Merge pull request #17 from maxipavlovic/feature/LITE-17439

LITE-17439 Optimized CQRS sync to not make excessive queries to DB

Author: marcserrat

dj_cqrs/mixins.py

@@ -105,17 +105,18 @@ def _save_tracked_fields(self):
             tracker = getattr(self, FIELDS_TRACKER_FIELD_NAME)
             setattr(self, TRACKED_FIELDS_ATTR_NAME, tracker.changed())
 
-    def to_cqrs_dict(self, using=None):
+    def to_cqrs_dict(self, using=None, sync=False):
         """CQRS serialization for transport payload.
 
         :param using: The using argument can be used to force the database
                       to use, defaults to None
         :type using: str, optional
+        :type sync: bool, optional
         :return: The serialized instance data.
         :rtype: dict
         """
         if self.CQRS_SERIALIZER:
-            data = self._class_serialization(using)
+            data = self._class_serialization(using, sync=sync)
         else:
             self._refresh_f_expr_values(using)
             data = self._common_serialization(using)
@@ -230,13 +231,16 @@ def _common_serialization(self, using):
 
         return data
 
-    def _class_serialization(self, using):
-        db = using if using is not None else self._state.db
-        qs = self.__class__._default_manager.using(db).filter(pk=self.pk)
+    def _class_serialization(self, using, sync=False):
+        if sync:
+            instance = self
+        else:
+            db = using if using is not None else self._state.db
+            qs = self.__class__._default_manager.using(db).filter(pk=self.pk)
 
-        instance = self.relate_cqrs_serialization(qs).first()
-        if not instance:
-            raise RuntimeError("Couldn't serialize CQRS class ({}).".format(self.CQRS_ID))
+            instance = self.relate_cqrs_serialization(qs).first()
+            if not instance:
+                raise RuntimeError("Couldn't serialize CQRS class ({}).".format(self.CQRS_ID))
 
         data = self._cqrs_serializer_cls(instance).data
         data['cqrs_revision'] = instance.cqrs_revision
@@ -264,8 +268,8 @@ def _refresh_f_expr_values(self, using):
             if value is not None and isinstance(value, CombinedExpression):
                 fields_to_refresh.append(f.name)
 
-            if fields_to_refresh:
-                self.refresh_from_db(fields=fields_to_refresh)
+        if fields_to_refresh:
+            self.refresh_from_db(fields=fields_to_refresh)
 
     @property
     def _cqrs_serializer_cls(self):

dj_cqrs/signals.py

@@ -59,7 +59,7 @@ def post_save(cls, sender, **kwargs):
         connection = transaction.get_connection(using)
         if not connection.in_atomic_block:
             instance.reset_cqrs_saves_count()
-            instance_data = instance.to_cqrs_dict(using)
+            instance_data = instance.to_cqrs_dict(using, sync=sync)
             previous_data = instance.get_tracked_fields_data()
             signal_type = SignalType.SYNC if sync else SignalType.SAVE
             payload = TransportPayload(

tests/test_flow.py

@@ -144,6 +144,7 @@ def test_sync_exists(mocker):
     author.save()
     mocker.stopall()
 
+    author.refresh_from_db()
     author.cqrs_sync()
 
     assert replica_models.AuthorRef.objects.count() == 1

tests/test_master/test_mixin.py

@@ -201,6 +201,28 @@ def test_cqrs_sync(mocker):
     )
 
 
+@pytest.mark.django_db(transaction=True)
+def test_cqrs_sync_optimized_for_class_serialization(mocker, django_assert_num_queries):
+    models.Author.objects.create(
+        id=5,
+        name='hi',
+        publisher=models.Publisher.objects.create(id=1, name='pub'),
+    )
+    m = models.Author.relate_cqrs_serialization(models.Author.objects.all()).first()
+
+    publisher_mock = mocker.patch('dj_cqrs.controller.producer.produce')
+    with django_assert_num_queries(0):
+        assert m.cqrs_sync()
+
+    assert_publisher_once_called_with_args(
+        publisher_mock,
+        SignalType.SYNC,
+        models.Author.CQRS_ID,
+        {'id': 5, 'name': 'hi', 'publisher': {'id': 1, 'name': 'pub'}},
+        5,
+    )
+
+
 @pytest.mark.django_db(transaction=True)
 def test_is_sync_instance(mocker):
     publisher_mock = mocker.patch('dj_cqrs.controller.producer.produce')