Removes created_at, updated_at from ModelBase

Created a 'TimestampMixin' class.
Next step is to update Nova which is the only project using oslo.db

Fixes bug #1119702

Change-Id: I1ffcc09a2971e6e6102da7ecb855a2837a159baf

openstack/common/db/sqlalchemy/models.py

@@ -33,8 +33,6 @@ from openstack.common import timeutils
 class ModelBase(object):
     """Base class for models."""
     __table_initialized__ = False
-    created_at = Column(DateTime, default=timeutils.utcnow)
-    updated_at = Column(DateTime, onupdate=timeutils.utcnow)
     metadata = None
 
     def save(self, session=None):
@@ -92,6 +90,11 @@ class ModelBase(object):
         return local.iteritems()
 
 
+class TimestampMixin(object):
+    created_at = Column(DateTime, default=timeutils.utcnow)
+    updated_at = Column(DateTime, onupdate=timeutils.utcnow)
+
+
 class SoftDeleteMixin(object):
     deleted_at = Column(DateTime)
     deleted = Column(Integer, default=0)

tests/unit/db/sqlalchemy/test_models.py

@@ -28,6 +28,7 @@ class ModelBaseTest(test_utils.BaseTestCase):
                         'get',
                         'next',
                         'update',
+                        'save',
                         'iteritems')
         for method in dict_methods:
             self.assertTrue(hasattr(models.ModelBase, method))
@@ -70,3 +71,24 @@ class ModelBaseTest(test_utils.BaseTestCase):
             found_items += 1
 
         self.assertEqual(min_items, found_items)
+
+
+class TimestampMixinTest(test_utils.BaseTestCase):
+
+    def test_timestampmixin_attr(self):
+
+        class TestModel(models.ModelBase, models.TimestampMixin):
+            pass
+
+        dict_methods = ('__getitem__',
+                        '__setitem__',
+                        '__iter__',
+                        'get',
+                        'next',
+                        'update',
+                        'save',
+                        'iteritems',
+                        'created_at',
+                        'updated_at')
+        for method in dict_methods:
+            self.assertTrue(hasattr(TestModel, method))