resolver.rb

require 'json'
require 'dnsruby'
include Dnsruby

REC_TYPES = %w(A AAAA NS CNAME MX PTR TXT SOA SPF)
DEA_HOSTS = File.open('hosts.csv', 'r')
RESOLVER  = Resolver.new

TMP_STORE = {}

def fetch_record(host, type)
  result = RESOLVER.query(host, type)
  { type => result.answer.map(&:to_s) }
end

DEA_HOSTS.each_line do |line|
  host = line.strip
  records = REC_TYPES.map{ |type| fetch_record(host, type) }
  TMP_STORE[host] = records
  rescue => e
    puts "#{host}: #{e.message}"
end

File.open('output.json', 'w') do |io|
  io << JSON.pretty_generate(TMP_STORE)
end