Tasks.Extensions.dll" -a "C:\Users\sgerene\Documents\15-Source-Code\CDP4\CDP4-Blazor\CDP4WebApp\obj\Debug\netstandard2.0\CDP4WebApp.dll"" exited with code -532462766.    CDP4WebApp  C:\Users\sgerene\.nuget\packages\microsoft.aspnetcore.blazor.build\3.0.0-preview6.19307.2\targets\Blazor.MonoRuntime.targets    439 

Can someone point me in the right direction to help me get this to work. All i am trying to achieve is that the NLog dependency allows me to build and run the app... not trying to log for now.

Answer 1

If you inspect the output you can see that this fails because NLog depends on System.Threading.Thread.CurrentPrincipal.

Blazor/Mono doesn't support threads (so it would have thrown NotImplemented anyway) but Mono.Wasm is also severely pruned, so you now get this Linker error.

I want to make use of a library that has NLog 4.6.2 as a dependency.

That is unfortunate. The wise lesson here is that libraries shouldn't have such strong dependencies. But that won't help you here.

The only realistic solution I can see is to use Blazor server-side. Or change or replace that library.

When the libraries are yours to change, make them depend on a logging interface. This is well defined in .NET Core (MS.Logging.Extensions) but for 4.x you will have to see what NLog supports and if needs be roll your own.

Update:

By trimming code this much Blazor was breaking .net standard 2 .
From preview7 on, CurrentPrincipal is present but it throws PlatformNotSupportedException when used.