"dotnet build-server shutdown" equivalent for SharedCompilationId and -pipename?

[KalleOlaviNiemitalo]

With MSBuild.exe, I can set the SharedCompilationId property and later run VBCSCompiler.exe -pipename:"$(SharedCompilationId)" -shutdown to terminate only the Roslyn compiler server that was started for this ID. Is there an equivalent feature for dotnet build-server shutdown?

It looks like the DOTNET_BUILD_PIDFILE_DIRECTORY environment variable could be used for something like that:

sdk/src/Cli/dotnet/BuildServer/BuildServerProvider.cs

Line 15 in 1f6482d

public const string PidFileDirectoryVariableName = "DOTNET_BUILD_PIDFILE_DIRECTORY";

However, from #9302 and #9303, it seems the environment variable is not used by all build servers; and even if they use it for PID files, they might not use it for the actual communication.

[KalleOlaviNiemitalo]

The scenario is that I run automated builds of different projects in parallel under the same user account and want to delete the temporary files of each build after it completes, so I point the TEMP and TMP environment variables to a build-specific directory and delete that directory. The Roslyn compiler server copies analyzer assemblies to the temporary directory and loads them from there. I set the SharedCompilationId MSBuild property to isolate the compiler servers of different builds from each other. When building on .NET Framework, I used VBCSCompiler.exe -pipename:"$(SharedCompilationId)" -shutdown to terminate the compiler server and release the analyzer assemblies so that I was able to delete the temporary directory. When building on .NET SDK 5.0.400 or 6.0.100-rc.2.21505.57, this looks more difficult.

It seems I'd need "C:\Program Files\dotnet\dotnet.exe" exec "C:\Program Files\dotnet\sdk\5.0.400\Roslyn\bincore\VBCSCompiler.dll" -pipename:"$(SharedCompilationId)" -shutdown but dotnet build-server shutdown --vbcscompiler runs it without the -pipename option:

sdk/src/Cli/dotnet/BuildServer/VBCSCompilerServer.cs

Lines 33 to 40 in b87df75

	public void Shutdown()
	{
	var command = _commandFactory
	.Create("exec", new[] { VBCSCompilerPath, "-shutdown" })
	.CaptureStdOut()
	.CaptureStdErr();
	var result = command.Execute();

In the long run, the DOTNET_BUILD_PIDFILE_DIRECTORY approach looks better because it could also isolate different versions of Roslyn from each other, if multiple versions are used during the same build. #9302 has however not been implemented yet.

[baronfel]

We need to codify a spec around build servers and how the SDK will manage them, then go through and ensure the various servers we ship (Roslyn, Razor, MSBuild nodes, etc) adhere to this.

[KalleOlaviNiemitalo]

I'm now using a workaround in which my CI build script executes dotnet msbuild to call an MSBuild target that does <Exec Command='dotnet exec "$(MSBuildBinPath)/Roslyn/bincore/VBCSCompiler.dll" -pipename:"$(SharedCompilationId)" -shutdown' />. I didn't find a better way to locate the VBCSCompiler.dll of the .NET SDK version that was used for the build; it might have rolled forward from the version specified in global.json.