Add ability to restart by reexecing and pumactl to use it

This allows all existing requests to finish, but does not keep the same
socket alive across the exec, so this is not a graceful as it could be.

bin/puma

@@ -10,6 +10,7 @@ cli = Puma::CLI.new ARGV
 begin
   cli.run
 rescue => e
+  raise e if $DEBUG
   STDERR.puts e.message
   exit 1
 end

bin/pumactl

@@ -0,0 +1,12 @@
+#!/usr/bin/env ruby
+
+require 'puma/control_cli'
+
+cli = Puma::ControlCLI.new ARGV
+
+begin
+  cli.run
+rescue => e
+  STDERR.puts e.message
+  exit 1
+end

lib/puma/app/status.rb

@@ -1,8 +1,9 @@
 module Puma
   module App
     class Status
-      def initialize(server)
+      def initialize(server, cli)
         @server = server
+        @cli = cli
       end
 
       def call(env)
@@ -15,6 +16,14 @@ def call(env)
           @server.halt
           return [200, {}, ['{ "status": "ok" }']]
 
+        when "/restart"
+          if @cli and @cli.restart_on_stop!
+            @server.stop
+            return [200, {}, ['{ "status": "ok" }']]
+          else
+            return [200, {}, ['{ "status": "not configured" }']]
+          end
+
         when "/stats"
           b = @server.backlog
           r = @server.running

lib/puma/cli.rb

@@ -31,7 +31,58 @@ def initialize(argv, stdout=STDOUT, stderr=STDERR)
       @server = nil
       @status = nil
 
+      @restart = false
+      @temp_status_path = nil
+
       setup_options
+
+      generate_restart_data
+    end
+
+    def restart_on_stop!
+      if @restart_argv
+        @restart = true
+        return true
+      else
+        return false
+      end
+    end
+
+    def generate_restart_data
+      # Use the same trick as unicorn, namely favor PWD because
+      # it will contain an unresolved symlink, useful for when
+      # the pwd is /data/releases/current.
+      if dir = ENV['PWD']
+        s_env = File.stat(dir)
+        s_pwd = File.stat(Dir.pwd)
+
+        if s_env.ino == s_pwd.ino and s_env.dev == s_pwd.dev
+          @restart_dir = dir
+        end
+      end
+
+      @restart_dir ||= Dir.pwd
+
+      if defined? Rubinius::OS_ARGV
+        @restart_argv = Rubinius::OS_ARGV
+      else
+        require 'rubygems'
+
+        # if $0 is a file in the current directory, then restart
+        # it the same, otherwise add -S on there because it was
+        # picked up in PATH.
+        #
+        if File.exists?($0)
+          @restart_argv = [Gem.ruby, $0] + ARGV
+        else
+          @restart_argv = [Gem.ruby, "-S", $0] + ARGV
+        end
+      end
+    end
+
+    def restart!
+      Dir.chdir @restart_dir
+      Kernel.exec(*@restart_argv)
     end
 
     # Write +str+ to +@stdout+
@@ -87,7 +138,7 @@ def setup_options
         end
 
         o.on "--status [URL]", "The bind url to use for the status server" do |arg|
-          if arg
+          if arg and arg != "@"
             @options[:status_address] = arg
           elsif IS_JRUBY
             raise NotImplementedError, "No default url available on JRuby"
@@ -97,6 +148,8 @@ def setup_options
             t = (Time.now.to_f * 1000).to_i
             path = "#{Dir.tmpdir}/puma-status-#{t}-#{$$}"
 
+            @temp_status_path = path
+
             @options[:status_address] = "unix://#{path}"
           end
         end
@@ -171,6 +224,7 @@ def run
 
       load_rackup
       write_pid
+      write_state
 
       unless @options[:quiet]
         @app = Rack::CommonLogger.new(@app, STDOUT)
@@ -219,7 +273,7 @@ def run
 
         uri = URI.parse str
 
-        app = Puma::App::Status.new server
+        app = Puma::App::Status.new server, self
         status = Puma::Server.new app, @events
         status.min_threads = 0
         status.max_threads = 1
@@ -250,6 +304,13 @@ def run
         server.stop(true)
         log " - Goodbye!"
       end
+
+      File.unlink @temp_status_path if @temp_status_path
+
+      if @restart
+        log "* Restarting..."
+        restart!
+      end
     end
 
     def stop

lib/puma/control_cli.rb

@@ -0,0 +1,112 @@
+require 'optparse'
+
+require 'puma/const'
+require 'yaml'
+require 'uri'
+
+require 'socket'
+
+module Puma
+  class ControlCLI
+
+    def initialize(argv)
+      @argv = argv
+    end
+
+    def setup_options
+      @parser = OptionParser.new do |o|
+        o.on "-S", "--state PATH", "Where the state file to use is" do |arg|
+          @path = arg
+        end
+      end
+    end
+
+    def connect
+      if str = @state['status_address']
+        uri = URI.parse str
+        case uri.scheme
+        when "tcp"
+          return TCPSocket.new uri.host, uri.port
+        when "unix"
+          path = "#{uri.host}#{uri.path}"
+          return UNIXSocket.new path
+        else
+          raise "Invalid URI: #{str}"
+        end
+      end
+
+      raise "No status address configured"
+    end
+
+    def run
+      setup_options
+
+      @parser.parse! @argv
+
+      @state = YAML.load_file(@path)
+
+      cmd = @argv.shift
+
+      meth = "command_#{cmd}"
+
+      if respond_to?(meth)
+        __send__(meth)
+      else
+        raise "Unknown command: #{cmd}"
+      end
+    end
+
+    def command_pid
+      puts "#{@state['pid']}"
+    end
+
+    def command_stop
+      sock = connect
+      sock << "GET /stop HTTP/1.0\r\n\r\n"
+      rep = sock.read
+
+      body = rep.split("\r\n").last
+      if body != '{ "status": "ok" }'
+        raise "Invalid response: '#{body}'"
+      else
+        puts "Requested stop from server"
+      end
+    end
+
+    def command_halt
+      sock = connect
+      s << "GET /halt HTTP/1.0\r\n\r\n"
+      rep = s.read
+
+      body = rep.split("\r\n").last
+      if body != '{ "status": "ok" }'
+        raise "Invalid response: '#{body}'"
+      else
+        puts "Requested halt from server"
+      end
+    end
+
+    def command_restart
+      sock = connect
+      sock << "GET /restart HTTP/1.0\r\n\r\n"
+      rep = sock.read
+
+      body = rep.split("\r\n").last
+      if body != '{ "status": "ok" }'
+        raise "Invalid response: '#{body}'"
+      else
+        puts "Requested restart from server"
+      end
+    end
+
+    def command_stats
+      sock = connect
+      s << "GET /stats HTTP/1.0\r\n\r\n"
+      rep = s.read
+
+      body = rep.split("\r\n").last
+
+      puts body
+    end
+  end
+end

test/test_app_status.rb

@@ -23,7 +23,7 @@ def halt
 
   def setup
     @server = FakeServer.new
-    @app = Puma::App::Status.new(@server)
+    @app = Puma::App::Status.new(@server, @server)
   end
 
   def test_unsupported