LSP server launched by extension can't find installed .NET runtime

[swythan]

Environment data

dotnet --info output:

dotnet --info
.NET SDK:
 Version:   7.0.302
 Commit:    990cf98a27

Runtime Environment:
 OS Name:     ubuntu
 OS Version:  22.04
 OS Platform: Linux
 RID:         ubuntu.22.04-x64
 Base Path:   /usr/share/dotnet/sdk/7.0.302/

Host:
  Version:      7.0.5
  Architecture: x64
  Commit:       8042d61b17

.NET SDKs installed:
  3.1.426 [/usr/share/dotnet/sdk]
  5.0.408 [/usr/share/dotnet/sdk]
  6.0.300 [/usr/share/dotnet/sdk]
  7.0.302 [/usr/share/dotnet/sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 3.1.32 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.17 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.16 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.5 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 3.1.32 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.17 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.16 [/usr/share/dotnet/shared/Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.5 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

Other architectures found:
  None

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

VS Code version:

Version: 1.78.2 (system setup)
Commit: b3e4e68a0bc097f0ae7907b217c1119af9e03435
Date: 2023-05-10T14:39:26.248Z
Electron: 22.5.2
Chromium: 108.0.5359.215
Node.js: 16.17.1
V8: 10.8.168.25-electron.0
OS: Windows_NT x64 10.0.19044
Sandboxed: No

C# Extension version:

ms-dotnettools.csdevkit@0.1.83
ms-dotnettools.csharp@2.0.206
ms-dotnettools.vscode-dotnet-runtime@1.6.0

OmniSharp log

Dotnet path: /usr/bin/dotnet
Activating C# standalone...
You must install .NET to run this application.

App: /home/admin/.vscode-server/extensions/ms-dotnettools.csharp-2.0.206/.roslyn/Microsoft.CodeAnalysis.LanguageServer
Architecture: x64
App host version: 7.0.0-preview.7.22362.8
.NET location: Not found

Learn about runtime installation:
https://aka.ms/dotnet/app-launch-failed

Download the .NET runtime:
https://aka.ms/dotnet-core-applaunch?missing_runtime=true&arch=x64&rid=ubuntu.22.04-x64&apphost_version=7.0.0-preview.7.22362.8
[Info  - 12:39:51] Connection to server got closed. Server will restart.
[Error - 12:39:51] Server initialization failed.
  Message: Pending response rejected since connection got disposed
  Code: -32097 
[Error - 12:39:51] Microsoft.CodeAnalysis.LanguageServer client: couldn't create connection to server.
  Message: Pending response rejected since connection got disposed
  Code: -32097 

Steps to reproduce

1. Be on a network that is not connected to the internet
2. Install .NET SDKs & VSCode on Windows machine
3. Create a Linux k8s pod that has .NET SDKs installed from the Ubuntu repo
4. Manually install extensions on Windows machine (win-x64 versions)
5. Manually install VS code remote server and C# extensions on Linux k8s pod (linux-x64 versions)
6. Configure both to not hit the internet to download the .NET runtime
   • Windows

      "dotnetAcquisitionExtension.existingDotnetPath": [  
        {"extensionId": "ms-dotnettools.vscode-dotnet-runtime", "path": "C:\\Program Files\\dotnet\\dotnet.exe"},
        {"extensionId": "ms-dotnettools.csharp", "path": "C:\\Program Files\\dotnet\\dotnet.exe"},
        {"extensionId": "ms-dotnettools.csdevkit", "path": "C:\\Program Files\\dotnet\\dotnet.exe"},
        {"extensionId": "ms-dotnettools.vscodeintellicode-csharp", "path": "C:\\Program Files\\dotnet\\dotnet.exe"},
      ],

   • Linux

      "dotnetAcquisitionExtension.existingDotnetPath": [  
        {"extensionId": "ms-dotnettools.vscode-dotnet-runtime", "path": "/usr/bin/dotnet"},
        {"extensionId": "ms-dotnettools.csharp", "path": "/usr/bin/dotnet"},
        {"extensionId": "ms-dotnettools.csdevkit", "path": "/usr/bin/dotnet"},
        {"extensionId": "ms-dotnettools.vscodeintellicode-csharp", "path": "/usr/bin/dotnet"},
      ],

7. Use Remote-ssh to connect VSCode from Windows to linux/k8s
8. Open a C# file

Expected behavior

The Language Server should start correctly (using the installed .NET runtime) and C# features should work in the editor.

Actual behavior

The language server fails to start, as shown above.

Dotnet path: /usr/bin/dotnet
Activating C# standalone...
You must install .NET to run this application.

App: /home/admin/.vscode-server/extensions/ms-dotnettools.csharp-2.0.206/.roslyn/Microsoft.CodeAnalysis.LanguageServer
Architecture: x64
App host version: 7.0.0-preview.7.22362.8
.NET location: Not found

Additional context

Running the same language server executable from a VS Code Terminal pane works fine:

admin@delta:~/git/delta$ /home/admin/.vscode-server/extensions/ms-dotnettools.csharp-2.0.206/.roslyn/Microsoft.CodeAnalysis.LanguageServer --version
4.7.0-2.23272.9+2244596ee0a1e757ab57881db33829123b6d1da8

With the C# Dev Kit installed I see the same behaviour there, except App host version in the log is 7.0.5.

[Igorgro]

Having the same problem: I've installed .NET runtime and sdk using dotnet-install.sh script, added it to PATH and even set vscode settings to point to existing installation, but this extension still tries to download its own runtime

[dibarbet]

Can you check if the environment variable DOTNET_ROOT is set? If not, does setting it to the installed dotnet location work?
https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-environment-variables#dotnet_root-dotnet_rootx86

[Igorgro]

Yes, setting DOTNET_ROOT helped for me

[swythan]

Thanks.

It seems like something has gone wrong with the way the .NET runtime is installed on our Ubuntu docker image amd /etc/dotnet/install_location was missing. Setting that up correctly worked ofr me.

See:
dotnet/runtime#79237
dotnet/core#7699

[exyi]

I have a very similar problem, but neither DOTNET_ROOT or /etc/dotnet/install_location resolve the issue for me. Interestingly, when I execute ~/.vscode/extensions/ms-dotnettools.csharp-2.0.376-linux-x64/.roslyn/Microsoft.CodeAnalysis.LanguageServer from the terminal, it starts up.

My workaround is to set "dotnet.server.useOmnisharp": true