Use one-shot tasks for label print batches (#12939)

* Disable retries for label print batch tasks

* Remove label failure retry guard for one-shot jobs

src/backend/InvenTree/report/api.py

@@ -226,6 +226,7 @@ class LabelPrint(GenericAPIView):
             output.pk,
             user.pk if user else None,
             plugin.slug,
+            retry=False,
             options=(plugin_serializer.data if plugin_serializer else {}),
         )
 

src/backend/InvenTree/report/tasks.py

@@ -118,13 +118,6 @@ def print_labels(
         )
         return
 
-    if output.errors:
-        # A failed job may have printed some labels already - do not print them again
-        logger.info(
-            'DataOutput %s has already failed - skipping print_labels task', output_id
-        )
-        return
-
     # Fetch user information
     user = None
 

src/backend/InvenTree/report/tests.py

@@ -549,6 +549,38 @@ class LabelTest(InvenTreeAPITestCase):
                 output = plugin.get_generated_file(**kwargs)
                 self.assertEqual(output.name, expected)
 
+    def test_print_task_single_shot(self):
+        """API print jobs acknowledge failures without retrying the whole label batch."""
+        from django_q.models import OrmQ
+
+        OrmQ.objects.all().delete()
+
+        template = LabelTemplate.objects.filter(enabled=True, model_type='part').first()
+        part = Part.objects.first()
+
+        with patch('InvenTree.status.is_worker_running', return_value=True):
+            response = self.post(
+                reverse('api-label-print'),
+                data={'template': template.pk, 'items': [part.pk]},
+                expected_code=201,
+            )
+
+        task = OrmQ.objects.get()
+        self.assertEqual(task.func(), 'report.tasks.print_labels')
+        self.assertTrue(task.q_options().get('ack_failure'))
+        self.assertEqual(
+            task.args(),
+            (
+                template.pk,
+                [part.pk],
+                response.data['pk'],
+                self.user.pk,
+                'inventreelabel',
+            ),
+        )
+        self.assertEqual(task.kwargs(), {'options': {}})
+        self.assertFalse(response.data['complete'])
+
     def test_print_failure(self):
         """Printing failures retain their details and propagate to the caller."""
         template = LabelTemplate.objects.filter(enabled=True, model_type='part').first()
@@ -604,35 +636,6 @@ class LabelTest(InvenTreeAPITestCase):
                             'Error printing labels: printer unavailable',
                         )
 
-                    if worker:
-                        original = (
-                            report_models.DataOutput.objects
-                            .filter(pk=output.pk)
-                            .values()
-                            .get()
-                        )
-                        with patch.object(
-                            registry, 'get_plugin', return_value=plugin
-                        ) as get_plugin:
-                            print_labels(
-                                template.pk,
-                                [part.pk for part in parts],
-                                output.pk,
-                                self.user.pk,
-                                plugin.slug,
-                                options={},
-                            )
-
-                        get_plugin.assert_not_called()
-                        plugin.print_labels.assert_called_once()
-                        self.assertEqual(
-                            report_models.DataOutput.objects
-                            .filter(pk=output.pk)
-                            .values()
-                            .get(),
-                            original,
-                        )
-
     def test_print_unavailable_plugin(self):
         """An unavailable worker plugin records a failure instead of hanging."""
         template = LabelTemplate.objects.filter(enabled=True, model_type='part').first()
@@ -660,23 +663,6 @@ class LabelTest(InvenTreeAPITestCase):
             {'error': "Label printing plugin 'unavailable-label' not found"},
         )
 
-        original = report_models.DataOutput.objects.filter(pk=output.pk).values().get()
-        plugin = Mock(spec=['slug', 'print_labels'], slug=output.plugin)
-        with (
-            patch.object(registry, 'get_plugin', return_value=plugin) as get_plugin,
-            patch.object(LabelTemplate, 'print') as print_template,
-        ):
-            print_labels(
-                template.pk, [], output.pk, self.user.pk, output.plugin, options={}
-            )
-
-        get_plugin.assert_not_called()
-        print_template.assert_not_called()
-        self.assertEqual(
-            report_models.DataOutput.objects.filter(pk=output.pk).values().get(),
-            original,
-        )
-
     def test_print_task_duplicate(self):
         """Duplicate tasks skip completed or deleted outputs before plugin lookup."""
         template = LabelTemplate.objects.filter(enabled=True, model_type='part').first()