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Flux LSP

LICENSE Slack Status

An implementation of the Language Server Protocol for the Flux language.

LSP Development

  • LSP development requires rust version of 1.40.0 or newer.
  • run tests with cargo test

Installing command line server

cargo install --locked --git

NOTE: previously, flux-lsp was installed via npm. If you have installed flux-lsp with this method, please remove that version before installing this one.

This will allow you to run an LSP instance with the command flux-lsp. Like other command-line lsp servers, communication with the lsp server is via stdin/stdout. To use this utility in your editor of choice, you'll need to use a plugin that supports command-line lsp servers.

If you find a plugin for your editor that doesn't work with flux-lsp, please file a bug.

Vim setup

There are a lot of plugins that are capable of running language servers. This section will cover the one we use or know about.

In any case, you need to recognize the filetype. This is done looking at the file extension, in our case .flux. You should place this in your vimrc file:

" Flux file type
au BufRead,BufNewFile *.flux        set filetype=flux

with neovim-lspconfig

Requires neovim-lspconfig

in your init.vim


See here for more details.

with vim-lsp

Requires vim-lsp

in your .vimrc

let g:lsp_diagnostics_enabled = 1

if executable('flux-lsp')
    au User lsp_setup call lsp#register_server({
        \ 'name': 'flux lsp',
        \ 'cmd': {server_info->[&shell, &shellcmdflag, 'flux-lsp']},
        \ 'whitelist': ['flux'],
        \ })

autocmd FileType flux nmap gd <plug>(lsp-definition)

with vim-coc

Requires vim-coc. vim-coc uses a coc-settings.json file and it is located in your ~/.vim directory. In order to run the flux-lsp you need to add the flux section in the languageserver.

  "languageserver": {
      "flux": {
        "command": "flux-lsp",
        "filetypes": ["flux"]

If you need to debug what flux-lsp is doing, you can configure it to log to /tmp/fluxlsp:

  "languageserver": {
      "flux": {
        "command": "flux-lsp",
        "args": ["-l", "/tmp/fluxlsp"],
        "filetypes": ["flux"]

with webpack

This package is distributed as a wasm file, and since wasm files cannot be included in the main bundle, you need to import the library a little differently:

    .then(({Server}) => {
        let server = new Server(false);
        // The LSP server is now ready to use

Also ensure that the wasm file is not being parsed by any file loader plugins, as this will interfere with it's proper instantiation.

Supported LSP features

  • completionItem/resolve
  • initialize
  • shutdown
  • textDocument/completion
  • textDocument/definition
  • textDocument/didChange
  • textDocument/didOpen
  • textDocument/didSave
  • textDocument/documentHighlight
  • textDocument/documentSymbol
  • textDocument/foldingRange
  • textDocument/hover
  • textDocument/references
  • textDocument/rename