feat: ensure the Routine.attempt_count is always less or equal to max…

…_retries

django_cloud_tasks/migrations/0003_alter_routine_max_retries_and_more.py

@@ -0,0 +1,24 @@
+# Generated by Django 4.2.1 on 2023-07-12 22:34
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("django_cloud_tasks", "0002_alter_routine_status_alter_routine_task_name"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="routine",
+            name="max_retries",
+            field=models.PositiveIntegerField(default=20),
+        ),
+        migrations.AddConstraint(
+            model_name="routine",
+            constraint=models.CheckConstraint(
+                check=models.Q(("max_retries__gte", models.F("attempt_count"))),
+                name="max_retries_less_than_attempt_count",
+            ),
+        ),
+    ]

django_cloud_tasks/models.py

@@ -51,7 +51,7 @@ class Statuses(models.TextChoices):
         encoder=serializers.JSONEncoder,
     )
     attempt_count = models.PositiveIntegerField(default=0)
-    max_retries = models.PositiveIntegerField(null=True)
+    max_retries = models.PositiveIntegerField(default=20)
     output = models.JSONField(
         null=True,
         blank=True,
@@ -77,6 +77,14 @@ class Statuses(models.TextChoices):
         related_name="dependent_routines",
     )
 
+    class Meta:
+        constraints = (
+            models.CheckConstraint(
+                name="max_retries_less_than_attempt_count",
+                check=models.Q(max_retries__gte=models.F("attempt_count")),
+            ),
+        )
+
     def fail(self, output: dict) -> None:
         self.output = output
         self.status = self.Statuses.FAILED

django_cloud_tasks/tasks/routine_task.py

@@ -45,7 +45,7 @@ def process_routine(self, routine: models.Routine):
             logger.info(f"Routine #{routine.pk} is already completed")
             return
 
-        if routine.max_retries and routine.attempt_count >= routine.max_retries:
+        if routine.attempt_count >= routine.max_retries:
             error_message = f"Routine #{routine.pk} has exhausted retries and is being reverted"
             logger.info(error_message)
             routine.fail(output={"error": error_message})

sample_project/sample_app/tests/tests_models.py

@@ -5,7 +5,7 @@
 from django.test import TestCase
 from django.utils import timezone
 from freezegun import freeze_time
-
+from django.db import IntegrityError
 from django_cloud_tasks import models
 from django_cloud_tasks.tests import factories
 
@@ -145,6 +145,12 @@ def test_add_next(self):
         self.assertEqual(expected_routine_1["body"], next_routine.body)
         self.assertEqual(expected_routine_1["task_name"], next_routine.task_name)
 
+    def test_ensure_max_retries_greater_than_attempt_count(self):
+        with self.assertRaisesRegex(
+            expected_exception=IntegrityError, expected_regex="constraint failed: max_retries_less_than_attempt_count"
+        ):
+            factories.RoutineFactory(max_retries=1, attempt_count=5)
+
 
 class PipelineModelTest(TestCase):
     def test_start_pipeline(self):