Merge 3bb9b05 into f426257

chamber/importers/__init__.py

@@ -131,7 +131,6 @@ def import_rows(self, reader, row_count=0):
                 batch.append(self.model_class(**self.get_fields_dict(row)))
         created += self.create_batch(batch)
         self._post_batch_create(len(batch), row_count)
-
         self._post_import_rows(created)
 
         return created

chamber/models/__init__.py

@@ -5,7 +5,7 @@
 from distutils.version import StrictVersion
 
 import django
-from django.db import models, transaction
+from django.db import models, transaction, OperationalError
 from django.db.models.base import ModelBase
 from django.utils.translation import ugettext_lazy as _
 from django.utils.functional import cached_property
@@ -519,6 +519,16 @@ def change_and_save(self, update_only_changed_fields=False, **changed_fields):
         change_and_save(self, update_only_changed_fields=update_only_changed_fields, **changed_fields)
         return self
 
+    def get_locked_instance(self):
+        """
+        Lock object and reload it from database.
+        :return: reloaded locked object from database
+        """
+        if not self.pk:
+            raise OperationalError('Unsaved object cannot be locked')
+
+        return self.__class__.objects.filter(pk=self.pk).select_for_update().get()
+
     class Meta:
         abstract = True