#!/usr/bin/env python2.7 # Copyright 2015 gRPC authors. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Makes DNS queries for A records to specified servers""" import argparse import signal import twisted.internet.task as task import twisted.names.client as client def main(): argp = argparse.ArgumentParser(description='Make DNS queries for A records') argp.add_argument('-s', '--server_host', default='127.0.0.1', type=str, help='Host for DNS server to listen on for TCP and UDP.') argp.add_argument('-p', '--server_port', default=53, type=int, help='Port that the DNS server is listening on.') argp.add_argument('-n', '--qname', default=None, type=str, help=('Name of the record to query for. ')) argp.add_argument('-t', '--timeout', default=1, type=int, help=('Force process exit after this number of seconds.')) args = argp.parse_args() signal.alarm(args.timeout) def OnResolverResultAvailable(result): answers, authority, additional = result for a in answers: print(a.payload) def BeginQuery(reactor, qname): servers = [(args.server_host, args.server_port)] resolver = client.Resolver(servers=servers) deferred_result = resolver.lookupAddress(args.qname) deferred_result.addCallback(OnResolverResultAvailable) return deferred_result task.react(BeginQuery, [args.qname]) if __name__ == '__main__': main()