curator/src/lib/system/procPoller.coffee

A flexible process monitoring and management framework.

# This is the procfs poller.

fs = require 'fs'
os = require 'os'

kb_per_page = 4
hertz = 100

# Memory usage in KiB
mem = (stat) ->
  stat.rss * kb_per_page

# pmem and pcpu algorithms are from god-rb
pmem = (stat) ->
  stat.mem * 1024 / os.totalmem() * 100

pcpu = (stat) ->
   total_time = stat.utime + stat.stime
   seconds = stat.timestamp - stat.starttime / hertz
   (total_time * 1000 / hertz) / seconds / 10

# Interval pcpu, CPU utilization within some interval
ipcpu = exports.ipcpu = (old_utime, old_stime, interval, stat) ->
   total_time = stat.utime + stat.stime - old_utime - old_stime
   seconds = interval / 1000
   (total_time * 1000 / hertz) / seconds / 10

exports.poll = (pid, callback) ->
  fs.readFile "/proc/#{pid}/stat", (err, data) ->
    if err
      callback err, null
      return

    data = data.toString('ascii').split ' '

    stat =
      pid: parseInt(data[0]), comm: data[1], state: data[2],
      ppid: parseInt(data[3]), pgrp: parseInt(data[4]),
      session: parseInt(data[5]), tty_nr: parseInt(data[6]),
      tpgid: parseInt(data[7]), flags: parseInt(data[8]),
      minflt: parseInt(data[9]), cminflt: parseInt(data[10]),
      majflt: parseInt(data[11]), cmajflt: parseInt(data[12]),
      utime: parseInt(data[13]), stime: parseInt(data[14]),
      cutime: parseInt(data[15]), cstime: parseInt(data[16]),
      priority: parseInt(data[17]), nice: parseInt(data[18]),
      num_threads: parseInt(data[19]), itrealvalue: parseInt(data[20]),
      starttime: parseInt(data[21]), vsize: parseInt(data[22]),
      rss: parseInt(data[23]), rsslim: parseInt(data[24]),
      startcode: parseInt(data[25]), endcode: parseInt(data[26]),
      startstack: parseInt(data[27]), kstkesp: parseInt(data[28]),
      kstkeip: parseInt(data[29]), signal: parseInt(data[30]),
      blocked: parseInt(data[31]), sigignore: parseInt(data[32]),
      sigcatch: parseInt(data[33]), wchan: parseInt(data[34]),
      nswap: parseInt(data[35]), cnswap: parseInt(data[36]),
      exit_signal: parseInt(data[37]), processor: parseInt(data[38]),
      rt_priority: parseInt(data[39]), policy: parseInt(data[40]),
      delayacct_blkio_ticks: parseInt(data[41]), guest_time: parseInt(data[42]),
      cguest_time: parseInt data[43].trim()

    stat.timestamp = os.uptime()

    stat.mem = mem stat
    stat.pmem = pmem stat
    stat.pcpu = pcpu stat

    callback null, stat