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

1 files changed, 14 insertions, 1 deletions

diff --git a/bin/keystone-all b/bin/keystone-all
index 2fdc8c7a..64c6342b 100755
--- a/bin/keystone-all
+++ b/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__),