Run FSAC inside a Docker container

[nojaf]

Hi, I'm wondering if it would be possible for the ionide extension to connect to a running Docker container with .NET in it.
So imagine I spin a container and keep it running in the background:

docker run -t -d --rm --name dotnet-container mcr.microsoft.com/dotnet/sdk:5.0-focal

I map the volumes and such and then the FASC is started from there.
Expose the right ports and connection from the editor.
Would such a thing be feasible?

[baronfel]

I think it could be possible. VSCode lets us spawn a LanguageServer and interact with it via a type called ServerOptions, which is defined here.

export type ServerOptions = Executable | { run: Executable; debug: Executable; } | { run: NodeModule; debug: NodeModule } | NodeModule | (() => Promise<ChildProcess | StreamInfo | MessageTransports | ChildProcessInfo>);

Of all of these options, I think it would be pretty simple to return a StreamInfo here:

export interface StreamInfo {
	writer: NodeJS.WritableStream;
	reader: NodeJS.ReadableStream;
	detached?: boolean;
}

where the WritableStream would be mapped to the stdin of your container, and the Readable stream would be mapped to the stdout of your container. I think if you can get the stdin/stdout of the external process somehow that might also work.

[nojaf]

Would it not be easier to "connect" to a language server instead of spawning one?
I'm going to make some assumptions but:

• FSAC runs some sort of webserver to deal with all the LSP protocols?
• Could I just not then connect to the existing running server instead of spawning one myself?
• The fact that I'm going to run FSAC inside a docker container should be transparent for the extension, as in it does not need to know right?

[baronfel]

That's what I'm saying: the mechanism to connect to an already running server is to provide vscode with a pair of stream representing the input to that server and the output from that server.

You're not necessarily spawning it, spawning a new server is just one of the options (most of the other serveroptions in the union I mentioned deal with explicitly spawning new processes).

[nojaf]

Ok, I had a different idea of how that part worked.
Would it be as "simple" as extending

ionide-vscode-fsharp/src/Core/LanguageService.fs

Lines 648 to 692 in 9cad0e4

	let getOptions () = promise {
	let dotnetNotFound () = promise {
	let msg = """
	Cannot start .NET Core language services because `dotnet` was not found.
	Consider:
	* setting the `FSharp.dotnetRoot` settings key to a directory with a `dotnet` binary,
	* including `dotnet` in your PATH, or
	* installing .NET Core into one of the default locations.
	"""
	let! result = vscode.window.showErrorMessage(msg)
	return failwith "no `dotnet` binary found"
	}
	let backgroundSymbolCache = "FSharp.enableBackgroundServices" |> Configuration.get true
	let fsacAttachDebugger = "FSharp.fsac.attachDebugger" |> Configuration.get false
	let fsacNetcorePath = "FSharp.fsac.netCoreDllPath" |> Configuration.get ""
	let fsacSilencedLogs = "FSharp.fsac.silencedLogs" |> Configuration.get [||]
	let verbose = "FSharp.verboseLogging" |> Configuration.get false
	let spawnNetCore dotnet =
	let fsautocompletePath =
	if String.IsNullOrEmpty fsacNetcorePath then VSCodeExtension.ionidePluginPath () + "/bin/fsautocomplete.dll"
	else fsacNetcorePath
	printfn "FSAC (NETCORE): '%s'" fsautocompletePath
	let args =
	[
	yield fsautocompletePath
	if fsacAttachDebugger
	then
	yield "--attachdebugger"
	yield "--wait-for-debugger"
	if backgroundSymbolCache then yield "--background-service-enabled"
	if verbose then yield "--verbose"
	if fsacSilencedLogs <> null && fsacSilencedLogs.Length > 0
	then
	yield "--filter"
	yield fsacSilencedLogs |> String.concat ","
	] |> ResizeArray
	createObj [
	"command" ==> dotnet
	"args" ==> args
	"transport" ==> 0
	]

?

[Krzysztof-Cieslak]

Have you tried dev containers? (https://code.visualstudio.com/docs/remote/containers)

[Krzysztof-Cieslak]

You may try using dev containers to connect to docker running inside gitpod instance.

[nojaf]

I'm using Theia editor at the moment (as there is current is a bug with vscode in gitpod) so I cannot check whether dev containers are even a thing there.
This honestly seems like a very tied to vscode type of functionality.

[Krzysztof-Cieslak]

It's not tied to vscode any more than Ionide itself, it's just an extension. It should probably run fine in gitpod/theia 🤷‍♂️

[nojaf]

Do you have any proof of that? The branding on the docs is very on the nose here:

The Visual Studio Code Remote - Containers extension lets you use a Docker container as a full-featured development environment.

It literally is a extension provided by MSFT: https://marketplace.visualstudio.com/items?itemName=ms-vscode-remote.remote-containers
Nowhere to be found on https://open-vsx.org/

[Krzysztof-Cieslak]

Ionide up until yesterday was also not found on open-vsx. And yet it worked fine on GitPod for years.