warm-slave.rb

#! /usr/bin/env ruby

$: << '/ops/lib/ruby'

TARGET_HOST=''
TARGET_USER=''
TARGET_PASS=''
TARGET_DB=''

require 'rubygems'
require 'pcaplet'
require 'mysql'

MYSQL_COM_QUERY = 0x03

target_db = Mysql.real_connect(TARGET_HOST, TARGET_USER, TARGET_PASS, TARGET_DB)

mysqlsniff = Pcaplet.new('-s 65535 -i eth0')
mysqlsniff.add_filter Pcap::Filter.new("tcp port 3306 and not dst #{TARGET_HOST}",
                                       mysqlsniff.capture)
query = ''
query_length = 0

mysqlsniff.each_packet do |pkt|
  next unless pkt.tcp_data
  if query then
    if query.length == query_length then
      if query[/^select/i] then
        start_time = Time.now
        puts query
        target_db.query query
        times = "== [%.2fs] ==" % (Time.now - start_time)
        puts times + '=' * (80 - times.length)
        puts
      end
      query = nil
      query_length = 0
    else
      query << pkt.tcp_data
    end
  end

  if pkt.tcp_data[3] == 0 and pkt.tcp_data[4] == MYSQL_COM_QUERY then
    query_length = (pkt.tcp_data[0,3] + "\0").unpack('V')[0] - 1
    next if query_length < 1
    query = pkt.tcp_data[5..-1]
  end
end