Refactor and test IPv6 support in websocket server

script/websocket-server.rb

@@ -5,7 +5,7 @@ $LOAD_PATH << './lib'
 require 'rubygems'
 
 # load rails env
-dir = File.expand_path(File.join(File.dirname(__FILE__), '..'))
+dir = File.expand_path('..', __dir__)
 Dir.chdir dir
 RAILS_ENV = ENV['RAILS_ENV'] || 'development'
 
@@ -38,8 +38,8 @@ def after_fork(dir)
     file.sync = true
   end
 
-  $stdout.reopen( "#{dir}/log/websocket-server_out.log", 'w')
-  $stderr.reopen( "#{dir}/log/websocket-server_err.log", 'w')
+  $stdout.reopen( "#{dir}/log/websocket-server_out.log", 'w').sync = true
+  $stderr.reopen( "#{dir}/log/websocket-server_err.log", 'w').sync = true
 end
 
 before_fork
@@ -70,7 +70,7 @@ OptionParser.new do |opts|
     @options[:p] = p
   end
   opts.on('-b', '--bind [OPT]', 'bind address') do |b|
-    @options[:b] = b
+    @options[:b] = IPAddr.new(b).to_s
   end
   opts.on('-s', '--secure', 'enable secure connections') do |s|
     @options[:s] = s
@@ -92,29 +92,29 @@ if ARGV[0] != 'start' && ARGV[0] != 'stop'
 end
 
 if ARGV[0] == 'stop'
-  puts "Stopping websocket server (pid:#{@options[:i]})"
+  pid = File.read(@options[:i]).to_i
+  puts "Stopping websocket server (pid: #{pid})"
 
-  # read pid
-  pid = File.open( @options[:i].to_s  ).read
-  pid.gsub!(/\r|\n/, '')
+  # IMPORTANT: Use SIGTERM (15), not SIGKILL (9)
+  # Daemons.rb cleans up the PID file automatically on termination;
+  # SIGKILL ends the process immediately and bypasses cleanup.
+  # See https://major.io/2010/03/18/sigterm-vs-sigkill/ for more.
+  Process.kill(:SIGTERM, pid)
 
-  # kill
-  Process.kill( 9, pid.to_i )
   exit
 end
 
 if ARGV[0] == 'start' && @options[:d]
-  puts "Starting websocket server on #{@options[:b]}:#{@options[:p]} (secure:#{@options[:s]},pid:#{@options[:i]})"
+  puts "Starting websocket server on #{@options[:b]}:#{@options[:p]} (secure: #{@options[:s]}, pidfile: #{@options[:i]})"
 
-  Daemons.daemonize
+  # Use Daemons.rb's built-in facility for generating PID files
+  Daemons.daemonize(
+    app_name: File.basename(@options[:i], '.pid'),
+    dir_mode: :normal,
+    dir: File.dirname(@options[:i])
+  )
 
   after_fork(dir)
-
-  # create pid file
-  daemon_pid = File.new(@options[:i].to_s, 'w')
-  daemon_pid.sync = true
-  daemon_pid.puts(Process.pid.to_s)
-  daemon_pid.close
 end
 
 @clients = {}

spec/scripts/websocket_server_spec.rb

@@ -0,0 +1,39 @@
+require 'spec_helper'
+require 'timeout'
+
+describe 'websocket-server' do
+  # Why not Rails.root.join here?
+  # Because it's not avaialable in this spec (no 'rails_helper' = faster start-up)
+  let(:app_root)   { File.expand_path('../..', __dir__) }
+  let(:ws_server)  { File.expand_path('script/websocket-server.rb', app_root) }
+  let(:pidfile)    { File.expand_path('tmp/pids/websocket.pid', app_root) }
+  let(:output_log) { File.expand_path('log/websocket-server_out.log', app_root) }
+  let(:error_log)  { File.expand_path('log/websocket-server_err.log', app_root) }
+
+  context 'with IPv6 bind address (via -b option)' do
+    # This error is raised for invalid bind addresses
+    let(:error_msg) { "`start_tcp_server': no acceptor" }
+    let(:ipv6_addr) { '::1/128' }
+
+    # Flush logs
+    before do
+      File.write(output_log, '')
+      File.write(error_log, '')
+    end
+
+    it 'starts up successfully' do
+      begin
+        system("#{ws_server} start -db #{ipv6_addr} >/dev/null 2>&1")
+
+        # Wait for daemon to start
+        Timeout.timeout(20, Timeout::Error, 'WebSocket Server startup timed out') do
+          loop { break if File.size(output_log) + File.size(error_log) > 0 }
+        end
+
+        expect(File.read(error_log)).not_to include(error_msg)
+      ensure
+        system("#{ws_server} stop >/dev/null 2>&1") if File.exist?(pidfile)
+      end
+    end
+  end
+end