chore(aci): add unique together constraint on DetectorWorkflow (#87464)

each detector-workflow pair should only have 1 connection

Author: ameliahsu

migrations_lockfile.txt

@@ -25,4 +25,4 @@ tempest: 0002_make_message_type_nullable
 
 uptime: 0031_translate_uptime_object_headers_to_lists_take_three
 
-workflow_engine: 0037_rm_workflow_name_unique_constraint
+workflow_engine: 0038_add_detector_workflow_unique_together

src/sentry/workflow_engine/migrations/0038_add_detector_workflow_unique_together.py

@@ -0,0 +1,32 @@
+# Generated by Django 5.1.7 on 2025-03-19 23:14
+
+from django.db import migrations
+
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+    # This flag is used to mark that a migration shouldn't be automatically run in production.
+    # This should only be used for operations where it's safe to run the migration after your
+    # code has deployed. So this should not be used for most operations that alter the schema
+    # of a table.
+    # Here are some things that make sense to mark as post deployment:
+    # - Large data migrations. Typically we want these to be run manually so that they can be
+    #   monitored and not block the deploy for a long period of time while they run.
+    # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
+    #   run this outside deployments so that we don't block them. Note that while adding an index
+    #   is a schema change, it's completely safe to run the operation after the code has deployed.
+    # Once deployed, run these manually via: https://develop.sentry.dev/database-migrations/#migration-deployment
+
+    is_post_deployment = False
+
+    dependencies = [
+        ("workflow_engine", "0037_rm_workflow_name_unique_constraint"),
+    ]
+
+    operations = [
+        migrations.AlterUniqueTogether(
+            name="detectorworkflow",
+            unique_together={("detector", "workflow")},
+        ),
+    ]

src/sentry/workflow_engine/models/detector_workflow.py

@@ -14,3 +14,6 @@ class DetectorWorkflow(DefaultFieldsModel):
 
     detector = FlexibleForeignKey("workflow_engine.Detector", on_delete=models.CASCADE)
     workflow = FlexibleForeignKey("workflow_engine.Workflow", on_delete=models.CASCADE)
+
+    class Meta:
+        unique_together = (("detector", "workflow"),)