could eglot work with remote project?

[zhongweiy]

hi,
Say a project is on a remote raspberry pi, I have emacs installed on local desktop. When the project file is opened by the desktop emacs (say using tramp), can I get the open file indexed?

Specificly, the project is a cpp project, the toolchain is only availabe on the remote pi. So the lsp server is better running on the remote pi. Can I get it work by eglot?

Thanks!

[joaotavora]

Hi, this is a very good question.

When the project file is opened by the desktop emacs (say using tramp), can I get the open file indexed?

Yes, I suppose so. Although it depends on how the server interprets the resulting file URLs. Eglot could, if the spec allows it (or even if it doesn't) implement a customization point for this.

So the lsp server is better running on the remote pi.

You can, assuming you have TCP/IP on the pi and start the server with this option. See the docstring of eglot-server-programs for details.

[zhongweiy]

Thanks! I'll give a try.

[slippycheeze]

FWIW, I'd be ... quite in favor, shall we say, of this happening. For "local", as in stdio style, servers, switching to just using start-file-process instead of start-process would be sufficient; interpreting the filenames reported as (expand-file-name FROM-SERVER default-directory) in the file buffer should work to get a tramp-suitable name for them -- or you can use file-remote-p on the buffer filename to get a "truthy" value that is the remote host prefix. (eg: for tramp /ssh:example.com:~/src that'd return /ssh:example.com:, which you can paste to the front of an absolute remote path.

I'm glad to hear you are open to the idea, as depending how things go, I may end up with submittable patches; do you require confirmation of FSF contribution papers, or another agreement for them?

Please do not take this as any sort of promise about when, or if, I will do anything, though. :/

[joaotavora]

switching to just using start-file-process instead of start-process

This comment made me realize that this is better implemented in Emacs's jsonrpc.el, rather than in eglot.el (although it could be experimentally implemented in eglot).

do you require confirmation of FSF contribution papers,

I require that you start the copyright paperwork process, but you can contribute before you get the official confirmation.

[zhongweiy]

@joaotavora

Although it depends on how the server interprets the resulting file URLs. Eglot could, if the spec allows it (or even if it doesn't) implement a customization point for this.

By following your suggestion, I took a try by providing a LSP remote server (a Cquery server) to Eglot and converting the tramp file URL to local file URL back and forth. And I check some functions (xref-find-definitions) works with my ugly hacking patch to Eglot.

I have not tried the approach @slippycheeze mentioned (start the Cquery server by start-file-process seems much more convenient.)

Here are some details:

1. Get Cquery installed on my remote server (192.168.1.50). And run it by nc -l -p 5010 -e cquery to redirect stdout to socket.
2. Open a cpp file in the remote server by the local desktop Emacs by tramp ssh. And start the Eglot with server: 192.168.1.50:5010. Done.