instrumental/bin/webpack-dev-server

#!/usr/bin/env ruby
$stdout.sync = true

require "shellwords"
require "yaml"
require "socket"

ENV["RAILS_ENV"] ||= "development"
RAILS_ENV = ENV["RAILS_ENV"]

ENV["NODE_ENV"] ||= RAILS_ENV
NODE_ENV = ENV["NODE_ENV"]

APP_PATH          = File.expand_path("../", __dir__)
CONFIG_FILE       = File.join(APP_PATH, "config/webpacker.yml")
NODE_MODULES_PATH = File.join(APP_PATH, "node_modules")
WEBPACK_CONFIG    = File.join(APP_PATH, "config/webpack/#{NODE_ENV}.js")

DEFAULT_LISTEN_HOST_ADDR = NODE_ENV == 'development' ? 'localhost' : '0.0.0.0'

def args(key)
  index = ARGV.index(key)
  index ? ARGV[index + 1] : nil
end

begin
  dev_server = YAML.load_file(CONFIG_FILE)[RAILS_ENV]["dev_server"]

  HOSTNAME          = args('--host') || dev_server["host"]
  PORT              = args('--port') || dev_server["port"]
  HTTPS             = ARGV.include?('--https') || dev_server["https"]
  DEV_SERVER_ADDR   = "http#{"s" if HTTPS}://#{HOSTNAME}:#{PORT}"
  LISTEN_HOST_ADDR  = args('--listen-host') || DEFAULT_LISTEN_HOST_ADDR

rescue Errno::ENOENT, NoMethodError
  $stdout.puts "Webpack dev_server configuration not found in #{CONFIG_FILE}."
  $stdout.puts "Please run bundle exec rails webpacker:install to install webpacker"
  exit!
end

begin
  server = TCPServer.new(LISTEN_HOST_ADDR, PORT)
  server.close

rescue Errno::EADDRINUSE
  $stdout.puts "Another program is running on port #{PORT}. Set a new port in #{CONFIG_FILE} for dev_server"
  exit!
end

# Delete supplied host, port and listen-host CLI arguments
["--host", "--port", "--listen-host"].each do |arg|
  ARGV.delete(args(arg))
  ARGV.delete(arg)
end

env = { "NODE_PATH" => NODE_MODULES_PATH.shellescape }

cmd = [
  "#{NODE_MODULES_PATH}/.bin/webpack-dev-server", "--progress", "--color",
  "--config", WEBPACK_CONFIG,
  "--host", LISTEN_HOST_ADDR,
  "--public", "#{HOSTNAME}:#{PORT}",
  "--port", PORT.to_s
] + ARGV

Dir.chdir(APP_PATH) do
  exec env, *cmd
end