Better way to add language syntax highlighting on file open

[never-give-up-dev]

I have been using a few VS Code plugins for syntax highlighting, but I noticed that each plugin creates its own language server outside of Theia. Instead of spinning up a new external server for every language, how can we bundle this functionality directly into Theia’s build so that syntax highlighting and language support run internally without spawning separate servers?

In the below way i have configured and then start with arg --plugins=local-dir:../../plugins",

  "theiaPluginsDir": "plugins",
  "theiaPlugins": {
    "vscode.html": "https://open-vsx.org/api/vscode/html/1.95.3/file/vscode.html-1.95.3.vsix",
    "vscode.html-language-features": "https://open-vsx.org/api/vscode/html-language-features/1.95.3/file/vscode.html-language-features-1.95.3.vsix",
    }

Thanks for reading up till here, looking for options

[msujew]

Hey @MaheshReddy-05,

unfortunately, I don't think what you're looking for is possible with the existing plugins:

1. Theia cannot influence what the VS Code plugins are doing internally, since they are just plugins.
2. I assume the html-language-features plugin is using a language server to provide the language support. By design, language servers are supposed to run in a separate process (for good reason, see below).

You could write your own plugin for each language that runs inside of the plugin Host (or even the Theia frontend), but this has a few drawbacks:

1. Obviously, quite a lot of work to get to the level of quality of VS Code's builtins (you could fork them though, which would drastically reduce the amount of work required).
2. When a language plugin is slow (i.e. parsing through a large file, etc.), this can quickly become a performance bottleneck, because all plugins run in the single-threaded plugin host process. If a long-running operation blocks the plugin host, no other requests can be resolved. This is why language servers usually run in a separate process.
3. If this were to run inside of the Theia frontend, you could even block up the UI thread, which leads to a really bad user experience.

My question would be, why the plugins spawning new processes is even problematic for your use case?

[never-give-up-dev]

I don't want language-featues i just want syntax highlighting which are part of "vscode.html" for running this we don't need any server so working on stoping plugin-host,

follow up to previous bidning:

when i write rebind(ConnectionContainerModule).toConstantValue(commonHostedConnectionModule); seen
ERROR Error: You are attempting to construct Symbol(HostedPluginServer) in a synchronous way but it has asynchronous dependencies.

and when it bind(ConnectionContainerModule).toConstantValue(commonHostedConnectionModule); seen
ERROR Error: Ambiguous match found for serviceIdentifier: Symbol(HostedPluginServer)

[msujew]

I don't want language-featues i just want syntax highlighting which are part of "vscode.html" for running this we don't need any server so working on stoping plugin-host,

Then, why don't you simply not install the vscode.html-language-features plugin? It only contains the language server for HTML.

[never-give-up-dev]

You are right I did the same. In my plugin, I only kept vscode.html. This was working as expected, but now the plugin-host server is also starting, even though we don’t need any server to run vscode.html

[msujew]

Right, but the process shouldn't use a lot of resources, right? I would recommend to keep the plugin host process to ensure that you can run plugins that require the process, in case you add more plugins in the future (or allow users to install them on their own).

[never-give-up-dev]

Yha it won't take a lot of resources, good suggestion, but I think it’s right now it's unnecessary to run it, let’s stop it.
will follow up this bind, rebind backend log