enable use of replica database (#359)

* enable use of replica database

When you use replica database the django-auditlog try to write in the same database where object was read (replica). But this is a read only database and crash the application.

This changes saves always in the default database.

If you want to save in multiple databases or in a special one use `DATABASE_ROUTERS` to configure it.

Co-authored-by: Hasan Ramezani <hasan.r67@gmail.com>

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changes
 
+#### Improvements
+- feat: enable use of replica database (delegating the choice to `DATABASES_ROUTER`) ([#359](https://github.com/jazzband/django-auditlog/pull/359))
+
+#### Important notes
+- LogEntry no longer save to same database instance is using
+
 ## 1.0.0 (2022-01-24)
 
 ### Final

auditlog/models.py

@@ -67,13 +67,7 @@ class LogEntryManager(models.Manager):
                         content_type=kwargs.get("content_type"),
                         object_pk=kwargs.get("object_pk", ""),
                     ).delete()
-            # save LogEntry to same database instance is using
-            db = instance._state.db
-            return (
-                self.create(**kwargs)
-                if db is None or db == ""
-                else self.using(db).create(**kwargs)
-            )
+            return self.create(**kwargs)
         return None
 
     def get_for_object(self, instance):

auditlog_tests/tests.py

@@ -1,4 +1,5 @@
 import datetime
+import json
 
 import django
 from dateutil.tz import gettz
@@ -11,6 +12,7 @@ from django.http import HttpResponse
 from django.test import RequestFactory, TestCase
 from django.utils import dateformat, formats, timezone
 
+from auditlog.diff import model_instance_diff
 from auditlog.middleware import AuditlogMiddleware
 from auditlog.models import LogEntry
 from auditlog.registry import auditlog
@@ -149,6 +151,24 @@ class SimpleModelTest(TestCase):
         self.setUp()
         self.test_create()
 
+    def test_create_log_to_object_from_other_database(self):
+        msg = "The log should not try to write to the same database as the object"
+
+        instance = self.obj
+        # simulate object obtained from a different database (read only)
+        instance._state.db = "replica"
+
+        changes = model_instance_diff(None, instance)
+
+        log_entry = LogEntry.objects.log_create(
+            instance,
+            action=LogEntry.Action.CREATE,
+            changes=json.dumps(changes),
+        )
+        self.assertEqual(
+            log_entry._state.db, "default", msg=msg
+        )  # must be created in default database
+
 
 class AltPrimaryKeyModelTest(SimpleModelTest):
     def setUp(self):