fix(api): disable mongoose autoCreate in check-alerts worker (#3308)

.changeset/disable-check-alerts-autocreate.md

@@ -0,0 +1,5 @@
+---
+"@hyperdx/api": patch
+---
+
+Disable mongoose autoCreate in check-alerts worker to prevent NamespaceExists error spans on mongodb.create

packages/api/src/tasks/checkAlerts/providers/__tests__/default.test.ts

@@ -0,0 +1,27 @@
+import * as models from '@/models';
+import DefaultAlertProvider from '@/tasks/checkAlerts/providers/default';
+
+jest.mock('@/models', () => ({
+  ...jest.requireActual('@/models'),
+  connectDB: jest.fn().mockResolvedValue(undefined),
+  mongooseConnection: {
+    close: jest.fn().mockResolvedValue(undefined),
+  },
+}));
+
+describe('DefaultAlertProvider.init', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('disables both autoIndex and autoCreate when connecting to MongoDB', async () => {
+    const provider = new DefaultAlertProvider();
+    await provider.init();
+
+    expect(models.connectDB).toHaveBeenCalledTimes(1);
+    expect(models.connectDB).toHaveBeenCalledWith({
+      autoIndex: false,
+      autoCreate: false,
+    });
+  });
+});

packages/api/src/tasks/checkAlerts/providers/default.ts

@@ -409,12 +409,15 @@ async function loadAlert(
 
 export default class DefaultAlertProvider implements AlertProvider {
   async init() {
-    // The check-alerts worker only reads from MongoDB and never needs to
-    // ensure indexes exist (the API service owns that). Disabling autoIndex
-    // prevents background createIndexes calls from racing the short-lived
-    // connection close (which sends endSessions), surfaced as
-    // MongoExpiredSessionError on mongodb.createIndexes spans.
-    await Promise.all([connectDB({ autoIndex: false })]);
+    // The check-alerts worker only reads/writes existing collections in MongoDB
+    // and never needs to ensure indexes or collections exist (the API service
+    // owns the schema). Disabling autoIndex prevents background createIndexes
+    // calls from racing the short-lived connection close (which sends
+    // endSessions), surfaced as MongoExpiredSessionError on
+    // mongodb.createIndexes spans. Disabling autoCreate prevents Model.init()
+    // from calling createCollection for each model on every run, which
+    // otherwise records failed mongodb.create (NamespaceExists) spans.
+    await Promise.all([connectDB({ autoIndex: false, autoCreate: false })]);
   }
 
   async asyncDispose() {