Fixes #5913: Improve change logging (#5924)

* Initial work on #5913
* Provide per-line diff highlighting
* BulkDeteView should delete objects individually to secure a pre-change snapshot
* Add changelog tests for bulk operations

docs/additional-features/change-logging.md

@@ -1,6 +1,6 @@
 # Change Logging
 
-Every time an object in NetBox is created, updated, or deleted, a serialized copy of that object is saved to the database, along with meta data including the current time and the user associated with the change. These records form a persistent record of changes both for each individual object as well as NetBox as a whole. The global change log can be viewed by navigating to Other > Change Log.
+Every time an object in NetBox is created, updated, or deleted, a serialized copy of that object taken both before and after the change is saved to the database, along with meta data including the current time and the user associated with the change. These records form a persistent record of changes both for each individual object as well as NetBox as a whole. The global change log can be viewed by navigating to Other > Change Log.
 
 A serialized representation of the instance being modified is included in JSON format. This is similar to how objects are conveyed within the REST API, but does not include any nested representations. For instance, the `tenant` field of a site will record only the tenant's ID, not a representation of the tenant.
 

docs/release-notes/version-2.11.md

@@ -16,6 +16,10 @@ In addition to the new `mark_connected` boolean field, the REST API representati
 
 Devices can now be assigned to locations (formerly known as rack groups) within a site without needing to be assigned to a particular rack. This is handy for assigning devices to rooms or floors within a building where racks are not used. The `location` foreign key field has been added to the Device model to support this.
 
+#### Improved Change Logging ([#5913](https://github.com/netbox-community/netbox/issues/5913))
+
+The ObjectChange model (which is used to record the creation, modification, and deletion of NetBox objects) now explicitly records the pre-change and post-change state of each object, rather than only the post-change state. This was done to present a more clear depiction of each change being made, and to prevent the erroneous association of a previous unlogged change with its successor.
+
 ### Enhancements
 
 * [#5370](https://github.com/netbox-community/netbox/issues/5370) - Extend custom field support to organizational models
@@ -54,3 +58,6 @@ Devices can now be assigned to locations (formerly known as rack groups) within
   * Renamed `group` field to `location`
 * extras.CustomField
   * Added new custom field type: `multi-select`
+* extras.ObjectChange
+  * Added the `prechange_data` field
+  * Renamed `object_data` to `postchange_data`

netbox/circuits/migrations/0025_standardize_models.py

@@ -34,4 +34,14 @@ class Migration(migrations.Migration):
             name='id',
             field=models.BigAutoField(primary_key=True, serialize=False),
         ),
+        migrations.AddField(
+            model_name='circuittermination',
+            name='created',
+            field=models.DateField(auto_now_add=True, null=True),
+        ),
+        migrations.AddField(
+            model_name='circuittermination',
+            name='last_updated',
+            field=models.DateTimeField(auto_now=True, null=True),
+        ),
     ]

netbox/circuits/models.py

@@ -6,9 +6,8 @@ from dcim.fields import ASNField
 from dcim.models import CableTermination, PathEndpoint
 from extras.models import ObjectChange, TaggedItem
 from extras.utils import extras_features
-from netbox.models import BigIDModel, OrganizationalModel, PrimaryModel
+from netbox.models import BigIDModel, ChangeLoggingMixin, OrganizationalModel, PrimaryModel
 from utilities.querysets import RestrictedQuerySet
-from utilities.utils import serialize_object
 from .choices import *
 from .querysets import CircuitQuerySet
 
@@ -235,7 +234,7 @@ class Circuit(PrimaryModel):
         return self._get_termination('Z')
 
 
-class CircuitTermination(BigIDModel, PathEndpoint, CableTermination):
+class CircuitTermination(ChangeLoggingMixin, BigIDModel, PathEndpoint, CableTermination):
     circuit = models.ForeignKey(
         to='circuits.Circuit',
         on_delete=models.CASCADE,
@@ -289,18 +288,11 @@ class CircuitTermination(BigIDModel, PathEndpoint, CableTermination):
     def to_objectchange(self, action):
         # Annotate the parent Circuit
         try:
-            related_object = self.circuit
+            circuit = self.circuit
         except Circuit.DoesNotExist:
             # Parent circuit has been deleted
-            related_object = None
-
-        return ObjectChange(
-            changed_object=self,
-            object_repr=str(self),
-            action=action,
-            related_object=related_object,
-            object_data=serialize_object(self)
-        )
+            circuit = None
+        return super().to_objectchange(action, related_object=circuit)
 
     @property
     def parent(self):

netbox/dcim/models/device_component_templates.py

@@ -75,13 +75,7 @@ class ComponentTemplateModel(ChangeLoggingMixin, BigIDModel):
         except ObjectDoesNotExist:
             # The parent DeviceType has already been deleted
             device_type = None
-        return ObjectChange(
-            changed_object=self,
-            object_repr=str(self),
-            action=action,
-            related_object=device_type,
-            object_data=serialize_object(self)
-        )
+        return super().to_objectchange(action, related_object=device_type)
 
 
 @extras_features('custom_fields', 'export_templates', 'webhooks')

netbox/dcim/models/device_components.py

@@ -82,13 +82,7 @@ class ComponentModel(PrimaryModel):
         except ObjectDoesNotExist:
             # The parent Device has already been deleted
             device = None
-        return ObjectChange(
-            changed_object=self,
-            object_repr=str(self),
-            action=action,
-            related_object=device,
-            object_data=serialize_object(self)
-        )
+        return super().to_objectchange(action, related_object=device)
 
     @property
     def parent(self):

netbox/extras/api/serializers.py

@@ -338,7 +338,7 @@ class ObjectChangeSerializer(serializers.ModelSerializer):
         model = ObjectChange
         fields = [
             'id', 'url', 'time', 'user', 'user_name', 'request_id', 'action', 'changed_object_type',
-            'changed_object_id', 'changed_object', 'object_data',
+            'changed_object_id', 'changed_object', 'prechange_data', 'postchange_data',
         ]
 
     @swagger_serializer_method(serializer_or_field=serializers.DictField)

netbox/extras/migrations/0055_objectchange_data.py

@@ -0,0 +1,28 @@
+# Generated by Django 3.2b1 on 2021-03-03 20:30
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('extras', '0054_standardize_models'),
+    ]
+
+    operations = [
+        migrations.RenameField(
+            model_name='objectchange',
+            old_name='object_data',
+            new_name='postchange_data',
+        ),
+        migrations.AlterField(
+            model_name='objectchange',
+            name='postchange_data',
+            field=models.JSONField(blank=True, editable=False, null=True),
+        ),
+        migrations.AddField(
+            model_name='objectchange',
+            name='prechange_data',
+            field=models.JSONField(blank=True, editable=False, null=True),
+        ),
+    ]

netbox/extras/models/change_logging.py

@@ -67,15 +67,22 @@ class ObjectChange(BigIDModel):
         max_length=200,
         editable=False
     )
-    object_data = models.JSONField(
-        editable=False
+    prechange_data = models.JSONField(
+        editable=False,
+        blank=True,
+        null=True
+    )
+    postchange_data = models.JSONField(
+        editable=False,
+        blank=True,
+        null=True
     )
 
     objects = RestrictedQuerySet.as_manager()
 
     csv_headers = [
         'time', 'user', 'user_name', 'request_id', 'action', 'changed_object_type', 'changed_object_id',
-        'related_object_type', 'related_object_id', 'object_repr', 'object_data',
+        'related_object_type', 'related_object_id', 'object_repr', 'prechange_data', 'postchange_data',
     ]
 
     class Meta:
@@ -114,7 +121,8 @@ class ObjectChange(BigIDModel):
             self.related_object_type,
             self.related_object_id,
             self.object_repr,
-            self.object_data,
+            self.prechange_data,
+            self.postchange_data,
         )
 
     def get_action_class(self):

netbox/extras/signals.py

@@ -36,6 +36,9 @@ def _handle_changed_object(request, sender, instance, **kwargs):
     # Record an ObjectChange if applicable
     if hasattr(instance, 'to_objectchange'):
         objectchange = instance.to_objectchange(action)
+        # TODO: Move this to to_objectchange()
+        if hasattr(instance, '_prechange_snapshot'):
+            objectchange.prechange_data = instance._prechange_snapshot
         objectchange.user = request.user
         objectchange.request_id = request.id
         objectchange.save()
@@ -62,6 +65,9 @@ def _handle_deleted_object(request, sender, instance, **kwargs):
     # Record an ObjectChange if applicable
     if hasattr(instance, 'to_objectchange'):
         objectchange = instance.to_objectchange(ObjectChangeActionChoices.ACTION_DELETE)
+        # TODO: Move this to to_objectchange()
+        if hasattr(instance, '_prechange_snapshot'):
+            objectchange.prechange_data = instance._prechange_snapshot
         objectchange.user = request.user
         objectchange.request_id = request.id
         objectchange.save()

netbox/extras/tests/test_changelog.py

@@ -40,8 +40,8 @@ class ChangeLogViewTest(ModelViewTestCase):
     def test_create_object(self):
         tags = self.create_tags('Tag 1', 'Tag 2')
         form_data = {
-            'name': 'Test Site 1',
-            'slug': 'test-site-1',
+            'name': 'Site 1',
+            'slug': 'site-1',
             'status': SiteStatusChoices.STATUS_ACTIVE,
             'cf_my_field': 'ABC',
             'cf_my_field_select': 'Bar',
@@ -56,7 +56,7 @@ class ChangeLogViewTest(ModelViewTestCase):
         response = self.client.post(**request)
         self.assertHttpStatus(response, 302)
 
-        site = Site.objects.get(name='Test Site 1')
+        site = Site.objects.get(name='Site 1')
         # First OC is the creation; second is the tags update
         oc_list = ObjectChange.objects.filter(
             changed_object_type=ContentType.objects.get_for_model(Site),
@@ -64,20 +64,21 @@ class ChangeLogViewTest(ModelViewTestCase):
         ).order_by('pk')
         self.assertEqual(oc_list[0].changed_object, site)
         self.assertEqual(oc_list[0].action, ObjectChangeActionChoices.ACTION_CREATE)
-        self.assertEqual(oc_list[0].object_data['custom_fields']['my_field'], form_data['cf_my_field'])
-        self.assertEqual(oc_list[0].object_data['custom_fields']['my_field_select'], form_data['cf_my_field_select'])
+        self.assertEqual(oc_list[0].prechange_data, None)
+        self.assertEqual(oc_list[0].postchange_data['custom_fields']['my_field'], form_data['cf_my_field'])
+        self.assertEqual(oc_list[0].postchange_data['custom_fields']['my_field_select'], form_data['cf_my_field_select'])
         self.assertEqual(oc_list[1].action, ObjectChangeActionChoices.ACTION_UPDATE)
-        self.assertEqual(oc_list[1].object_data['tags'], ['Tag 1', 'Tag 2'])
+        self.assertEqual(oc_list[1].postchange_data['tags'], ['Tag 1', 'Tag 2'])
 
     def test_update_object(self):
-        site = Site(name='Test Site 1', slug='test-site-1')
+        site = Site(name='Site 1', slug='site-1')
         site.save()
         tags = self.create_tags('Tag 1', 'Tag 2', 'Tag 3')
         site.tags.set('Tag 1', 'Tag 2')
 
         form_data = {
-            'name': 'Test Site X',
-            'slug': 'test-site-x',
+            'name': 'Site X',
+            'slug': 'site-x',
             'status': SiteStatusChoices.STATUS_PLANNED,
             'cf_my_field': 'DEF',
             'cf_my_field_select': 'Foo',
@@ -100,14 +101,16 @@ class ChangeLogViewTest(ModelViewTestCase):
         ).first()
         self.assertEqual(oc.changed_object, site)
         self.assertEqual(oc.action, ObjectChangeActionChoices.ACTION_UPDATE)
-        self.assertEqual(oc.object_data['custom_fields']['my_field'], form_data['cf_my_field'])
-        self.assertEqual(oc.object_data['custom_fields']['my_field_select'], form_data['cf_my_field_select'])
-        self.assertEqual(oc.object_data['tags'], ['Tag 3'])
+        self.assertEqual(oc.prechange_data['name'], 'Site 1')
+        self.assertEqual(oc.prechange_data['tags'], ['Tag 1', 'Tag 2'])
+        self.assertEqual(oc.postchange_data['custom_fields']['my_field'], form_data['cf_my_field'])
+        self.assertEqual(oc.postchange_data['custom_fields']['my_field_select'], form_data['cf_my_field_select'])
+        self.assertEqual(oc.postchange_data['tags'], ['Tag 3'])
 
     def test_delete_object(self):
         site = Site(
-            name='Test Site 1',
-            slug='test-site-1',
+            name='Site 1',
+            slug='site-1',
             custom_field_data={
                 'my_field': 'ABC',
                 'my_field_select': 'Bar'
@@ -129,15 +132,83 @@ class ChangeLogViewTest(ModelViewTestCase):
         self.assertEqual(oc.changed_object, None)
         self.assertEqual(oc.object_repr, site.name)
         self.assertEqual(oc.action, ObjectChangeActionChoices.ACTION_DELETE)
-        self.assertEqual(oc.object_data['custom_fields']['my_field'], 'ABC')
-        self.assertEqual(oc.object_data['custom_fields']['my_field_select'], 'Bar')
-        self.assertEqual(oc.object_data['tags'], ['Tag 1', 'Tag 2'])
+        self.assertEqual(oc.prechange_data['custom_fields']['my_field'], 'ABC')
+        self.assertEqual(oc.prechange_data['custom_fields']['my_field_select'], 'Bar')
+        self.assertEqual(oc.prechange_data['tags'], ['Tag 1', 'Tag 2'])
+        self.assertEqual(oc.postchange_data, None)
+
+    def test_bulk_update_objects(self):
+        sites = (
+            Site(name='Site 1', slug='site-1', status=SiteStatusChoices.STATUS_ACTIVE),
+            Site(name='Site 2', slug='site-2', status=SiteStatusChoices.STATUS_ACTIVE),
+            Site(name='Site 3', slug='site-3', status=SiteStatusChoices.STATUS_ACTIVE),
+        )
+        Site.objects.bulk_create(sites)
+
+        form_data = {
+            'pk': [site.pk for site in sites],
+            '_apply': True,
+            'status': SiteStatusChoices.STATUS_PLANNED,
+            'description': 'New description',
+        }
+
+        request = {
+            'path': self._get_url('bulk_edit'),
+            'data': post_data(form_data),
+        }
+        self.add_permissions('dcim.view_site', 'dcim.change_site')
+        response = self.client.post(**request)
+        self.assertHttpStatus(response, 302)
+
+        objectchange = ObjectChange.objects.get(
+            changed_object_type=ContentType.objects.get_for_model(Site),
+            changed_object_id=sites[0].pk
+        )
+        self.assertEqual(objectchange.changed_object, sites[0])
+        self.assertEqual(objectchange.action, ObjectChangeActionChoices.ACTION_UPDATE)
+        self.assertEqual(objectchange.prechange_data['status'], SiteStatusChoices.STATUS_ACTIVE)
+        self.assertEqual(objectchange.prechange_data['description'], '')
+        self.assertEqual(objectchange.postchange_data['status'], form_data['status'])
+        self.assertEqual(objectchange.postchange_data['description'], form_data['description'])
+
+    def test_bulk_delete_objects(self):
+        sites = (
+            Site(name='Site 1', slug='site-1', status=SiteStatusChoices.STATUS_ACTIVE),
+            Site(name='Site 2', slug='site-2', status=SiteStatusChoices.STATUS_ACTIVE),
+            Site(name='Site 3', slug='site-3', status=SiteStatusChoices.STATUS_ACTIVE),
+        )
+        Site.objects.bulk_create(sites)
+
+        form_data = {
+            'pk': [site.pk for site in sites],
+            'confirm': True,
+            '_confirm': True,
+        }
+
+        request = {
+            'path': self._get_url('bulk_delete'),
+            'data': post_data(form_data),
+        }
+        self.add_permissions('dcim.delete_site')
+        response = self.client.post(**request)
+        self.assertHttpStatus(response, 302)
+
+        objectchange = ObjectChange.objects.get(
+            changed_object_type=ContentType.objects.get_for_model(Site),
+            changed_object_id=sites[0].pk
+        )
+        self.assertEqual(objectchange.changed_object_type, ContentType.objects.get_for_model(Site))
+        self.assertEqual(objectchange.changed_object_id, sites[0].pk)
+        self.assertEqual(objectchange.action, ObjectChangeActionChoices.ACTION_DELETE)
+        self.assertEqual(objectchange.prechange_data['name'], sites[0].name)
+        self.assertEqual(objectchange.prechange_data['slug'], sites[0].slug)
+        self.assertEqual(objectchange.postchange_data, None)
 
 
 class ChangeLogAPITest(APITestCase):
 
-    def setUp(self):
-        super().setUp()
+    @classmethod
+    def setUpTestData(cls):
 
         # Create a custom field on the Site model
         ct = ContentType.objects.get_for_model(Site)
@@ -169,8 +240,8 @@ class ChangeLogAPITest(APITestCase):
 
     def test_create_object(self):
         data = {
-            'name': 'Test Site 1',
-            'slug': 'test-site-1',
+            'name': 'Site 1',
+            'slug': 'site-1',
             'custom_fields': {
                 'my_field': 'ABC',
                 'my_field_select': 'Bar',
@@ -195,17 +266,18 @@ class ChangeLogAPITest(APITestCase):
         ).order_by('pk')
         self.assertEqual(oc_list[0].changed_object, site)
         self.assertEqual(oc_list[0].action, ObjectChangeActionChoices.ACTION_CREATE)
-        self.assertEqual(oc_list[0].object_data['custom_fields'], data['custom_fields'])
+        self.assertEqual(oc_list[0].prechange_data, None)
+        self.assertEqual(oc_list[0].postchange_data['custom_fields'], data['custom_fields'])
         self.assertEqual(oc_list[1].action, ObjectChangeActionChoices.ACTION_UPDATE)
-        self.assertEqual(oc_list[1].object_data['tags'], ['Tag 1', 'Tag 2'])
+        self.assertEqual(oc_list[1].postchange_data['tags'], ['Tag 1', 'Tag 2'])
 
     def test_update_object(self):
-        site = Site(name='Test Site 1', slug='test-site-1')
+        site = Site(name='Site 1', slug='site-1')
         site.save()
 
         data = {
-            'name': 'Test Site X',
-            'slug': 'test-site-x',
+            'name': 'Site X',
+            'slug': 'site-x',
             'custom_fields': {
                 'my_field': 'DEF',
                 'my_field_select': 'Foo',
@@ -229,13 +301,13 @@ class ChangeLogAPITest(APITestCase):
         ).first()
         self.assertEqual(oc.changed_object, site)
         self.assertEqual(oc.action, ObjectChangeActionChoices.ACTION_UPDATE)
-        self.assertEqual(oc.object_data['custom_fields'], data['custom_fields'])
-        self.assertEqual(oc.object_data['tags'], ['Tag 3'])
+        self.assertEqual(oc.postchange_data['custom_fields'], data['custom_fields'])
+        self.assertEqual(oc.postchange_data['tags'], ['Tag 3'])
 
     def test_delete_object(self):
         site = Site(
-            name='Test Site 1',
-            slug='test-site-1',
+            name='Site 1',
+            slug='site-1',
             custom_field_data={
                 'my_field': 'ABC',
                 'my_field_select': 'Bar'
@@ -255,6 +327,123 @@ class ChangeLogAPITest(APITestCase):
         self.assertEqual(oc.changed_object, None)
         self.assertEqual(oc.object_repr, site.name)
         self.assertEqual(oc.action, ObjectChangeActionChoices.ACTION_DELETE)
-        self.assertEqual(oc.object_data['custom_fields']['my_field'], 'ABC')
-        self.assertEqual(oc.object_data['custom_fields']['my_field_select'], 'Bar')
-        self.assertEqual(oc.object_data['tags'], ['Tag 1', 'Tag 2'])
+        self.assertEqual(oc.prechange_data['custom_fields']['my_field'], 'ABC')
+        self.assertEqual(oc.prechange_data['custom_fields']['my_field_select'], 'Bar')
+        self.assertEqual(oc.prechange_data['tags'], ['Tag 1', 'Tag 2'])
+        self.assertEqual(oc.postchange_data, None)
+
+    def test_bulk_create_objects(self):
+        data = (
+            {
+                'name': 'Site 1',
+                'slug': 'site-1',
+            },
+            {
+                'name': 'Site 2',
+                'slug': 'site-2',
+            },
+            {
+                'name': 'Site 3',
+                'slug': 'site-3',
+            },
+        )
+        self.assertEqual(ObjectChange.objects.count(), 0)
+        url = reverse('dcim-api:site-list')
+        self.add_permissions('dcim.add_site')
+
+        response = self.client.post(url, data, format='json', **self.header)
+        self.assertHttpStatus(response, status.HTTP_201_CREATED)
+        self.assertEqual(ObjectChange.objects.count(), 3)
+
+        site1 = Site.objects.get(pk=response.data[0]['id'])
+        objectchange = ObjectChange.objects.get(
+            changed_object_type=ContentType.objects.get_for_model(Site),
+            changed_object_id=site1.pk
+        )
+        self.assertEqual(objectchange.changed_object, site1)
+        self.assertEqual(objectchange.action, ObjectChangeActionChoices.ACTION_CREATE)
+        self.assertEqual(objectchange.prechange_data, None)
+        self.assertEqual(objectchange.postchange_data['name'], data[0]['name'])
+        self.assertEqual(objectchange.postchange_data['slug'], data[0]['slug'])
+
+    def test_bulk_edit_objects(self):
+        sites = (
+            Site(name='Site 1', slug='site-1'),
+            Site(name='Site 2', slug='site-2'),
+            Site(name='Site 3', slug='site-3'),
+        )
+        Site.objects.bulk_create(sites)
+
+        data = (
+            {
+                'id': sites[0].pk,
+                'name': 'Site A',
+                'slug': 'site-A',
+            },
+            {
+                'id': sites[1].pk,
+                'name': 'Site B',
+                'slug': 'site-b',
+            },
+            {
+                'id': sites[2].pk,
+                'name': 'Site C',
+                'slug': 'site-c',
+            },
+        )
+        self.assertEqual(ObjectChange.objects.count(), 0)
+        url = reverse('dcim-api:site-list')
+        self.add_permissions('dcim.change_site')
+
+        response = self.client.patch(url, data, format='json', **self.header)
+        self.assertHttpStatus(response, status.HTTP_200_OK)
+        self.assertEqual(ObjectChange.objects.count(), 3)
+
+        objectchange = ObjectChange.objects.get(
+            changed_object_type=ContentType.objects.get_for_model(Site),
+            changed_object_id=sites[0].pk
+        )
+        self.assertEqual(objectchange.changed_object, sites[0])
+        self.assertEqual(objectchange.action, ObjectChangeActionChoices.ACTION_UPDATE)
+        self.assertEqual(objectchange.prechange_data['name'], 'Site 1')
+        self.assertEqual(objectchange.prechange_data['slug'], 'site-1')
+        self.assertEqual(objectchange.postchange_data['name'], data[0]['name'])
+        self.assertEqual(objectchange.postchange_data['slug'], data[0]['slug'])
+
+    def test_bulk_delete_objects(self):
+        sites = (
+            Site(name='Site 1', slug='site-1'),
+            Site(name='Site 2', slug='site-2'),
+            Site(name='Site 3', slug='site-3'),
+        )
+        Site.objects.bulk_create(sites)
+
+        data = (
+            {
+                'id': sites[0].pk,
+            },
+            {
+                'id': sites[1].pk,
+            },
+            {
+                'id': sites[2].pk,
+            },
+        )
+        self.assertEqual(ObjectChange.objects.count(), 0)
+        url = reverse('dcim-api:site-list')
+        self.add_permissions('dcim.delete_site')
+
+        response = self.client.delete(url, data, format='json', **self.header)
+        self.assertHttpStatus(response, status.HTTP_204_NO_CONTENT)
+        self.assertEqual(ObjectChange.objects.count(), 3)
+
+        objectchange = ObjectChange.objects.get(
+            changed_object_type=ContentType.objects.get_for_model(Site),
+            changed_object_id=sites[0].pk
+        )
+        self.assertEqual(objectchange.changed_object_type, ContentType.objects.get_for_model(Site))
+        self.assertEqual(objectchange.changed_object_id, sites[0].pk)
+        self.assertEqual(objectchange.action, ObjectChangeActionChoices.ACTION_DELETE)
+        self.assertEqual(objectchange.prechange_data['name'], 'Site 1')
+        self.assertEqual(objectchange.prechange_data['slug'], 'site-1')
+        self.assertEqual(objectchange.postchange_data, None)

netbox/extras/tests/test_filters.py

@@ -327,7 +327,7 @@ class ObjectChangeTestCase(TestCase):
                 action=ObjectChangeActionChoices.ACTION_CREATE,
                 changed_object=site,
                 object_repr=str(site),
-                object_data={'name': site.name, 'slug': site.slug}
+                postchange_data={'name': site.name, 'slug': site.slug}
             ),
             ObjectChange(
                 user=users[0],
@@ -336,7 +336,7 @@ class ObjectChangeTestCase(TestCase):
                 action=ObjectChangeActionChoices.ACTION_UPDATE,
                 changed_object=site,
                 object_repr=str(site),
-                object_data={'name': site.name, 'slug': site.slug}
+                postchange_data={'name': site.name, 'slug': site.slug}
             ),
             ObjectChange(
                 user=users[1],
@@ -345,7 +345,7 @@ class ObjectChangeTestCase(TestCase):
                 action=ObjectChangeActionChoices.ACTION_DELETE,
                 changed_object=site,
                 object_repr=str(site),
-                object_data={'name': site.name, 'slug': site.slug}
+                postchange_data={'name': site.name, 'slug': site.slug}
             ),
             ObjectChange(
                 user=users[1],
@@ -354,7 +354,7 @@ class ObjectChangeTestCase(TestCase):
                 action=ObjectChangeActionChoices.ACTION_CREATE,
                 changed_object=ipaddress,
                 object_repr=str(ipaddress),
-                object_data={'address': ipaddress.address, 'status': ipaddress.status}
+                postchange_data={'address': ipaddress.address, 'status': ipaddress.status}
             ),
             ObjectChange(
                 user=users[2],
@@ -363,7 +363,7 @@ class ObjectChangeTestCase(TestCase):
                 action=ObjectChangeActionChoices.ACTION_UPDATE,
                 changed_object=ipaddress,
                 object_repr=str(ipaddress),
-                object_data={'address': ipaddress.address, 'status': ipaddress.status}
+                postchange_data={'address': ipaddress.address, 'status': ipaddress.status}
             ),
             ObjectChange(
                 user=users[2],
@@ -372,7 +372,7 @@ class ObjectChangeTestCase(TestCase):
                 action=ObjectChangeActionChoices.ACTION_DELETE,
                 changed_object=ipaddress,
                 object_repr=str(ipaddress),
-                object_data={'address': ipaddress.address, 'status': ipaddress.status}
+                postchange_data={'address': ipaddress.address, 'status': ipaddress.status}
             ),
         )
         ObjectChange.objects.bulk_create(object_changes)

netbox/extras/views.py

@@ -178,16 +178,18 @@ class ObjectChangeView(generic.ObjectView):
         next_change = objectchanges.filter(time__gt=instance.time).order_by('time').first()
         prev_change = objectchanges.filter(time__lt=instance.time).order_by('-time').first()
 
-        if prev_change:
+        if instance.prechange_data and instance.postchange_data:
             diff_added = shallow_compare_dict(
-                prev_change.object_data,
-                instance.object_data,
+                instance.prechange_data or dict(),
+                instance.postchange_data or dict(),
                 exclude=['last_updated'],
             )
-            diff_removed = {x: prev_change.object_data.get(x) for x in diff_added}
+            diff_removed = {
+                x: instance.prechange_data.get(x) for x in diff_added
+            } if instance.prechange_data else {}
         else:
-            # No previous change; this is the initial change that added the object
-            diff_added = diff_removed = instance.object_data
+            diff_added = None
+            diff_removed = None
 
         return {
             'diff_added': diff_added,

netbox/ipam/models/ip.py

@@ -649,13 +649,7 @@ class IPAddress(PrimaryModel):
 
     def to_objectchange(self, action):
         # Annotate the assigned object, if any
-        return ObjectChange(
-            changed_object=self,
-            object_repr=str(self),
-            action=action,
-            related_object=self.assigned_object,
-            object_data=serialize_object(self)
-        )
+        return super().to_objectchange(action, related_object=self.assigned_object)
 
     def to_csv(self):
 

netbox/netbox/api/views.py

@@ -76,6 +76,8 @@ class BulkUpdateModelMixin:
             data_list = []
             for obj in objects:
                 data = update_data.get(obj.id)
+                if hasattr(obj, 'snapshot'):
+                    obj.snapshot()
                 serializer = self.get_serializer(obj, data=data, partial=partial)
                 serializer.is_valid(raise_exception=True)
                 self.perform_update(serializer)
@@ -113,6 +115,8 @@ class BulkDestroyModelMixin:
     def perform_bulk_destroy(self, objects):
         with transaction.atomic():
             for obj in objects:
+                if hasattr(obj, 'snapshot'):
+                    obj.snapshot()
                 self.perform_destroy(obj)
 
 
@@ -127,6 +131,16 @@ class ModelViewSet(BulkUpdateModelMixin, BulkDestroyModelMixin, ModelViewSet_):
     brief = False
     brief_prefetch_fields = []
 
+    def get_object_with_snapshot(self):
+        """
+        Save a pre-change snapshot of the object immediately after retrieving it. This snapshot will be used to
+        record the "before" data in the changelog.
+        """
+        obj = super().get_object()
+        if hasattr(obj, 'snapshot'):
+            obj.snapshot()
+        return obj
+
     def get_serializer(self, *args, **kwargs):
 
         # If a list of objects has been provided, initialize the serializer with many=True
@@ -221,6 +235,11 @@ class ModelViewSet(BulkUpdateModelMixin, BulkDestroyModelMixin, ModelViewSet_):
         except ObjectDoesNotExist:
             raise PermissionDenied()
 
+    def update(self, request, *args, **kwargs):
+        # Hotwire get_object() to ensure we save a pre-change snapshot
+        self.get_object = self.get_object_with_snapshot
+        return super().update(request, *args, **kwargs)
+
     def perform_update(self, serializer):
         model = self.queryset.model
         logger = logging.getLogger('netbox.api.views.ModelViewSet')
@@ -234,6 +253,11 @@ class ModelViewSet(BulkUpdateModelMixin, BulkDestroyModelMixin, ModelViewSet_):
         except ObjectDoesNotExist:
             raise PermissionDenied()
 
+    def destroy(self, request, *args, **kwargs):
+        # Hotwire get_object() to ensure we save a pre-change snapshot
+        self.get_object = self.get_object_with_snapshot
+        return super().destroy(request, *args, **kwargs)
+
     def perform_destroy(self, instance):
         model = self.queryset.model
         logger = logging.getLogger('netbox.api.views.ModelViewSet')

netbox/netbox/models.py

@@ -1,3 +1,4 @@
+import logging
 from collections import OrderedDict
 
 from django.core.serializers.json import DjangoJSONEncoder
@@ -5,6 +6,7 @@ from django.core.validators import ValidationError
 from django.db import models
 from mptt.models import MPTTModel, TreeForeignKey
 
+from extras.choices import ObjectChangeActionChoices
 from utilities.mptt import TreeManager
 from utilities.utils import serialize_object
 
@@ -40,18 +42,32 @@ class ChangeLoggingMixin(models.Model):
     class Meta:
         abstract = True
 
-    def to_objectchange(self, action):
+    def snapshot(self):
+        """
+        Save a snapshot of the object's current state in preparation for modification.
+        """
+        logger = logging.getLogger('netbox')
+        logger.debug(f"Taking a snapshot of {self}")
+        self._prechange_snapshot = serialize_object(self)
+
+    def to_objectchange(self, action, related_object=None):
         """
         Return a new ObjectChange representing a change made to this object. This will typically be called automatically
         by ChangeLoggingMiddleware.
         """
         from extras.models import ObjectChange
-        return ObjectChange(
+        objectchange = ObjectChange(
             changed_object=self,
+            related_object=related_object,
             object_repr=str(self),
-            action=action,
-            object_data=serialize_object(self)
+            action=action
         )
+        if hasattr(self, '_prechange_snapshot'):
+            objectchange.prechange_data = self._prechange_snapshot
+        if action in (ObjectChangeActionChoices.ACTION_CREATE, ObjectChangeActionChoices.ACTION_UPDATE):
+            objectchange.postchange_data = serialize_object(self)
+
+        return objectchange
 
 
 class CustomFieldsMixin(models.Model):
@@ -164,16 +180,6 @@ class NestedGroupModel(ChangeLoggingMixin, CustomFieldsMixin, BigIDModel, MPTTMo
     def __str__(self):
         return self.name
 
-    def to_objectchange(self, action):
-        # Remove MPTT-internal fields
-        from extras.models import ObjectChange
-        return ObjectChange(
-            changed_object=self,
-            object_repr=str(self),
-            action=action,
-            object_data=serialize_object(self, exclude=['level', 'lft', 'rght', 'tree_id'])
-        )
-
 
 class OrganizationalModel(ChangeLoggingMixin, CustomFieldsMixin, BigIDModel):
     """

netbox/netbox/views/generic.py

@@ -218,11 +218,18 @@ class ObjectEditView(GetReturnURLMixin, ObjectPermissionRequiredMixin, View):
     def get_object(self, kwargs):
         # Look up an existing object by slug or PK, if provided.
         if 'slug' in kwargs:
-            return get_object_or_404(self.queryset, slug=kwargs['slug'])
+            obj = get_object_or_404(self.queryset, slug=kwargs['slug'])
         elif 'pk' in kwargs:
-            return get_object_or_404(self.queryset, pk=kwargs['pk'])
+            obj = get_object_or_404(self.queryset, pk=kwargs['pk'])
         # Otherwise, return a new instance.
-        return self.queryset.model()
+        else:
+            return self.queryset.model()
+
+        # Take a snapshot of change-logged models
+        if hasattr(obj, 'snapshot'):
+            obj.snapshot()
+
+        return obj
 
     def alter_obj(self, obj, request, url_args, url_kwargs):
         # Allow views to add extra info to an object before it is processed. For example, a parent object can be defined
@@ -328,9 +335,15 @@ class ObjectDeleteView(GetReturnURLMixin, ObjectPermissionRequiredMixin, View):
     def get_object(self, kwargs):
         # Look up object by slug if one has been provided. Otherwise, use PK.
         if 'slug' in kwargs:
-            return get_object_or_404(self.queryset, slug=kwargs['slug'])
+            obj = get_object_or_404(self.queryset, slug=kwargs['slug'])
         else:
-            return get_object_or_404(self.queryset, pk=kwargs['pk'])
+            obj = get_object_or_404(self.queryset, pk=kwargs['pk'])
+
+        # Take a snapshot of change-logged models
+        if hasattr(obj, 'snapshot'):
+            obj.snapshot()
+
+        return obj
 
     def get(self, request, **kwargs):
         obj = self.get_object(kwargs)
@@ -771,6 +784,10 @@ class BulkEditView(GetReturnURLMixin, ObjectPermissionRequiredMixin, View):
                         updated_objects = []
                         for obj in self.queryset.filter(pk__in=form.cleaned_data['pk']):
 
+                            # Take a snapshot of change-logged models
+                            if hasattr(obj, 'snapshot'):
+                                obj.snapshot()
+
                             # Update standard fields. If a field is listed in _nullify, delete its value.
                             for name in standard_fields:
 
@@ -898,6 +915,11 @@ class BulkRenameView(GetReturnURLMixin, ObjectPermissionRequiredMixin, View):
                     with transaction.atomic():
                         renamed_pks = []
                         for obj in selected_objects:
+
+                            # Take a snapshot of change-logged models
+                            if hasattr(obj, 'snapshot'):
+                                obj.snapshot()
+
                             find = form.cleaned_data['find']
                             replace = form.cleaned_data['replace']
                             if form.cleaned_data['use_regex']:
@@ -986,14 +1008,19 @@ class BulkDeleteView(GetReturnURLMixin, ObjectPermissionRequiredMixin, View):
 
                 # Delete objects
                 queryset = self.queryset.filter(pk__in=pk_list)
+                deleted_count = queryset.count()
                 try:
-                    deleted_count = queryset.delete()[1][model._meta.label]
+                    for obj in queryset:
+                        # Take a snapshot of change-logged models
+                        if hasattr(obj, 'snapshot'):
+                            obj.snapshot()
+                        obj.delete()
                 except ProtectedError as e:
                     logger.info("Caught ProtectedError while attempting to delete objects")
                     handle_protectederror(queryset, request, e)
                     return redirect(self.get_return_url(request))
 
-                msg = 'Deleted {} {}'.format(deleted_count, model._meta.verbose_name_plural)
+                msg = f"Deleted {deleted_count} {model._meta.verbose_name_plural}"
                 logger.info(msg)
                 messages.success(request, msg)
                 return redirect(self.get_return_url(request))

netbox/templates/extras/objectchange.html

@@ -83,6 +83,8 @@
                     </tr>
                 </table>
             </div>
+        </div>
+        <div class="col-md-7">
             <div class="panel panel-default">
                 <div class="panel-heading">
                     <strong>Difference</strong>
@@ -113,13 +115,39 @@
                 </div>
             </div>
         </div>
-        <div class="col-md-7">
+    </div>
+    <div class="row">
+        <div class="col-md-6">
+            <div class="panel panel-default">
+                <div class="panel-heading">
+                    <strong>Pre-Change Data</strong>
+                </div>
+                <div class="panel-body">
+                  {% if object.prechange_data %}
+                    <pre>{% for k, v in object.prechange_data.items %}{% spaceless %}
+                      <span{% if k in diff_removed %} style="background-color: #ffdce0"{% endif %}>{{ k }}: {{ v|render_json }}</span>
+                    {% endspaceless %}
+{% endfor %}</pre>
+                  {% else %}
+                    <span class="text-muted">None</span>
+                  {% endif %}
+                </div>
+            </div>
+        </div>
+        <div class="col-md-6">
             <div class="panel panel-default">
                 <div class="panel-heading">
-                    <strong>Object Data</strong>
+                    <strong>Post-Change Data</strong>
                 </div>
                 <div class="panel-body">
-                    <pre>{{ object.object_data|render_json }}</pre>
+                  {% if object.postchange_data %}
+                    <pre>{% for k, v in object.postchange_data.items %}{% spaceless %}
+                        <span{% if k in diff_added %} style="background-color: #cdffd8"{% endif %}>{{ k }}: {{ v|render_json }}</span>
+                      {% endspaceless %}
+{% endfor %}</pre>
+                  {% else %}
+                    <span class="text-muted">None</span>
+                  {% endif %}
                 </div>
             </div>
         </div>

netbox/utilities/utils.py

@@ -7,6 +7,7 @@ from django.core.serializers import serialize
 from django.db.models import Count, OuterRef, Subquery
 from django.db.models.functions import Coalesce
 from jinja2 import Environment
+from mptt.models import MPTTModel
 
 from dcim.choices import CableLengthUnitChoices
 from extras.utils import is_taggable
@@ -83,7 +84,7 @@ def count_related(model, field):
     return Coalesce(subquery, 0)
 
 
-def serialize_object(obj, extra=None, exclude=None):
+def serialize_object(obj, extra=None):
     """
     Return a generic JSON representation of an object using Django's built-in serializer. (This is used for things like
     change logging, not the REST API.) Optionally include a dictionary to supplement the object data. A list of keys
@@ -93,6 +94,11 @@ def serialize_object(obj, extra=None, exclude=None):
     json_str = serialize('json', [obj])
     data = json.loads(json_str)[0]['fields']
 
+    # Exclude any MPTTModel fields
+    if issubclass(obj.__class__, MPTTModel):
+        for field in ['level', 'lft', 'rght', 'tree_id']:
+            data.pop(field)
+
     # Include custom_field_data as "custom_fields"
     if hasattr(obj, 'custom_field_data'):
         data['custom_fields'] = data.pop('custom_field_data')
@@ -112,10 +118,6 @@ def serialize_object(obj, extra=None, exclude=None):
         if isinstance(key, str) and key.startswith('_'):
             data.pop(key)
 
-        # Explicitly excluded keys
-        if isinstance(exclude, (list, tuple)) and key in exclude:
-            data.pop(key)
-
     return data
 
 

netbox/virtualization/migrations/0020_standardize_models.py

@@ -44,4 +44,14 @@ class Migration(migrations.Migration):
             name='id',
             field=models.BigAutoField(primary_key=True, serialize=False),
         ),
+        migrations.AddField(
+            model_name='vminterface',
+            name='created',
+            field=models.DateField(auto_now_add=True, null=True),
+        ),
+        migrations.AddField(
+            model_name='vminterface',
+            name='last_updated',
+            field=models.DateTimeField(auto_now=True, null=True),
+        ),
     ]

netbox/virtualization/models.py

@@ -9,12 +9,11 @@ from dcim.models import BaseInterface, Device
 from extras.models import ConfigContextModel, ObjectChange, TaggedItem
 from extras.querysets import ConfigContextModelQuerySet
 from extras.utils import extras_features
-from netbox.models import BigIDModel, OrganizationalModel, PrimaryModel
+from netbox.models import BigIDModel, ChangeLoggingMixin, OrganizationalModel, PrimaryModel
 from utilities.fields import NaturalOrderingField
 from utilities.ordering import naturalize_interface
 from utilities.query_functions import CollateAsChar
 from utilities.querysets import RestrictedQuerySet
-from utilities.utils import serialize_object
 from .choices import *
 
 
@@ -373,8 +372,9 @@ class VirtualMachine(PrimaryModel, ConfigContextModel):
 # Interfaces
 #
 
+# TODO: Inherit from PrimaryModel
 @extras_features('export_templates', 'webhooks')
-class VMInterface(BigIDModel, BaseInterface):
+class VMInterface(ChangeLoggingMixin, BigIDModel, BaseInterface):
     virtual_machine = models.ForeignKey(
         to='virtualization.VirtualMachine',
         on_delete=models.CASCADE,
@@ -458,13 +458,7 @@ class VMInterface(BigIDModel, BaseInterface):
 
     def to_objectchange(self, action):
         # Annotate the parent VirtualMachine
-        return ObjectChange(
-            changed_object=self,
-            object_repr=str(self),
-            action=action,
-            related_object=self.virtual_machine,
-            object_data=serialize_object(self)
-        )
+        return super().to_objectchange(action, related_object=self.virtual_machine)
 
     @property
     def parent(self):