From fd2709a6fa2c2cc764aa2b1a50178ad62e71a1c5 Mon Sep 17 00:00:00 2001
From: Wilfried Teiken <wteiken@google.com>
Date: Tue, 5 Jan 2016 23:58:23 -0500
Subject: [PATCH] Move dnspython dependency to tests only and only import the
 dns.resolver when actually resolving the client.  That way user code that
 does not call 'simple_verify' for DNS01 challenges does not depend on
 dnspython.

---
 acme/acme/challenges.py | 10 ++++++----
 acme/setup.py           |  3 +--
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/acme/acme/challenges.py b/acme/acme/challenges.py
index e235a087e..aa7b20689 100644
--- a/acme/acme/challenges.py
+++ b/acme/acme/challenges.py
@@ -6,8 +6,6 @@ import logging
 import socket
 
 from cryptography.hazmat.primitives import hashes
-import dns.resolver
-import dns.exception
 import OpenSSL
 import requests
 
@@ -714,8 +712,12 @@ def txt_records_for_name(name):
 
     """
     try:
+        import dns.resolver
         dns_response = dns.resolver.query(name, 'TXT')
-    except dns.exception.DNSException as error:
-        logger.error("Unable to resolve %s: %s", name, error)
+    except ImportError as error:
+        raise ImportError("Local validation for 'dns-01' challenges requires "
+                          "'dnspython'");
+    except Exception as error:
+        logger.error("Unable to resolve %s: %s", name, str(error))
         return []
     return [txt_rec for rdata in dns_response for txt_rec in rdata.strings]
diff --git a/acme/setup.py b/acme/setup.py
index dd2bce5d9..76a2c1b72 100644
--- a/acme/setup.py
+++ b/acme/setup.py
@@ -12,7 +12,6 @@ install_requires = [
     'cryptography>=0.8',
     # Connection.set_tlsext_host_name (>=0.13), X509Req.get_extensions (>=0.15)
     'PyOpenSSL>=0.15',
-    'dnspython',
     'pyrfc3339',
     'pytz',
     'requests',
@@ -76,7 +75,7 @@ setup(
     install_requires=install_requires,
     extras_require={
         'docs': docs_extras,
-        'testing': testing_extras,
+        'testing': testing_extras + 'dnspython',
     },
     entry_points={
         'console_scripts': [