Initialization of versioned objects

This patch starts the work on versioned objects. The versioned objects
will server two use cases: 1) an indirection layer for the database that
lays the foundation for live upgrade in future; 2) an abstraction of
objects that can be pumped to message queue (or other channels) or
persisted into database, aka. the notification interface.

Change-Id: I2040b1cdfbe4821cdab517ed14f116e1b0f8fdc5

requirements.txt

@@ -18,6 +18,7 @@ oslo.policy>=0.5.0 # Apache-2.0
 oslo.serialization>=1.10.0 # Apache-2.0
 oslo.service>=1.10.0 # Apache-2.0
 oslo.utils>=3.5.0 # Apache-2.0
+oslo.versionedobjects>=1.5.0,!=1.9.0 # Apache-2.0
 PasteDeploy>=1.5.0 # MIT
 pytz>=2013.6 # MIT
 PyYAML>=3.1.0 # MIT

senlin/objects/base.py

@@ -0,0 +1,28 @@
+# 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.
+
+"""Senlin common internal object model"""
+
+from oslo_versionedobjects import base
+
+
+class SenlinObject(base.VersionedObject):
+    """Base class for senlin objects.
+
+    This is the base class for all objects that can be remoted or instantiated
+    via RPC. Simply defining a sub-class of this class would make it remotely
+    instantiatable. Objects should implement the "get" class method and the
+    "save" object method.
+    """
+
+    OBJ_PROJECT_NAMESPACE = 'senlin'
+    VERSION = '1.0'

senlin/tests/unit/objects/test_base.py

@@ -0,0 +1,24 @@
+# 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 senlin.objects import base as obj_base
+from senlin.tests.unit.common import base
+
+
+class TestBaseObject(base.SenlinTestCase):
+
+    def test_base_class(self):
+        obj = obj_base.SenlinObject()
+        self.assertEqual(obj_base.SenlinObject.OBJ_PROJECT_NAMESPACE,
+                         obj.OBJ_PROJECT_NAMESPACE)
+        self.assertEqual(obj_base.SenlinObject.VERSION,
+                         obj.VERSION)