gistfile1.rb

#!/usr/bin/env ruby
# -*- coding: utf-8 -*-
#
# worker starter
# x process starter ?
# x process runner ?
# (元process-manager.pl)
#
# - 複数種類のworkerプロセスを複数まとめて起動する
# - configで指定するプロセスは任意のプログラム(rubyに限らない)
# - configに書かれたプロセスを起動後、一定時間毎に起動したプロセスチェックしていなくなってれば新たに起動する
# - なのでloopしないプロセスは再起動される
# - このスクリプトプロセス自体はdaemontoolsで管理するとdaemon化できていいと思います
# - プロセス管理自体はdaemontoolsで
#
# TODO:
# - god?
#
# 2009-11-24 koyachi
require 'rubygems'
require 'yaml'
require 'thread'
require 'logger'

HELP = <<HELP
USAGE

  $ ruby process_manager.rb /path/to/your/config.yaml

CONFIG SAMPLE

#-- config.yaml --
worker_process:
  - name: foo
    cmd: 'echo "hello"'
    num: 2
  - name: foo
    cmd: 'echo "hello 2"'
    num: 3
  - name: foo
    cmd: 'ruby -e "loop {p \"loop!\"; sleep 2}"'
    num: 3

HELP
config_file = ARGV[0] || abort("\n#{HELP}")

# managerっていうかstarter/runnerか
# まとめて開始する、的な言葉
module ProcessManager
  class << self
    $protect_from_signals_mutex = Mutex.new
    def protect_from_signals
      $protect_from_signals_mutex.synchronize do
        interrupted = false
        previous_handler = Signal.trap(:INT) {interrupted = true}
        yield
        Signal.trap(:INT, previous_handler)
        # ガード中に割り込み受けたらガード対象処理終わってからハンドラを起動する
        previous_handler.call if interrupted
      end
    end

    def _huntsman
      Signal.trap :CHLD, 'IGNORE'
      ProcessManager.active.keys.each {|pid| Process.kill 'INT', pid}
      exit
    end

    def _hup
      Signal.trap :CHLD, 'IGNORE'
      ProcessManager.active.keys.each {|pid| Process.kill 'HUP', pid}
    end

    attr_accessor :active, :logger
    def init(config_file)
      @logger = Logger.new(STDOUT)
      @logger.level = Logger::WARN
      @logger.info "start process runner: [#{$$}]"
      @active = {}
      config = YAML.load_file(config_file)
      @logger.info config
      config['worker_process'].each do |process|
        process['num'].times {start_process process}
      end
    end

    def start_process(process)
      protect_from_signals do
        pid = fork
        if pid
          # parent process
          @logger.info "start: [#{pid}] #{process['name']}"
          @active[pid] = process
        else
          # child process
          exec process['cmd']
          exit
        end
      end
    end

    def run(config_file)
      Signal.trap(:INT) {self._huntsman}
      Signal.trap(:TERM) {self._huntsman}
      Signal.trap(:HUP) {self._hup}
      self.init config_file

      loop do
        @logger.debug "active processes: [#{@active.keys.sort.join(",")}]"
        sleep 10
        @active.keys.each do |pid|
          _pid = Process.waitpid pid, Process::WNOHANG
          if _pid
            @logger.info "process has gone. restart: [#{pid}] #{@active[pid]['name']}"
            process = @active.delete pid
            start_process process
          end
        end
      end
    end
  end
end

ProcessManager.run(config_file)