Add VersionedObjectPrintable mixin

Added VersionedObjectPrintable mixin for versioned objects. If an
OVO inherits from this class, the output string will contain all
data stored in the object, along with the version, name, namespace
and fields changed.

Change-Id: Ice9418fc28ded9aff902a9e65008d68cb64093f5

os_vif/objects/base.py

@@ -16,3 +16,16 @@ from oslo_versionedobjects import base as ovo_base
 class VersionedObject(ovo_base.VersionedObject):
 
     OBJ_PROJECT_NAMESPACE = 'os_vif'
+
+
+class VersionedObjectPrintableMixin(object):
+    """Mix-in to implement __str__ method for a versioned object
+
+    If a versioned object needs to be printable in a easy-reading format,
+    inherit from this class.
+    """
+
+    def __str__(self):
+        if callable(getattr(self, 'obj_to_primitive', None)):
+            return str(self.obj_to_primitive())
+        return super(VersionedObjectPrintableMixin, self).__str__()

os_vif/objects/host_info.py

@@ -44,7 +44,8 @@ def _get_common_version(object_name, max_version, min_version, exc_notmatch,
 
 @base.VersionedObjectRegistry.register
 class HostPortProfileInfo(osv_base.VersionedObject,
-                          base.ComparableVersionedObject):
+                          base.ComparableVersionedObject,
+                          osv_base.VersionedObjectPrintableMixin):
     """
     Class describing a PortProfile class and its supported versions
     """
@@ -73,7 +74,8 @@ class HostPortProfileInfo(osv_base.VersionedObject,
 
 
 @base.VersionedObjectRegistry.register
-class HostVIFInfo(osv_base.VersionedObject, base.ComparableVersionedObject):
+class HostVIFInfo(osv_base.VersionedObject, base.ComparableVersionedObject,
+                  osv_base.VersionedObjectPrintableMixin):
     """
     Class describing a VIF class and its supported versions
     """
@@ -114,8 +116,8 @@ class HostVIFInfo(osv_base.VersionedObject, base.ComparableVersionedObject):
 
 
 @base.VersionedObjectRegistry.register
-class HostPluginInfo(osv_base.VersionedObject,
-                        base.ComparableVersionedObject):
+class HostPluginInfo(osv_base.VersionedObject, base.ComparableVersionedObject,
+                     osv_base.VersionedObjectPrintableMixin):
     """
     Class describing a plugin and its supported VIF classes
     """
@@ -152,7 +154,8 @@ class HostPluginInfo(osv_base.VersionedObject,
 
 
 @base.VersionedObjectRegistry.register
-class HostInfo(osv_base.VersionedObject, base.ComparableVersionedObject):
+class HostInfo(osv_base.VersionedObject, base.ComparableVersionedObject,
+               osv_base.VersionedObjectPrintableMixin):
     """
     Class describing a host host and its supported plugin classes
     """

os_vif/tests/unit/test_base.py

@@ -0,0 +1,77 @@
+# 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 copy
+import mock
+import six
+
+from oslo_serialization import jsonutils
+from oslo_versionedobjects import base
+from oslo_versionedobjects import fields
+
+from os_vif.objects import base as osv_base
+from os_vif.tests.unit import base as test_base
+
+
+class TestVersionedObjectPrintable(test_base.TestCase):
+    @base.VersionedObjectRegistry.register_if(False)
+    class OVOChild1(osv_base.VersionedObject,
+                    osv_base.VersionedObjectPrintableMixin):
+        fields = {
+            "child1_field1": fields.ListOfIntegersField()
+        }
+
+    @base.VersionedObjectRegistry.register_if(False)
+    class OVOParent(osv_base.VersionedObject,
+                    osv_base.VersionedObjectPrintableMixin,
+                    base.ComparableVersionedObject):
+        fields = {
+            "parent_field1": fields.ListOfObjectsField("OVOChild1"),
+            "parent_field2": fields.StringField(),
+        }
+
+    def setUp(self):
+        super(TestVersionedObjectPrintable, self).setUp()
+        child1_1 = self.OVOChild1(child1_field1=[1, 2, 3])
+        child1_2 = self.OVOChild1(child1_field1=[4, 5, 6])
+        self.obj = self.OVOParent(
+            parent_field1=[child1_1, child1_2],
+            parent_field2="test string")
+
+    def test_print_object(self):
+        out = str(self.obj)
+        self.assertIn("'child1_field1': [1, 2, 3]}", out)
+        self.assertIn("'child1_field1': [4, 5, 6]}", out)
+        cmp = str({'parent_field2': six.text_type("test string")})
+        cmp = cmp.replace('{', '').replace('}', '')
+        self.assertIn(str(cmp), out)
+
+    @mock.patch.object(base.VersionedObject, "obj_class_from_name",
+                       side_effect=[OVOParent, OVOChild1, OVOChild1])
+    def test_serialize_object(self, *mock):
+        """Test jsonutils serialization is not affected by this new mixin."""
+        obj_orig = copy.deepcopy(self.obj)
+        obj_orig_primitive = obj_orig.obj_to_primitive()
+        str_orig_primitive = jsonutils.dumps(obj_orig_primitive)
+        obj_new_primitive = jsonutils.loads(str_orig_primitive)
+        obj_new = self.OVOParent.obj_from_primitive(obj_new_primitive)
+        self.assertEqual(obj_orig_primitive, obj_new_primitive)
+        self.assertEqual(obj_orig, obj_new)
+
+    def test_import_non_ovo_class(self):
+        """Test VersionedObjectPrintable could be inherited by non-OVO classes.
+        """
+        class NonOVOClass(osv_base.VersionedObjectPrintableMixin):
+            def __str__(self):
+                return "NonOVOClass __str__ method"
+
+        self.assertEqual("NonOVOClass __str__ method", str(NonOVOClass()))