1 files changed, 100 insertions, 0 deletions
diff --git a/keystone-moon/keystone/common/environment/__init__.py b/keystone-moon/keystone/common/environment/__init__.py
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+++ b/keystone-moon/keystone/common/environment/__init__.py
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+# Copyright 2013 OpenStack Foundation
+#
+#    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.
+
+import functools
+import os
+
+from oslo_log import log
+
+LOG = log.getLogger(__name__)
+
+
+__all__ = ['Server', 'httplib', 'subprocess']
+
+_configured = False
+
+Server = None
+httplib = None
+subprocess = None
+
+
+def configure_once(name):
+    """Ensure that environment configuration is only run once.
+
+    If environment is reconfigured in the same way then it is ignored.
+    It is an error to attempt to reconfigure environment in a different way.
+    """
+    def decorator(func):
+        @functools.wraps(func)
+        def wrapper(*args, **kwargs):
+            global _configured
+            if _configured:
+                if _configured == name:
+                    return
+                else:
+                    raise SystemError("Environment has already been "
+                                      "configured as %s" % _configured)
+
+            LOG.debug("Environment configured as: %s", name)
+            _configured = name
+            return func(*args, **kwargs)
+
+        return wrapper
+    return decorator
+
+
+@configure_once('eventlet')
+def use_eventlet(monkeypatch_thread=None):
+    global httplib, subprocess, Server
+
+    # This must be set before the initial import of eventlet because if
+    # dnspython is present in your environment then eventlet monkeypatches
+    # socket.getaddrinfo() with an implementation which doesn't work for IPv6.
+    os.environ['EVENTLET_NO_GREENDNS'] = 'yes'
+
+    import eventlet
+    from eventlet.green import httplib as _httplib
+    from eventlet.green import subprocess as _subprocess
+
+    from keystone.common.environment import eventlet_server
+
+    if monkeypatch_thread is None:
+        monkeypatch_thread = not os.getenv('STANDARD_THREADS')
+
+    # Raise the default from 8192 to accommodate large tokens
+    eventlet.wsgi.MAX_HEADER_LINE = 16384
+
+    # NOTE(ldbragst): Explicitly declare what should be monkey patched and
+    # what shouldn't. Doing this allows for more readable code when
+    # understanding Eventlet in Keystone. The following is a complete list
+    # of what is monkey patched instead of passing all=False and then passing
+    # module=True to monkey patch a specific module.
+    eventlet.patcher.monkey_patch(os=False, select=True, socket=True,
+                                  thread=monkeypatch_thread, time=True,
+                                  psycopg=False, MySQLdb=False)
+
+    Server = eventlet_server.Server
+    httplib = _httplib
+    subprocess = _subprocess
+
+
+@configure_once('stdlib')
+def use_stdlib():
+    global httplib, subprocess
+
+    import httplib as _httplib
+    import subprocess as _subprocess
+
+    httplib = _httplib
+    subprocess = _subprocess