Feature: automatic server installation

[yyoncho]

We could use https://gitlab.com/jabranham/system-packages to automatically download and install language servers that have published their packages(npm/gem/pip).

NB: the servers that does not have installation package won't be handled by this feature.

(cc @jabranham)

[seagle0128]

Some comments form my experience. I tried this package with use-package a few months ago. It's unable to handle all scenarios on all platforms, especially for Windows and sudo with Linux. So it's a good feature but need more cautions.

[jabranham]

@seagle0128 What issues did you run into with sudo on linux? Would you mind opening a new issue for it?

[seagle0128]

@jabranham I remember that some commands need sudo privileges while others don't. During Emacs startup, there will be many prompts to interrupt, and really annoying! Especially on remote development environment which didn't install all packages :-(

[yyoncho]

We may use the vscode package for the installation, I am planning to do that for dap-mode.

[easbarba]

@jabranham
Ok!

@seagle0128
Just tried system-packages today, it is simpler (no prompt at startup), and it correctly guess by checking the distro package if its needs sudo to install packages!

I had just a minor annoyance, if you have guix or nix installed in your distro it prefer those two package-manager rather than the distro default (eg: instead of apt it installs with guix)...

Opening a issue late!

[seagle0128]

@eubarbosa No password prompt for sudo on Linux?

I used system-packages for legacy lsp-mode to try installing all servers at startup. I think the current situation is different. If the servers are installed and started on-demand, the annoyances I met should not exist.

[tam5]

I'm all for auto installation of language servers, with the condition that a user could customize this to turn it off and specify the language server they want to use directly.

Also, I think a quicker/easier fix, should this take a little while to get done, would be to just add more detailed and exact instructions for installing each language server, so someone new to the idea of lsp would still be able to get up and running quickly

[alanz]

I think providing a pointer to install instructions makes more sense. Some language servers are fairly complex to install, and may involve interaction with the system package manager.

[yyoncho]

@alanz that's correct, I will update the feature description. In general I was referencing the following servers:

1. Servers that are available as a package like (pyls)
2. Servers that are packaged in VSCode extension(php).

[Pitometsu]

Lsp server may depend on per-project environment requirements (like version).
That's why system wide installation is a wrong way. There's nix environments for that and ad-hoc solutions like development in docker.

[yyoncho]

@Pitometsu I closed as wont fix #440 which was intended to be used for testing purposes. Maybe we could have what you are suggesting as a separate issue?

In this PR I am looking for more lightweight solution, similar to what you have in vscode where you just download the extension and it works, no other configurations are needed.

[easbarba]

@yyoncho

VSCode offers to "install" extensions just like lsp-java as we open a .xxx file!

That seems a good way to ask to install servers!