feat(fastify): Update scope transactionName when handling request (#11447)

This PR updates the isolation scope's `transactionName` by adding another
hook callback in our `setupFastifyErrorHandler` fastify plugin. This is
better than accessing the otel span for two reasons:

1. We can always update the transactionName, not just when a span is
sampled and recording
2. The `onRequest` hook is executed earlier in the lifecycle than the
`preHandler` hook that Otel uses to trigger the `requestHook` callback.

Author: Lms24

dev-packages/e2e-tests/test-applications/node-fastify-app/src/app.js

@@ -55,8 +55,8 @@ app.get('/test-error', async function (req, res) {
   res.send({ exceptionId });
 });
 
-app.get('/test-exception', async function (req, res) {
-  throw new Error('This is an exception');
+app.get('/test-exception/:id', async function (req, res) {
+  throw new Error(`This is an exception with id ${req.params.id}`);
 });
 
 app.get('/test-outgoing-fetch-external-allowed', async function (req, res) {

dev-packages/e2e-tests/test-applications/node-fastify-app/tests/errors.test.ts

@@ -41,28 +41,28 @@ test('Sends exception to Sentry', async ({ baseURL }) => {
 
 test('Sends correct error event', async ({ baseURL }) => {
   const errorEventPromise = waitForError('node-fastify-app', event => {
-    return !event.type && event.exception?.values?.[0]?.value === 'This is an exception';
+    return !event.type && event.exception?.values?.[0]?.value === 'This is an exception with id 123';
   });
 
   try {
-    await axios.get(`${baseURL}/test-exception`);
+    await axios.get(`${baseURL}/test-exception/123`);
   } catch {
     // this results in an error, but we don't care - we want to check the error event
   }
 
   const errorEvent = await errorEventPromise;
 
   expect(errorEvent.exception?.values).toHaveLength(1);
-  expect(errorEvent.exception?.values?.[0]?.value).toBe('This is an exception');
+  expect(errorEvent.exception?.values?.[0]?.value).toBe('This is an exception with id 123');
 
   expect(errorEvent.request).toEqual({
     method: 'GET',
     cookies: {},
     headers: expect.any(Object),
-    url: 'http://localhost:3030/test-exception',
+    url: 'http://localhost:3030/test-exception/123',
   });
 
-  expect(errorEvent.transaction).toEqual('GET /test-exception');
+  expect(errorEvent.transaction).toEqual('GET /test-exception/:id');
 
   expect(errorEvent.contexts?.trace).toEqual({
     trace_id: expect.any(String),

dev-packages/e2e-tests/test-applications/node-fastify-app/tests/transactions.test.ts

@@ -56,6 +56,23 @@ test('Sends an API route transaction', async ({ baseURL }) => {
   expect(transactionEvent).toEqual(
     expect.objectContaining({
       spans: [
+        {
+          data: {
+            'plugin.name': 'fastify -> sentry-fastify-error-handler',
+            'fastify.type': 'middleware',
+            'hook.name': 'onRequest',
+            'otel.kind': 'INTERNAL',
+            'sentry.origin': 'manual',
+          },
+          description: 'middleware - fastify -> sentry-fastify-error-handler',
+          parent_span_id: expect.any(String),
+          span_id: expect.any(String),
+          start_timestamp: expect.any(Number),
+          status: 'ok',
+          timestamp: expect.any(Number),
+          trace_id: expect.any(String),
+          origin: 'manual',
+        },
         {
           data: {
             'plugin.name': 'fastify -> sentry-fastify-error-handler',

packages/node/src/integrations/tracing/fastify.ts

@@ -1,6 +1,6 @@
 import { registerInstrumentations } from '@opentelemetry/instrumentation';
 import { FastifyInstrumentation } from '@opentelemetry/instrumentation-fastify';
-import { captureException, defineIntegration } from '@sentry/core';
+import { captureException, defineIntegration, getIsolationScope } from '@sentry/core';
 import type { IntegrationFn } from '@sentry/types';
 
 import { addOriginToSpan } from '../../utils/addOriginToSpan';
@@ -35,6 +35,19 @@ interface Fastify {
   addHook: (hook: string, handler: (request: unknown, reply: unknown, error: Error) => void) => void;
 }
 
+/**
+ * Minimal request type containing properties around route information.
+ * Works for Fastify 3, 4 and presumably 5.
+ */
+interface FastifyRequestRouteInfo {
+  // since [email protected]
+  routeOptions?: {
+    url?: string;
+    method?: string;
+  };
+  routerPath?: string;
+}
+
 /**
  * Setup an error handler for Fastify.
  */
@@ -45,6 +58,20 @@ export function setupFastifyErrorHandler(fastify: Fastify): void {
         captureException(error);
       });
 
+      // registering `onRequest` hook here instead of using Otel `onRequest` callback b/c `onRequest` hook
+      // is ironically called in the fastify `preHandler` hook which is called later in the lifecycle:
+      // https://fastify.dev/docs/latest/Reference/Lifecycle/
+      fastify.addHook('onRequest', async (request, _reply) => {
+        const reqWithRouteInfo = request as FastifyRequestRouteInfo;
+
+        // Taken from Otel Fastify instrumentation:
+        // https://github.com/open-telemetry/opentelemetry-js-contrib/blob/main/plugins/node/opentelemetry-instrumentation-fastify/src/instrumentation.ts#L94-L96
+        const routeName = reqWithRouteInfo.routeOptions?.url || reqWithRouteInfo.routerPath;
+        const method = reqWithRouteInfo.routeOptions?.method || 'GET';
+
+        getIsolationScope().setTransactionName(`${method} ${routeName}`);
+      });
+
       done();
     },
     {