Assembly loading - PlatformNotSupportedException

[Benjiinator]

I am in the middle of migrating a large project from .net framework -> .net core 3.1 and during the process i am encountering "Microsoft.Data.SqlClient is not supported on this platform".

My project solution consists of the following:

• .Net core 3.1 program that can load and run plugin modules through assembly.
• .Net standard 2.0 plugin modules with dependecies (1 of which has a dependency on Microsoft.Data.SqlClient)

I have read the FAQ point 11 which refers to what sounds like my problem - however, i am still oblivious as to how i am to solve the problem.

[cheenamalhotra]

Hi @Benjiinator

Is it possible to wrap a repro application and upload it here to take a closer look?
It does look like what is mentioned in point 11 may apply to your case.

[Benjiinator]

Hi @cheenamalhotra

I will attempt creating one and get back to you.

[Benjiinator]

Hi @cheenamalhotra
I have created a repro application and the issue still persists.
I have set it up to build the needed librarys to the path "C:/AssemblyLoading".

When publishing the exe itself i used the following settings:

• Deployment mode: self contained
• Target Runtime: win-x64
• Produce single file: true

[cheenamalhotra]

Hi @Benjiinator

If you specify "RuntimeIdentifier" in your PluginShared.csproj, that seems to resolve the issue:

I now see correct DLL being referenced in *.deps.json files:

[Benjiinator]

Hi @cheenamalhotra

After setting the "RuntimeIdentifier", cleaning, rebuilding and publishing the application the issue is still present.

[cheenamalhotra]

Could you also specify the same in DemoPlugin.csproj and try again?

It seems that project also needs a RuntimeIdentifier to yield this:

[Benjiinator]

Hi @cheenamalhotra

This resolved my issue.

Many thanks for the help - it is much appreciated.

[Benjiinator]

Hi @cheenamalhotra

After implementing your solution i now am getting the following error: "Unable to load DLL 'Microsoft.Data.SqlClient.SNI.dll' or one of its dependencies: The specified module could not be found. (0x8007007E)" when i attempt running it on my production environment.

[cheenamalhotra]

Hi @Benjiinator

We depend on native runtime library "Microsoft.Data.SqlClient.SNI.dll" which could usually be found on runtimes directly from where all runtime DLLs are loaded. If you haven't provided Execute permissions there (common possibility in Production env), it might be the reason your application will have issues. Please take a look at #385 (comment) and related discussion for more details.

[Benjiinator]

Hi @cheenamalhotra

I'm not quite sure how to proceed with this issue, my application is not running on iis - it is a windows service running on an administrator account.
The directory of the application does have Read & Execute permissions for the administrator account - I must be missing something.

[cheenamalhotra]

Runtime native DLLs are fetched from NuGet Cache location in .NET Core, so you will need to verify permissions to that folder too.

[Benjiinator]

Hi @cheenamalhotra

A NuGet cache is not present on my production environment - i looked for it under "%localappdata%" + "/NuGet/Cache" but the NuGet folder is not present.

[cheenamalhotra]

Hi @Benjiinator

You may find your NuGet cache location by running this tool and verify if you have required permissions:
dotnet nuget locals (details)

[Benjiinator]

Hi @cheenamalhotra

After running the tool i got found out the following:

• http-cache: C:\Users\Administrator\AppData\Local\NuGet\v3-cache - path does not exist
• global-packages: C:\Users\Administrator.nuget\packages\ - path does not exist
• temp: C:\Users\Administrator\AppData\Local\Temp\2\NuGetScratch - administrator account has all permissions
• plugins-cache: C:\Users\Administrator\AppData\Local\NuGet\plugins-cache - path does not exist

[Benjiinator]

Hi @cheenamalhotra

Any ideas what else could be wrong when the cache locations either does not exist on the production environment or exists and has the proper permissions?

[Benjiinator]

Hi @cheenamalhotra

Any updates on this issue? - it is the last thing keeping us from fully migrating to .Net Core.

[Benjiinator]

@cheenamalhotra After upgrading from .Net Core 3.1 to .Net 5.0 the issue disappeared.
Thanks for your help though - it is greatly appreciated