Nuget restore fails on VSO 2017 build for CORE packages

Question

I have previously created and built a simple .net core nuget package and pushed it to our internal nuget (hosted inside our VSO). Now I wanted to reference it from another core project. This worked fine locally.

I then go onto defining my build. Here are the details:

• Agent is "Hosted VS2017"
• Process
  • Nuget Installer (Version 3.5, pointed at my solution file, nuget.config contains my package sources)
  • Thats it! We never get any further

When I run the build I get this error on the Nuget Installer bit:

[command]C:\a\_tasks\....\NuGet\3.5.0\NuGet.exe restore -NonInteractive C:\a\1\s\...sln -ConfigFile C:\a\1\s\...\nuget.config
Failed to load msbuild Toolset
Could not load file or assembly 'Microsoft.Build, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. 

Things I've Tried:

• If the nuget version is lower than 3.5 I get a 401 unauthorized
• If the nuget version is lower than 3.5 and I don't reference a dotnetcore nuget it works
• I added my own credentials to the packageStoreCredentials section of the nuget.config with no effect (I am an admin on VSO)
• I tried using nuget 4 by including its exe in the checkin and referencing that from the Nuget Installer, but I then get "Error: Iac.Repository/nuget.exe failed. spawn Iac.Repository/nuget.exe ENOENT"

Thanks for any help!

Answer 1

You need to use NuGet 4.0 instead of 3.5 since your project is based on VS2017.

Now NuGet 4.0 is available for NuGet Installer task, so you can select the version directly and needn’t checkin the version to your source code.

For some VSTS accounts don't show nuget 4.0, I creates a new issue here, you can follow up.

Another way to use NuGet 4.0 for TFVC project:

1. Checkin the nugget 4.0 in source code, such as nuget4.0.exe.
2. In Get source step, map nuget4.0.exe.

3. In nugget installer task, specify nugget.exe path as $(build.sourcesDirectory)/nuget4.0.exe.

Answer 2

I had this issue too and found this thread.

After reviewing Marina's comments, I was able to get it working. All I did was alter the path based on the comments.

$(Build.SourcesDirectory)\Builds\Tools\nuget.exe