Nagios plugin to monitor delayed job active record queue

check_dj.rb

#!/usr/bin/env ruby
# encoding: utf-8

#
# Nagios plugin to monitor delayed job active record queue
#

# will use mysql2 gem
# --dsn mysql2://root@localhost/portal_development
#

# Nagios plugin exit codes
# 0 - ok
# 1 - warn
# 2 - critical
# 3 - unknown

require 'optparse'
require 'optparse/time'
require 'ostruct'
require 'logger'
require 'rubygems'
require 'sequel'

class CliArguments
  attr_reader :opts

  #
  # Return a structure describing the options.
  #
  def parse(args)
    # The options specified on the command line will be collected in *options*.
    # We set default values here.
    options = OpenStruct.new
    options.warning  = 10
    options.critical = 20
    options.verbose  = false

    @opts = opts = OptionParser.new do |opts|
      opts.banner = "Usage: #{__FILE__} [options]"

      opts.separator ""
      opts.separator "Specific options:"

      opts.on('-w', '--warning N', 'Number of jobs for warning code') { |n| options.warning = n.to_i }
      opts.on('-c', '--critical N', 'Number of jobs for critical code') { |n| options.critical = n.to_i }
      opts.on('-d', '--dsn DSN', 'Sequel datasource name: mysql://user:pass@host:port/database_name') { |dsn| options.dsn = dsn }

      # No argument, shows at tail.  This will print an options summary.
      opts.on_tail("-h", "--help", "Show this message") do
        puts opts
        exit
      end
    end

    opts.parse!(args)
    options
  end # parse()

end # class CliArguments
#

if __FILE__ == $0
  options = (parser = CliArguments.new).parse(ARGV)

  #p options
  if options.dsn.nil?
    puts parser.opts
    exit 1
  end

  begin
  db = Sequel.connect(options.dsn, encoding: 'utf8')
  row = db['select count(*) as count from delayed_jobs'].first
  puts row[:count]

  if row[:count] >= options.critical
    exit 2
  elsif row[:count] >= options.warning
    exit 1
  end

  rescue => e
    puts e.message
    exit 3
  end
end