simple network monitor with ping and growl

ping_and_growl.rb

#! /usr/bin/env ruby
# -*- coding: utf-8 -*-

require 'logger'

=begin

WHATIS

 * ping monitoring once every 30 secs
 * growl and log if network is down

REQUIREMENT

 * ruby :)
 * ping
 * which
 * growl ( supplied with ruby-growl gem ) or growlnotify ( supplied with Growl )

GETTING STARTED

 configure

 @ip_base         your network segment
 @ipaddrs         host => addr Hash
 @growl_listener  your machine's ip addr

 $ ./ping_and_growl.rb &
 $ tail -f ping_monitor.log

=end

def main
  init()

  log = Logger.new( @logfile )
  log.level = Logger::INFO
  
  @ipaddrs.each_pair { |name, ip|
    Thread.new( log, name, ip ) {
      while true
        if ( !ping( ip ) )
          growl( name )
          log.warn( "#{name} きれてる！" )
        end
        sleep 30
      end
    }
  }
  sleep
end

def time
  Time.now.strftime( '%H:%M:%S' )
end

def ping( ip )
  system( "ping -c 1 #{@ip_base}.#{ip} > /dev/null" )
end

def growl( name )
  system( "#{@growl} -s -H #{@growl_listener} -m '#{time()} #{name} きれてる！'" )
end

def init
  @logfile = File.join( File.dirname( __FILE__ ), 'ping_monitor.log' )
  cmds     = %w(
                 growl
                 growlnotify
               )
  @growl   = Hash[*cmds.zip( cmds.map { |e|
                               `which #{e}`.chomp
                             } ).flatten
                 ].find { |k, v|
    v.size > 0
  }.last

  @ip_base = '192.168.1'
  @ipaddrs = {
    'foo' => 1,
    'bar' => 2,
    'baz' => 3
  }

  @growl_listener = xxx.xxx.xxx.xxx
end

main()