Class: Murakumo::HealthChecker

Inherits:
Object
  • Object
show all
Defined in:
lib/srv/murakumo_health_checker.rb

Instance Method Summary collapse

Constructor Details

#initialize(address, name, cloud, logger, options) ⇒ HealthChecker

Returns a new instance of HealthChecker.



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# File 'lib/srv/murakumo_health_checker.rb', line 13

def initialize(address, name, cloud, logger, options)
  @address = address
  @name = name
  @cloud = cloud
  @logger = logger
  @options = options

  # 各種変数の設定
  ['interval', 'timeout', 'healthy', 'unhealthy'].each {|key|
    value = options[key]
    instance_variable_set("@#{key}", value)
  }

  # スクリプトの読み込み
  @script = options['script']
  raise "health check script of #{@name} is not found" unless @script
  @script = File.read(@script) if File.exists?(@script)

  # 通知オブジェクトの設定
  if options[:notification]
    @notifier = HealthCheckNotifier.new(@address, @name, @logger, options[:notification])
  end

  # イベントハンドラの設定
  @on_activate = options['on-activate']
  @on_inactivate = options['on-inactivate']
end

Instance Method Details

#alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/srv/murakumo_health_checker.rb', line 143

def alive?
  @alive
end

#bad ⇒ Object 



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# File 'lib/srv/murakumo_health_checker.rb', line 49

def bad
  if not @normal_health
    @healthy_count = 0
  elsif (@unhealthy_count += 1) >= @unhealthy
    toggle_health
  end
end

#good ⇒ Object 



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# File 'lib/srv/murakumo_health_checker.rb', line 41

def good
  if @normal_health
    @unhealthy_count = 0
  elsif (@healthy_count += 1) >= @healthy
    toggle_health
  end
end

#start ⇒ Object 



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# File 'lib/srv/murakumo_health_checker.rb', line 89

def start
  # 各種変数は初期状態にする
  @alive = true
  @normal_health = (@options['init-status'] == ACTIVE)
  @healthy_count = 0
  @unhealthy_count = 0

  # 既存のスレッドは破棄
  if @thread and @thread.alive?
    begin
      @thread.kill
    rescue ThreadError
    end
  end

  @thread = Thread.start {
    begin
      while @alive
        retval = nil

        begin
          retval = timeout(@timeout) {
            HealthCheckContext.new(:name => @name, :logger => @logger, :options => @options).instance_eval(@script)
          }
        rescue Timeout::Error
          retval = false
        rescue => e
          retval = false
          message = (["#{e.class}: #{e.message}"] + (e.backtrace || [])).join("\n\tfrom ")
          @logger.error("health check failed: #{@name}: #{message}")
        end

        status = retval == true ? 'good' : retval == false ? 'bad' : '-'
        @logger.debug("result of a health check: #{@name}: #{status}")

        if retval == true
          good
        elsif retval == false
          bad
        end

        sleep @interval
      end # while
    rescue Exception => e
      message = (["#{e.class}: #{e.message}"] + (e.backtrace || [])).join("\n\tfrom ")
      @logger.error("#{@name}: #{message}")
    end # begin
  }
end

#stop ⇒ Object 



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# File 'lib/srv/murakumo_health_checker.rb', line 139

def stop
  @alive = false
end

#toggle_health ⇒ Object 



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# File 'lib/srv/murakumo_health_checker.rb', line 57

def toggle_health
  @normal_health = !@normal_health
  activity = (@normal_health ? ACTIVE : INACTIVE)

  @cloud.gossip.transaction do
    @cloud.gossip.data.each do |i|
      # 名前の一致するデータを更新
      i[4] = activity if i[0] == @name
    end
  end

  @cloud.db.execute(<<-EOS, activity, @cloud.address, @name)
    UPDATE records SET activity = ?
    WHERE ip_address = ? AND name = ?
  EOS

  @healthy_count = 0
  @unhealthy_count = 0

  status = @normal_health ? 'healthy' : 'unhealthy'
  @logger.info("health condition changed: #{@name}: #{status}")

  case activity
  when ACTIVE
    @notifier.notify_active if @notifier
    handle_event(@on_activate, 'healthy') if @on_activate
  when INACTIVE
    @notifier.notify_inactive if @notifier
    handle_event(@on_inactivate, 'unhealthy') if @on_inactivate
  end
end