efm-langserver

General purpose Language Server that can use specified error message format generated from specified command. This is useful for editing code with linter.

efm

Installation
Usage
Client Setup
License
Author

Installation

go install github.com/mattn/efm-langserver@latest

or via Homebrew:

brew install efm-langserver

Usage

Usage of efm-langserver:
  -c string
        path to config.yaml
  -d    dump configuration
  -logfile string
        logfile
  -loglevel int
        loglevel (default 1)
  -q    Run quieter
  -v    Print the version

Configuration

Configuration can be done with either a config.yaml file, or through a DidChangeConfiguration notification from the client. DidChangeConfiguration can be called any time and will overwrite only provided properties.

DidChangeConfiguration only supports V2 configuration and cannot set LogFile.

efm-langserver does not include formatters/linters for any languages, you must install these manually, e.g.

lua: LuaFormatter
python: yapf isort
vint for Vim script
markdownlint-cli for Markdown
etc…

InitializeParams

Because the configuration can be updated on the fly, capabilities might change throughout the lifetime of the server. To enable support for capabilities that will be available later, set them in the InitializeParams

Example

{
    "initializationOptions": {
        "documentFormatting": true,
        "documentRangeFormatting": true,
        "hover": true,
        "documentSymbol": true,
        "codeAction": true,
        "completion": true
    }
}

Example for config.yaml

Location of config.yaml is:

UNIX: $XDG_CONFIG_HOME/efm-langserver/config.yaml or $HOME/.config/efm-langserver/config.yaml
Windows: %APPDATA%\efm-langserver\config.yaml

Below is example for config.yaml for Windows. Please see schema.md for full documentation of the available options.

version: 2
root-markers:
  - .git/
lint-debounce: 1s
commands:
  - command: notepad
    arguments:
      - ${INPUT}
    title: メモ帳

tools:
  any-excitetranslate: &any-excitetranslate
    hover-command: 'excitetranslate'
    hover-stdin: true

  blade-blade-formatter: &blade-blade-formatter
    format-command: 'blade-formatter --stdin'
    format-stdin: true

  css-prettier: &css-prettier
    format-command: './node_modules/.bin/prettier ${--tab-width:tabWidth} ${--single-quote:singleQuote} --parser css'

  csv-csvlint: &csv-csvlint
    lint-command: 'csvlint'

  dockerfile-hadolint: &dockerfile-hadolint
    lint-command: 'hadolint'
    lint-formats:
      - '%f:%l %m'

  eruby-erb: &eruby-erb
    lint-debounce: 2s
    lint-command: 'erb -x -T - | ruby -c'
    lint-stdin: true
    lint-offset: 1
    format-stdin: true
    format-command: htmlbeautifier

  gitcommit-gitlint: &gitcommit-gitlint
    lint-command: 'gitlint'
    lint-stdin: true
    lint-formats:
      - '%l: %m: "%r"'
      - '%l: %m'

  html-prettier: &html-prettier
    format-command: './node_modules/.bin/prettier ${--tab-width:tabWidth} ${--single-quote:singleQuote} --parser html'

  javascript-eslint: &javascript-eslint
    lint-command: 'eslint -f visualstudio --stdin --stdin-filename ${INPUT}'
    lint-ignore-exit-code: true
    lint-stdin: true
    lint-formats:
      - "%f(%l,%c): %tarning %m"
      - "%f(%l,%c): %rror %m"

  json-fixjson: &json-fixjson
    format-command: 'fixjson'

  json-jq: &json-jq
    lint-command: 'jq .'

  json-prettier: &json-prettier
    format-command: './node_modules/.bin/prettier ${--tab-width:tabWidth} --parser json'

  lua-lua-format: &lua-lua-format
    format-command: 'lua-format -i'
    format-stdin: true

  make-checkmake: &make-checkmake
    lint-command: 'checkmake'
    lint-stdin: true

  markdown-markdownlint: &markdown-markdownlint
    lint-command: 'markdownlint -s -c %USERPROFILE%\.markdownlintrc'
    lint-stdin: true
    lint-formats:
      - '%f:%l %m'
      - '%f:%l:%c %m'
      - '%f: %l: %m'

  markdown-pandoc: &markdown-pandoc
    format-command: 'pandoc -f markdown -t gfm -sp --tab-stop=2'

  mix_credo: &mix_credo
    lint-command: "mix credo suggest --format=flycheck --read-from-stdin ${INPUT}"
    lint-stdin: true
    lint-formats:
      - '%f:%l:%c: %t: %m'
      - '%f:%l: %t: %m'
    root-markers:
      - mix.lock
      - mix.exs

  perl-perlcritic: &perl-perlcritic
    lint-command: 'perlcritic --nocolor -3 --verbose "%l:%c %m\n"'
    lint-ignore-exit-code: true
    lint-formats:
      - '%l:%c %m'

  perl-perltidy: &perl-perltidy
    format-command: "perltidy -b"
    format-stdin: true

  php-phpstan: &php-phpstan
    lint-command: './vendor/bin/phpstan analyze --error-format raw --no-progress'

  php-psalm: &php-psalm
    lint-command: './vendor/bin/psalm --output-format=emacs --no-progress'
    lint-formats:
      - '%f:%l:%c:%trror - %m'
      - '%f:%l:%c:%tarning - %m'

  prettierd: &prettierd
    format-command: >
      prettierd ${INPUT} ${--range-start=charStart} ${--range-end=charEnd} \
        ${--tab-width=tabSize}
    format-stdin: true
    root-markers:
      - .prettierrc
      - .prettierrc.json
      - .prettierrc.js
      - .prettierrc.yml
      - .prettierrc.yaml
      - .prettierrc.json5
      - .prettierrc.mjs
      - .prettierrc.cjs
      - .prettierrc.toml

  python-autopep8: &python-autopep8
    format-command: 'autopep8 -'
    format-stdin: true

  python-black: &python-black
    format-command: 'black --quiet -'
    format-stdin: true

  python-flake8: &python-flake8
    lint-command: 'flake8 --stdin-display-name ${INPUT} -'
    lint-stdin: true
    lint-formats:
      - '%f:%l:%c: %m'

  python-isort: &python-isort
    format-command: 'isort --quiet -'
    format-stdin: true

  python-mypy: &python-mypy
    lint-command: 'mypy --show-column-numbers'
    lint-formats:
      - '%f:%l:%c: %trror: %m'
      - '%f:%l:%c: %tarning: %m'
      - '%f:%l:%c: %tote: %m'

  python-pylint: &python-pylint
    lint-command: 'pylint --output-format text --score no --msg-template {path}:{line}:{column}:{C}:{msg} ${INPUT}'
    lint-stdin: false
    lint-formats:
      - '%f:%l:%c:%t:%m'
    lint-offset-columns: 1
    lint-category-map:
      I: H
      R: I
      C: I
      W: W
      E: E
      F: E

  python-yapf: &python-yapf
    format-command: 'yapf --quiet'
    format-stdin: true

  rst-lint: &rst-lint
    lint-command: 'rst-lint'
    lint-formats:
      - '%tNFO %f:%l %m'
      - '%tARNING %f:%l %m'
      - '%tRROR %f:%l %m'
      - '%tEVERE %f:%l %m'

  rst-pandoc: &rst-pandoc
    format-command: 'pandoc -f rst -t rst -s --columns=79'

  sh-shellcheck: &sh-shellcheck
    lint-command: 'shellcheck -f gcc -x'
    lint-source: 'shellcheck'
    lint-formats:
      - '%f:%l:%c: %trror: %m'
      - '%f:%l:%c: %tarning: %m'
      - '%f:%l:%c: %tote: %m'

  sh-shfmt: &sh-shfmt
    format-command: 'shfmt -ci -s -bn'
    format-stdin: true

  vim-vint: &vim-vint
    lint-command: 'vint -'
    lint-stdin: true
    lint-formats:
      - '%f:%l:%c: %m'

  yaml-yamllint: &yaml-yamllint
    lint-command: 'yamllint -f parsable -'
    lint-stdin: true

languages:
  blade:
    - <<: *blade-blade-formatter

  css:
    - <<: *css-prettier

  csv:
    - <<: *csv-csvlint

  dockerfile:
    - <<: *dockerfile-hadolint

  elixir:
    - <<: *mix_credo

  eruby:
    - <<: *eruby-erb

  gitcommit:
    - <<: *gitcommit-gitlint

  html:
    - <<: *html-prettier

  javascript:
    - <<: *javascript-eslint
    - <<: *prettierd

  json:
    - <<: *json-fixjson
    - <<: *json-jq
    # - <<: *json-prettier

  lua:
    - <<: *lua-lua-format

  make:
    - <<: *make-checkmake

  markdown:
    - <<: *markdown-markdownlint
    - <<: *markdown-pandoc

  perl:
    - <<: *perl-perltidy
    - <<: *perl-perlcritic

  php:
    - <<: *php-phpstan
    - <<: *php-psalm

  python:
    - <<: *python-black
    - <<: *python-flake8
    - <<: *python-isort
    - <<: *python-mypy
    # - <<: *python-autopep8
    # - <<: *python-yapf

  rst:
    - <<: *rst-lint
    - <<: *rst-pandoc

  sh:
    - <<: *sh-shellcheck
    - <<: *sh-shfmt

  vim:
    - <<: *vim-vint

  yaml:
    - <<: *yaml-yamllint

  =:
    - <<: *any-excitetranslate

If you want to debug output of commands:

version: 2
log-file: /path/to/output.log
log-level: 1

Example for DidChangeConfiguration notification

{
    "settings": {
        "rootMarkers": [".git/"],
        "languages": {
            "lua": {
                "formatCommand": "lua-format -i",
                "formatStdin": true
            }
        }
    }
}

Client Setup

Configuration for vim-lsp

augroup LspEFM
  au!
  autocmd User lsp_setup call lsp#register_server({
      \ 'name': 'efm-langserver',
      \ 'cmd': {server_info->['efm-langserver', '-c=/path/to/your/config.yaml']},
      \ 'allowlist': ['vim', 'eruby', 'markdown', 'yaml'],
      \ })
augroup END

vim-lsp-settings provide installer for efm-langserver.

Configuration for coc.nvim

coc-settings.json

  // languageserver
  "languageserver": {
    "efm": {
      "command": "efm-langserver",
      "args": [],
      // custom config path
      // "args": ["-c", "/path/to/your/config.yaml"],
      "filetypes": ["vim", "eruby", "markdown", "yaml"]
    }
  },

Configuration for Eglot (Emacs)

Add to eglot-server-programs with major mode you want.

(with-eval-after-load 'eglot
  (add-to-list 'eglot-server-programs
    `(markdown-mode . ("efm-langserver"))))

Configuration for neovim builtin LSP with nvim-lspconfig

Neovim’s built-in LSP client sends DidChangeConfiguration, so config.yaml is optional.

init.lua example (settings follows schema.md):

require "lspconfig".efm.setup {
    init_options = {documentFormatting = true},
    settings = {
        rootMarkers = {".git/"},
        languages = {
            lua = {
                {formatCommand = "lua-format -i", formatStdin = true}
            }
        }
    }
}

You can get premade tool definitions from creativenull/efmls-configs-nvim:

lua = {
  require('efmls-configs.linters.luacheck'),
  require('efmls-configs.formatters.stylua'),
}

If you define your own, make sure to define as table:

lua = {
    {formatCommand = "lua-format -i", formatStdin = true}
}
-- NOT
lua = {
    formatCommand = "lua-format -i", formatStdin = true
}

-- and for multiple formatters, add to the table
lua = {
    {formatCommand = "lua-format -i", formatStdin = true},
    {formatCommand = "lua-pretty -i"}
}

Configuration for Helix

~/.config/helix/languages.toml

[language-server.efm]
command = "efm-langserver"

[[language]]
name = "typescript"
language-servers = [
  { name = "efm", only-features = [ "diagnostics", "format" ] },
  { name = "typescript-language-server", except-features = [ "format" ] }
]

Configuration for VSCode

Generic LSP Client for VSCode

Example settings.json (change to fit your local installs):

{
  "glspc.languageId": "lua",
  "glspc.serverCommand": "/Users/me/.local/share/nvim/mason/bin/efm-langserver",
  "glspc.pathPrepend": "/Users/me/.local/share/rtx/installs/python/3.11.4/bin:/Users/me/.local/share/rtx/installs/node/20.3.1/bin",
}

License

MIT

Author

Yasuhiro Matsumoto (a.k.a. mattn)

This site is open source. Improve this page.