Disable eventlet monkey-patching of DNS

This change avoids eventlet's monkey-patching of DNS
resolution. eventlet's doesn't support IPv6, for example.

The way to avoid eventlet's DNS is to set an environment
variable. The trick is the environment variable needs to be set
before eventlet is imported.

A similar change was made in nova, so this is just copying
that code and technique to keystone.

This allows re-enabling the IPv6 tests, too.

Change-Id: I30524a1cebd43580d692fd88ef32be45e62758c5

bin/keystone-all

@@ -2,12 +2,25 @@
 # vim: tabstop=4 shiftwidth=4 softtabstop=4
 
 import greenlet
-import eventlet
 import logging
 import os
 import signal
 import sys
 
+# NOTE(mikal): All of this is because if dnspython is present in your
+# environment then eventlet monkeypatches socket.getaddrinfo() with an
+# implementation which doesn't work for IPv6. What we're checking here is
+# that the magic environment variable was set when the import happened.
+if ('eventlet' in sys.modules and
+        os.environ.get('EVENTLET_NO_GREENDNS', '').lower() != 'yes'):
+    raise ImportError('eventlet imported before keystone-all '
+                      '(env var set to %s)'
+                      % os.environ.get('EVENTLET_NO_GREENDNS'))
+
+os.environ['EVENTLET_NO_GREENDNS'] = 'yes'
+
+import eventlet
+
 # If ../keystone/__init__.py exists, add ../ to Python search path, so that
 # it will override what happens to be installed in /usr/(local/)lib/python...
 possible_topdir = os.path.normpath(os.path.join(os.path.abspath(__file__),

keystone/__init__.py

@@ -0,0 +1,15 @@
+
+import os
+import sys
+
+# NOTE(mikal): All of this is because if dnspython is present in your
+# environment then eventlet monkeypatches socket.getaddrinfo() with an
+# implementation which doesn't work for IPv6. What we're checking here is
+# that the magic environment variable was set when the import happened.
+if ('eventlet' in sys.modules and os.environ.get(
+        'EVENTLET_NO_GREENDNS', '').lower() != 'yes'):
+    raise ImportError('eventlet imported before keystone '
+                      '(env var set to %s)'
+                      % os.environ.get('EVENTLET_NO_GREENDNS'))
+
+os.environ['EVENTLET_NO_GREENDNS'] = 'yes'

keystone/test.py

@@ -14,12 +14,14 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+
+import os
+import sys
+
 import datetime
 import errno
-import os
 import socket
 import subprocess
-import sys
 import time
 
 import eventlet
@@ -351,10 +353,6 @@ class TestCase(NoModule, unittest.TestCase):
     @staticmethod
     def skip_if_no_ipv6():
 
-        # TODO(blk-u): lp 1176204. At this time, eventlet address resolution
-        # doesn't support IPv6. Once it does, remove the next line.
-        raise nose.exc.SkipTest("Eventlet doesn't support IPv6, lp 1176204")
-
         try:
             s = socket.socket(socket.AF_INET6)
         except socket.error as e: