Adds a background task to remove StockItem objects which are scheduled for deletion

InvenTree/InvenTree/apps.py

@@ -63,6 +63,13 @@ class InvenTreeConfig(AppConfig):
             schedule_type=Schedule.DAILY,
         )
 
+        # Delete "old" stock items
+        InvenTree.tasks.schedule_task(
+            'stock.tasks.delete_old_stock_items',
+            schedule_type=Schedule.MINUTES,
+            minutes=30,
+        )
+
     def update_exchange_rates(self):
         """
         Update exchange rates each time the server is started, *if*:

InvenTree/stock/models.py

@@ -216,6 +216,11 @@ class StockItem(MPTTModel):
     # A query filter which can be used to filter StockItem objects which have expired
     EXPIRED_FILTER = IN_STOCK_FILTER & ~Q(expiry_date=None) & Q(expiry_date__lt=datetime.now().date())
 
+    def mark_for_deletion(self):
+
+        self.scheduled_for_deletion = True
+        self.save()
+
     def save(self, *args, **kwargs):
         """
         Save this StockItem to the database. Performs a number of checks:
@@ -1300,10 +1305,10 @@ class StockItem(MPTTModel):
 
         self.quantity = quantity
 
-        if quantity == 0 and self.delete_on_deplete and self.can_delete():
 
-            # TODO - Do not actually "delete" stock at this point - instead give it a "DELETED" flag
+        if quantity == 0 and self.delete_on_deplete and self.can_delete():
-            self.delete()
+            self.mark_for_deletion()
+
             return False
         else:
             self.save()

InvenTree/stock/tasks.py

@@ -0,0 +1,35 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+import logging
+
+from django.core.exceptions import AppRegistryNotReady
+
+
+logger = logging.getLogger('inventree')
+
+
+def delete_old_stock_items():
+    """
+    This function removes StockItem objects which have been marked for deletion.
+
+    Bulk "delete" operations for database entries with foreign-key relationships
+    can be pretty expensive, and thus can "block" the UI for a period of time.
+
+    Thus, instead of immediately deleting multiple StockItems, some UI actions
+    simply mark each StockItem as "scheduled for deletion".
+
+    The background worker then manually deletes these at a later stage
+    """
+
+    try:
+        from stock.models import StockItem
+    except AppRegistryNotReady:
+        logger.info("Could not delete scheduled StockItems - AppRegistryNotReady")
+        return
+
+    items = StockItem.objects.filter(scheduled_for_deletion=True)
+
+    logger.info(f"Removing {items.count()} StockItem objects scheduled for deletion")
+
+    items.delete()