Clean up duplicated change-building code in objects

Almost every object thus far has done this:

  changes = {}
  for key in self.obj_what_changed():
      changes[key] = self[key]

to get a dict of updates to apply to the database. This patch adds
that as part of the base object and makes every place that does
the above to just use that.

Change-Id: I847f5d35181b0305668b107f86faa164e71c3375

nova/objects/aggregate.py

@@ -55,9 +55,7 @@ class Aggregate(base.NovaPersistentObject, base.NovaObject):
     @base.remotable
     def create(self, context):
         self._assert_no_hosts('create')
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
         payload = dict(updates)
         if 'metadata' in updates:
             # NOTE(danms): For some reason the notification format is weird
@@ -76,9 +74,7 @@ class Aggregate(base.NovaPersistentObject, base.NovaObject):
     @base.remotable
     def save(self, context):
         self._assert_no_hosts('save')
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
 
         payload = {'aggregate_id': self.id}
         if 'metadata' in updates:

nova/objects/base.py

@@ -317,6 +317,13 @@ class NovaObject(object):
         """Returns a set of fields that have been modified."""
         return self._changed_fields
 
+    def obj_get_changes(self):
+        """Returns a dict of changed fields and their new values."""
+        changes = {}
+        for key in self.obj_what_changed():
+            changes[key] = self[key]
+        return changes
+
     def obj_reset_changes(self, fields=None):
         """Reset the list of fields that have been changed.
 

nova/objects/compute_node.py

@@ -62,17 +62,13 @@ class ComputeNode(base.NovaPersistentObject, base.NovaObject):
 
     @base.remotable
     def create(self, context):
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
         db_compute = db.compute_node_create(context, updates)
         self._from_db_object(context, self, db_compute)
 
     @base.remotable
     def save(self, context, prune_stats=False):
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
         updates.pop('id', None)
         db_compute = db.compute_node_update(context, self.id, updates,
                                             prune_stats=prune_stats)

nova/objects/instance.py

@@ -319,9 +319,8 @@ class Instance(base.NovaPersistentObject, base.NovaObject):
         if self.obj_attr_is_set('id'):
             raise exception.ObjectActionError(action='create',
                                               reason='already created')
-        updates = {}
+        updates = self.obj_get_changes()
-        for attr in self.obj_what_changed() - set(['id']):
+        updates.pop('id', None)
-            updates[attr] = self[attr]
         expected_attrs = [attr for attr in INSTANCE_DEFAULT_FIELDS
                           if attr in updates]
         if 'security_groups' in updates:

nova/objects/instance_group.py

@@ -64,10 +64,7 @@ class InstanceGroup(base.NovaPersistentObject, base.NovaObject):
     def save(self, context):
         """Save updates to this instance group."""
 
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
-
         if not updates:
             return
 
@@ -95,10 +92,7 @@ class InstanceGroup(base.NovaPersistentObject, base.NovaObject):
         if self.obj_attr_is_set('id'):
             raise exception.ObjectActionError(action='create',
                                               reason='already created')
-        updates = {}
+        updates = self.obj_get_changes()
-        for attr in self.obj_what_changed():
-            updates[attr] = self[attr]
-
         updates.pop('id', None)
         policies = updates.pop('policies', None)
         members = updates.pop('members', None)

nova/objects/keypair.py

@@ -45,9 +45,7 @@ class KeyPair(base.NovaPersistentObject, base.NovaObject):
 
     @base.remotable
     def create(self, context):
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
         db_keypair = db.key_pair_create(context, updates)
         self._from_db_object(context, self, db_keypair)
 

nova/objects/migration.py

@@ -53,18 +53,14 @@ class Migration(base.NovaPersistentObject, base.NovaObject):
 
     @base.remotable
     def create(self, context):
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
         updates.pop('id', None)
         db_migration = db.migration_create(context, updates)
         self._from_db_object(context, self, db_migration)
 
     @base.remotable
     def save(self, context):
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
         updates.pop('id', None)
         db_migration = db.migration_update(context, self.id, updates)
         self._from_db_object(context, self, db_migration)

nova/objects/pci_device.py

@@ -230,12 +230,9 @@ class PciDevice(base.NovaPersistentObject, base.NovaObject):
             self.status = 'deleted'
             db.pci_device_destroy(context, self.compute_node_id, self.address)
         elif self.status != 'deleted':
-            updates = {}
+            updates = self.obj_get_changes()
-            for field in self.obj_what_changed():
+            if 'extra_info' in updates:
-                if field == 'extra_info':
+                updates['extra_info'] = jsonutils.dumps(updates['extra_info'])
-                    updates['extra_info'] = jsonutils.dumps(self.extra_info)
-                else:
-                    updates[field] = self[field]
             if updates:
                 db_pci = db.pci_device_update(context, self.compute_node_id,
                                               self.address, updates)

nova/objects/security_group.py

@@ -51,9 +51,7 @@ class SecurityGroup(base.NovaPersistentObject, base.NovaObject):
 
     @base.remotable
     def save(self, context):
-        updates = {}
+        updates = self.obj_get_changes()
-        for field in self.obj_what_changed():
-            updates[field] = self[field]
         if updates:
             db_secgroup = db.security_group_update(context, self.id, updates)
             SecurityGroup._from_db_object(self, db_secgroup)

nova/objects/service.py

@@ -99,17 +99,13 @@ class Service(base.NovaPersistentObject, base.NovaObject):
 
     @base.remotable
     def create(self, context):
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
         db_service = db.service_create(context, updates)
         self._from_db_object(context, self, db_service)
 
     @base.remotable
     def save(self, context):
-        updates = {}
+        updates = self.obj_get_changes()
-        for key in self.obj_what_changed():
-            updates[key] = self[key]
         updates.pop('id', None)
         db_service = db.service_update(context, self.id, updates)
         self._from_db_object(context, self, db_service)

nova/tests/objects/test_objects.py

@@ -557,6 +557,16 @@ class _TestObject(object):
         self.assertEqual(set(myobj_fields) | set(myobj3_fields),
                          set(TestSubclassedObject.fields.keys()))
 
+    def test_get_changes(self):
+        obj = MyObj()
+        self.assertEqual({}, obj.obj_get_changes())
+        obj.foo = 123
+        self.assertEqual({'foo': 123}, obj.obj_get_changes())
+        obj.bar = 'test'
+        self.assertEqual({'foo': 123, 'bar': 'test'}, obj.obj_get_changes())
+        obj.obj_reset_changes()
+        self.assertEqual({}, obj.obj_get_changes())
+
 
 class TestObject(_LocalTest, _TestObject):
     pass