check-pm2.rb

#! /usr/bin/env ruby
#
# Check PM2 
#
#
# DESCRIPTION:
#  Check check if all the processes managed by the PM2 manager are running.
#
# OUTPUT:
#   plain-text
#
# PLATFORMS:
#   all
#
# DEPENDENCIES:
#
# Add the following 3 lines into your sensu file in the /etc/sudorers.d/ folder
#
#   Defaults:sensu !requiretty
#   Defaults:sensu secure_path = /opt/sensu/embedded/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
# 
#   sensu   ALL=(ALL)NOPASSWD: ALL
#
# USAGE:
#   ./check-pm2.rb -u <username> [--status | -memory | -cpu ]] -w <seconds> -c <seconds>
#
# EXAMPLES:
#
#   ./check_pm2.rb -u my_user -w 1 -c 1 -s online 
#
#   If one process managed by PM2 are not in online state, it throws a critical.
#
#   ./check_pm2.rb -u my_user -w 1 -c 2 -m 60
#
#   If one process is consuming 60 MB or more then the check throws a warning.
#   If 2 o more process are consuming 60 MB or more, then it throws a critical.
#
# LICENSE: 
# Copyright Marcos Martínez <frommelmak@gmail.com>
#
# Released under the same terms as Sensu (the MIT license); see LICENSE
# for details.
#
require 'sensu-plugin/check/cli'
require 'json'

class CheckPM2 < Sensu::Plugin::Check::CLI
  option :critical,
    :description => "Max allowed value to consider critical",
    :short => '-c VALUE',
    :long => '--critical=VALUE',
    :proc => proc {|a| a.to_i },
    :required => true

  option :warning,
    :description => "Max allowed value to consider warning",
    :short => '-w VALUE',
    :long => '--warning=VALUE',
    :proc => proc {|a| a.to_i },
    :required => true

  option :username,
    :description => "The user running pm2",
    :short => '-u USER',
    :long => '--username=USER',
    :required => true

  option :status,
    :description => "Look for the status to throw alerts\n \
                     \t\t     Available status: online, stopping, stopped, launching, errored, one-launch-status",
    :short => '-s STATUS',
    :long => '--status=STATUS',
    :required => false

  option :memory,
    :description => "Look for the max amount of memory allowed for a process to throw alerts",
    :short => '-m MEM',
    :long => '--memory=MEM',
    :required => false

  option :cpu,
    :description => "Look for the % of CPU usage to throw alerts",
    :short => '-l LOAD',
    :long => '--load=LOAD',
    :required => false


  def run

    json = `sudo -iu #{config[:username]} pm2 jlist`
    processes_hash = JSON.parse(json)
    n = 0
    limit = 'none'

    if config[:warning] > config[:critical]
       puts "ERROR: Warning threshold can not be greater than Critical!"
       exit 1
    end

    bad_metric_counter =0
    processes_hash.each do |process|
      if config[:status]
        limit="not #{config[:status]}"
        if config[:status] != process["pm2_env"]["status"]
          bad_metric_counter += 1
        end
      elsif config[:memory]
        limit="memory > #{config[:memory]} MB"
        if process["monit"]["memory"].fdiv(1024*1024).round >= config[:memory].to_i
          bad_metric_counter += 1
        end
      elsif config[:load]
        limit="load > #{config[:cpu]} %"
        if process["monit"]["cpu"] >= config[:load].to_i
          bad_metric_counter += 1
        end

      end
    end
    msg = "There are #{bad_metric_counter} processes in bad status (#{limit})"
    critical msg if bad_metric_counter >= config[:critical]
    warning msg if bad_metric_counter >= config[:warning]
    ok msg
  end
end