dnspython docker dns issue

docker-compose.yml

version: "2"
services:
  test-service:
    container_name: test-service
    image: busybox
    command: ['/bin/sh', '-c', 'sleep 5']

  test-client:
    container_name: test-client
    build: .
    dns_search: foo.example.com

Dockerfile

FROM python:3.4

RUN pip install dnspython

COPY test.py /var/tmp/test.py

CMD [ "python", "/var/tmp/test.py" ]

test.py

import dns.resolver
import socket

service_url = 'test-service'


print('### socket example ###')

ip_list = []
ais = socket.getaddrinfo(service_url, 0, 0, 0, 0)
for result in ais:
    ip_list.append(result[-1][0])
ip_list = list(set(ip_list))
print(ip_list[0])

print('### dnspython example ###')

resolver = dns.resolver.Resolver()
answers = resolver.query(service_url)
for data in answers:
    print(data.address)

Gist used for rthalley/dnspython#219