Use BACKGROUND_EXPORT_TASK_HANDLED_EXCEPTIONS to specify user handled…

… exceptions

docs/installation.rst

@@ -215,6 +215,15 @@ These configuration you can use with django-is-core in your django settings file
     def perform_action_before_export_task(request, queryset, filename, **kwargs):
         logger.info(f"Exporting result of the query ({queryset.query}) into the file '{filename}'.")
 
+.. attribute:: IS_CORE_BACKGROUND_EXPORT_TASK_CALLBACK_HANDLED_EXCEPTIONS
+
+  A list of exceptions declared as explicitly handled by the library user that may occur during
+  the background export. These exceptions do abort background export and trigger export_failed signal.
+  However, the background export task finishes successfully without a failure.
+
+    # Django settings
+    IS_CORE_BACKGROUND_EXPORT_TASK_CALLBACK_HANDLED_EXCEPTIONS = ('your.file.Exception1', 'your.file.Exception2')
+
 .. attribute:: IS_CORE_BACKGROUND_EXPORT_TASK_QUEUE
 
   The celery queue name which will be used for the background export.

is_core/config.py

@@ -50,6 +50,7 @@ def _get_auth_login_view():
     'BACKGROUND_EXPORT_TASK_SOFT_TIME_LIMIT': (60*60) - 5,
     'BACKGROUND_EXPORT_TASK_UPDATE_REQUEST_FUNCTION': None,
     'BACKGROUND_EXPORT_TASK_CALLBACK': None,
+    'BACKGROUND_EXPORT_TASK_CALLBACK_HANDLED_EXCEPTIONS': (),
     'BACKGROUND_EXPORT_TASK_QUEUE': None,
     'BACKGROUND_EXPORT_SERIALIZATION_LIMIT': 2000,
     'BACKGROUND_EXPORT_STORAGE_CLASS': 'django.core.files.storage.DefaultStorage',

is_core/contrib/background_export/tasks.py

@@ -101,12 +101,16 @@ def background_serialization(self, exported_file_pk, rest_context, language, req
 
         # Perform user-defined verification before saving exported file into the database.
         if settings.BACKGROUND_EXPORT_TASK_CALLBACK:
-            import_string(settings.BACKGROUND_EXPORT_TASK_CALLBACK)(
-                request=request,
-                queryset=queryset,
-                filename=filename,
-                exported_file=exported_file,
-            )
+            try:
+                import_string(settings.BACKGROUND_EXPORT_TASK_CALLBACK)(
+                    request=request,
+                    queryset=queryset,
+                    filename=filename,
+                    exported_file=exported_file,
+                )
+            except tuple(import_string(exc) for exc in settings.BACKGROUND_EXPORT_TASK_CALLBACK_HANDLED_EXCEPTIONS) as exc:
+                export_failure.send(sender=self.__class__, exception=exc)
+                return
 
         exported_file.file.save(filename, ContentFile(''))