Ruby DNS TTL

ruby_dns_ttl.rb

def get_ip(hostname)
  dns = Resolv.new
  redis = Redis.new # storing in redis
  ip = redis.get("ip:#{hostname}") 
  return ip unless ip.nil?
  begin
    resource = dns.getresource(hostname, Resolv::DNS::Resource::IN::A)
  rescue Resolv::ResolvError
    return false
  end
  # storing in redis for only as long as the TTL allows
  redis.setex("ip:#{hostname}", resource.address.ttl, resource.address.to_s)
  resource.address.to_s # IP address as string
end