enable use of replica database

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 #### Improvements
 
+- feat: enable use of replica database (delegating the choice to `DATABASES_ROUTER`) ([#359](https://github.com/jazzband/django-auditlog/pull/359))
 - build: add classifiers for Python and Django
 - build: replace django-jsonfield with django-jsonfield-backport ([#339](https://github.com/jazzband/django-auditlog/pull/339))
 - ci: replace Travis with Github Actions

auditlog/models.py

@@ -67,13 +67,7 @@ def log_create(self, instance, **kwargs):
                         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
@@ -10,7 +11,9 @@
 from django.http import HttpResponse
 from django.test import RequestFactory, TestCase
 from django.utils import dateformat, formats, timezone
+from django.utils.connection import ConnectionDoesNotExist
 
+from auditlog.diff import model_instance_diff
 from auditlog.middleware import AuditlogMiddleware
 from auditlog.models import LogEntry
 from auditlog.registry import auditlog
@@ -920,3 +923,31 @@ def test_no_delete_related(self):
             list(entries.values_list("action", flat=True)),
             [LogEntry.Action.CREATE, LogEntry.Action.UPDATE, LogEntry.Action.DELETE],
         )
+
+
+class ModelFromDifferentDatabase(TestCase):
+    """
+    Should use the default database even when object is from other database (read-only, for example)
+    """
+    def setUp(self):
+        self.obj = SimpleModel.objects.create(text="42 is the answer")
+
+    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
+        instance._state.db = 'replica'  # simulate object obtained from a different database (read only)
+
+        changes = model_instance_diff(None, instance)
+
+        try:
+            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
+        except ConnectionDoesNotExist as e:
+            self.assertTrue(False, msg=msg)
+
+