in_dstat_stdin.rb

module Fluent
  class DstatStdinInput < Input
    Plugin.register_input('dstat_stdin', self)

    def initialize
      super
    end

    config_param :tag, :string
    config_param :dstat_path, :string, :default => "dstat"
    config_param :option, :string
    config_param :delay, :integer, :default => 1
    config_param :hostname_command, :string, :default => "hostname"

    class TimerWatcher < Coolio::TimerWatcher
      def initialize(interval, repeat, &callback)
        @callback = callback
        super(interval, repeat)
      end

      def on_timer
        @callback.call
      rescue
        # TODO log?
        $log.error $!.to_s
        $log.error_backtrace
      end
    end

    def configure(conf)
      super
      @hostname = `#{@hostname_command}`.chomp!
    end

    def start
      @loop = Coolio::Loop.new
      @timer = TimerWatcher.new(@delay, true, &method(:on_timer))
      @loop.attach(@timer)
      @thread = Thread.new(&method(:run))
    end

    def shutdown
      @loop.watchers.each {|w| w.detach }
      @loop.stop
      @thread.join
    end

    def run
      @loop.run
    rescue
      $log.error "unexpected error", :error=>$!.to_s
      $log.error_backtrace
    end

    def on_timer
      command = "#{@dstat_path} #{@option} #{@delay} 1"
      now = Engine.now
      io = IO.popen(command, "r")
      lines = io.readlines()
      io.close
      headers1 = lines[0].gsub("\u001B[7l", "").split()
      headers2 = lines[1].split("|")
      datas = lines[3].split("|")
 
      data = Hash.new
      headers1.each_with_index{|header, i|
        child_headers = headers2[i].split()
        child_datas = datas[i].split()
        child_record = Hash.new
        child_headers.each_with_index{|cheader, j|
          child_record[cheader] = child_datas[j].to_f
        }
        data[strip_dash(header)] = child_record
      }
      record = {
        'hostname' => @hostname,
        'dstat' => data
      }
      Engine.emit(@tag, now, record)
    end

    def strip_dash(word)
      word.gsub("-", " ").split().join("-")
    end
  end
end