Hacking on lsp-elixir--get-root

init.el

;; ...

(require-package 'elixir-mode)
(require-package 'lsp-mode)
(require-package 'company-lsp)
(require 'lsp-elixir)

(add-hook 'elixir-mode-hook #'lsp-elixir-enable)

(require 'company)
(push 'company-lsp company-backends)

;; ...

lisp__lsp-elixir.el

(require 'lsp-mode)
(require 'lsp-common)

(defconst lsp-elixir--get-root
  (lsp-make-traverser #'(lambda (dir)
                          (directory-files dir nil "mix.exs"))))

(lsp-define-stdio-client
 lsp-elixir
 "elixir"
 lsp-elixir--get-root
 '("sh" "/Users/rodrigues/.elixir-ls-server/language_server.sh"))

(provide 'lsp-elixir)

setup

#! /usr/bin/env elixir

version = "0.2.14"
repo = "https://github.com/JakeBecker/elixir-ls"
release_url = "#{repo}/releases/download/v#{version}/elixir-ls.zip"
release_path = "~/.elixir-ls-server" |> Path.expand()
zip_path = "#{release_path}/server.zip"

unless release_path |> File.dir?() do
  System.cmd("mkdir", ["-p", release_path])
  System.cmd("curl", ["-fSL", release_url, "-o", zip_path])
  :zip.unzip(to_charlist(zip_path), cwd: to_charlist(release_path))
end