store denormalized metadata about ActivityStream.actor for accounting

see: https://github.com/ansible/tower/issues/1782

awx/api/serializers.py

@@ -4831,6 +4831,9 @@ class ActivityStreamSerializer(BaseSerializer):
                                            username = obj.actor.username,
                                            first_name = obj.actor.first_name,
                                            last_name = obj.actor.last_name)
+        elif obj.deleted_actor:
+            summary_fields['actor'] = obj.deleted_actor.copy()
+            summary_fields['actor']['id'] = None
         if obj.setting:
             summary_fields['setting'] = [obj.setting]
         return summary_fields

awx/main/migrations/0038_v330_add_deleted_activitystream_actor.py

@@ -0,0 +1,24 @@
+#d -*- coding: utf-8 -*-
+# Generated by Django 1.11.11 on 2018-05-21 19:51
+from __future__ import unicode_literals
+
+import awx.main.fields
+import awx.main.models.activity_stream
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('main', '0037_v330_remove_legacy_fact_cleanup'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='activitystream',
+            name='deleted_actor',
+            field=awx.main.fields.JSONField(null=True),
+        ),
+    ]

awx/main/models/activity_stream.py

@@ -33,6 +33,7 @@ class ActivityStream(models.Model):
     operation = models.CharField(max_length=13, choices=OPERATION_CHOICES)
     timestamp = models.DateTimeField(auto_now_add=True)
     changes = models.TextField(blank=True)
+    deleted_actor = JSONField(null=True)
 
     object_relationship_type = models.TextField(blank=True)
     object1 = models.TextField()
@@ -77,6 +78,18 @@ class ActivityStream(models.Model):
         return reverse('api:activity_stream_detail', kwargs={'pk': self.pk}, request=request)
 
     def save(self, *args, **kwargs):
+        # Store denormalized actor metadata so that we retain it for accounting
+        # purposes when the User row is deleted.
+        if self.actor:
+            self.deleted_actor = {
+                'id': self.actor_id,
+                'username': self.actor.username,
+                'first_name': self.actor.first_name,
+                'last_name': self.actor.last_name,
+            }
+            if 'update_fields' in kwargs and 'deleted_actor' not in kwargs['update_fields']:
+                kwargs['update_fields'].append('deleted_actor')
+
         # For compatibility with Django 1.4.x, attempt to handle any calls to
         # save that pass update_fields.
         try:

awx/main/tests/functional/models/test_activity_stream.py

@@ -184,6 +184,32 @@ def test_annon_user_action():
     assert not entry.actor
 
 
+@pytest.mark.django_db
+def test_activity_stream_deleted_actor(alice, bob):
+    alice.first_name = 'Alice'
+    alice.last_name = 'Doe'
+    alice.save()
+    with impersonate(alice):
+        o = Organization.objects.create(name='test organization')
+    entry = o.activitystream_set.get(operation='create')
+    assert entry.actor == alice
+
+    alice.delete()
+    entry = o.activitystream_set.get(operation='create')
+    assert entry.actor is None
+    deleted = entry.deleted_actor
+    assert deleted['username'] == 'alice'
+    assert deleted['first_name'] == 'Alice'
+    assert deleted['last_name'] == 'Doe'
+
+    entry.actor = bob
+    entry.save(update_fields=['actor'])
+    deleted = entry.deleted_actor
+
+    entry = ActivityStream.objects.get(id=entry.pk)
+    assert entry.deleted_actor['username'] == 'bob'
+
+
 @pytest.mark.django_db
 def test_modified_not_allowed_field(somecloud_type):
     '''

awx/ui/client/src/activity-stream/activitystream.controller.js

@@ -53,8 +53,12 @@ export default ['$scope', '$state', 'subTitle', 'GetTargetTitle',
             $scope.activities.forEach(function(activity, i) {
                 // build activity.user
                 if ($scope.activities[i].summary_fields.actor) {
-                    $scope.activities[i].user = "<a href=\"/#/users/" + $scope.activities[i].summary_fields.actor.id  + "\">" +
-                        $scope.activities[i].summary_fields.actor.username + "</a>";
+                    if ($scope.activities[i].summary_fields.actor.id) {
+                        $scope.activities[i].user = "<a href=\"/#/users/" + $scope.activities[i].summary_fields.actor.id  + "\">" +
+                            $scope.activities[i].summary_fields.actor.username + "</a>";
+                    } else {
+                        $scope.activities[i].user = $scope.activities[i].summary_fields.actor.username + ' (deleted)';
+                    }
                 } else {
                     $scope.activities[i].user = 'system';
                 }