fluent/fluentd

<source>
  @type sample
  @label @exec
  tag exec_input
  rate 10
  auto_increment_key num
  sample {"data":"mydata"}
</source>

<label @exec>
  <match exec_input>
    @type exec_filter
    @label @stdout
    tag result
    command ruby -e 'STDOUT.sync = true; proc = ->(){line = STDIN.readline.chomp; puts line + "\t" + Process.pid.to_s}; 1000.times{ proc.call }'
    num_children 3
    child_respawn -1
    <inject>
      time_key time
      time_type float
    </inject>
    <format>
      @type tsv
      keys data, num, time
    </format>
    <parse>
      @type tsv
      keys data, num, time, pid
    </parse>
    <extract>
      time_key time
      time_type float
    </extract>
  </match>
</label>

<label @stdout>
  <match result>
    @type stdout
  </match>
</label>