Extensions can now modify resources.

Change-Id: I0d9c1050428d0ccf2e2b18053d75e0465463c08b

1 files changed, 39 insertions, 0 deletions

diff --git a/novaclient/extension.py b/novaclient/extension.py
new file mode 100644
index 00000000..7c91a8e8
--- /dev/null
+++ b/novaclient/extension.py
@@ -0,0 +1,39 @@
+# Copyright 2011 OpenStack LLC.
+# All Rights Reserved.
+#
+#    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.
+
+from novaclient import base
+from novaclient import utils
+
+
+class Extension(utils.HookableMixin):
+    """Extension descriptor."""
+
+    SUPPORTED_HOOKS = ('__pre_parse_args__', '__post_parse_args__')
+
+    def __init__(self, name, module):
+        self.name = name
+        self.module = module
+        self._parse_extension_module()
+
+    def _parse_extension_module(self):
+        self.manager_class = None
+        for attr_name, attr_value in self.module.__dict__.items():
+            if attr_name in self.SUPPORTED_HOOKS:
+                self.add_hook(attr_name, attr_value)
+            elif utils.safe_issubclass(attr_value, base.Manager):
+                self.manager_class = attr_value
+
+    def __repr__(self):
+        return "<Extension '%s'>" % self.name