ドメインとELBのIPアドレスを毎秒表示するRubyスクリプト。Route53でALIASでELBのドメインを設定した時用。domainとelb_domainの値を書き換えて使ってください。

dig_domain_and_elb.rb

#!/usr/bin/env ruby
# (c) 2014 Hioraki Nakamura
# MIT License
domain = "_YOUR_DOMAIN_HERE_"
elb_domain = "_YOUR_ELB_HOSTNAME_HERE_.ap-northeast-1.elb.amazonaws.com"

def get_ttl_and_ip(domain)
  ttl_and_ips = []
  IO.popen(["dig", domain], "r") do |io|
    while line = io.gets
      if line =~ /ANSWER SECTION/
        while (line = io.gets) != "\n"
          words = line.split(/\s+/)
          ttl_and_ips << {ttl: words[1], ip: words[4]}
        end
        break
      end
    end
  end
  ttl_and_ips
end

while true
  terms = []

  now = Time.now
  terms << "time:#{now.strftime("%Y-%m-%dT%H:%M:%S%z")}"

  ttl_and_ip = get_ttl_and_ip(domain)[0]
  terms << "ttl:#{ttl_and_ip[:ttl]}"
  terms << "ip:#{ttl_and_ip[:ip]}"

  elb_ttl_and_ips = get_ttl_and_ip elb_domain
  elb_ttl_and_ips.each_with_index do |ttl_and_ip, i|
    terms << "elb_ttl#{i}:#{ttl_and_ip[:ttl]}"
    terms << "elb_ip#{i}:#{ttl_and_ip[:ip]}"
  end

  puts terms.join("\t")

  sleep 1
end