fix(nextjs): Stop sending transactions for requests that 404 (#4095)

packages/nextjs/src/index.client.ts

@@ -30,6 +30,7 @@ export function init(options: NextjsOptions): void {
   });
   configureScope(scope => {
     scope.setTag('runtime', 'browser');
+    scope.addEventProcessor(event => (event.type === 'transaction' && event.transaction === '/404' ? null : event));
   });
 }
 

packages/nextjs/src/index.server.ts

@@ -1,6 +1,7 @@
 import { Carrier, getHubFromCarrier, getMainCarrier } from '@sentry/hub';
 import { RewriteFrames } from '@sentry/integrations';
 import { configureScope, getCurrentHub, init as nodeInit, Integrations } from '@sentry/node';
+import { Event } from '@sentry/types';
 import { escapeStringForRegex, logger } from '@sentry/utils';
 import * as domainModule from 'domain';
 import * as path from 'path';
@@ -56,6 +57,8 @@ export function init(options: NextjsOptions): void {
     if (process.env.VERCEL) {
       scope.setTag('vercel', true);
     }
+
+    scope.addEventProcessor(filterTransactions);
   });
 
   if (activeDomain) {
@@ -65,6 +68,8 @@ export function init(options: NextjsOptions): void {
     // apply the changes made by `nodeInit` to the domain's hub also
     domainHub.bindClient(globalHub.getClient());
     domainHub.getScope()?.update(globalHub.getScope());
+    // `scope.update()` doesn’t copy over event processors, so we have to add it manually
+    domainHub.getScope()?.addEventProcessor(filterTransactions);
 
     // restore the domain hub as the current one
     domain.active = activeDomain;
@@ -107,6 +112,10 @@ function addServerIntegrations(options: NextjsOptions): void {
   }
 }
 
+function filterTransactions(event: Event): Event | null {
+  return event.type === 'transaction' && event.transaction === '/404' ? null : event;
+}
+
 export { withSentryConfig } from './config';
 export { withSentry } from './utils/withSentry';
 

packages/nextjs/test/index.client.test.ts

@@ -1,8 +1,9 @@
+import { BaseClient } from '@sentry/core';
 import { getCurrentHub } from '@sentry/hub';
 import * as SentryReact from '@sentry/react';
 import { Integrations as TracingIntegrations } from '@sentry/tracing';
 import { Integration } from '@sentry/types';
-import { getGlobalObject } from '@sentry/utils';
+import { getGlobalObject, logger, SentryError } from '@sentry/utils';
 
 import { init, Integrations, nextRouterInstrumentation } from '../src/index.client';
 import { NextjsOptions } from '../src/utils/nextjsOptions';
@@ -12,10 +13,12 @@ const { BrowserTracing } = TracingIntegrations;
 const global = getGlobalObject();
 
 const reactInit = jest.spyOn(SentryReact, 'init');
+const captureEvent = jest.spyOn(BaseClient.prototype, 'captureEvent');
+const logError = jest.spyOn(logger, 'error');
 
 describe('Client init()', () => {
   afterEach(() => {
-    reactInit.mockClear();
+    jest.clearAllMocks();
     global.__SENTRY__.hub = undefined;
   });
 
@@ -50,6 +53,22 @@ describe('Client init()', () => {
     expect(currentScope._tags).toEqual({ runtime: 'browser' });
   });
 
+  it('adds 404 transaction filter', () => {
+    init({
+      dsn: 'https://dogsarebadatkeepingsecrets@squirrelchasers.ingest.sentry.io/12312012',
+      tracesSampleRate: 1.0,
+    });
+    const hub = getCurrentHub();
+    const sendEvent = jest.spyOn(hub.getClient()!.getTransport!(), 'sendEvent');
+
+    const transaction = hub.startTransaction({ name: '/404' });
+    transaction.finish();
+
+    expect(sendEvent).not.toHaveBeenCalled();
+    expect(captureEvent.mock.results[0].value).toBeUndefined();
+    expect(logError).toHaveBeenCalledWith(new SentryError('An event processor returned null, will not send event.'));
+  });
+
   describe('integrations', () => {
     it('does not add BrowserTracing integration by default if tracesSampleRate is not set', () => {
       init({});

packages/nextjs/test/index.server.test.ts

@@ -1,8 +1,9 @@
+import { BaseClient } from '@sentry/core';
 import { RewriteFrames } from '@sentry/integrations';
 import * as SentryNode from '@sentry/node';
 import { getCurrentHub, NodeClient } from '@sentry/node';
 import { Integration } from '@sentry/types';
-import { getGlobalObject } from '@sentry/utils';
+import { getGlobalObject, logger, SentryError } from '@sentry/utils';
 import * as domain from 'domain';
 
 import { init } from '../src/index.server';
@@ -16,10 +17,12 @@ const global = getGlobalObject();
 (global as typeof global & { __rewriteFramesDistDir__: string }).__rewriteFramesDistDir__ = '.next';
 
 const nodeInit = jest.spyOn(SentryNode, 'init');
+const captureEvent = jest.spyOn(BaseClient.prototype, 'captureEvent');
+const logError = jest.spyOn(logger, 'error');
 
 describe('Server init()', () => {
   afterEach(() => {
-    nodeInit.mockClear();
+    jest.clearAllMocks();
     global.__SENTRY__.hub = undefined;
   });
 
@@ -87,6 +90,22 @@ describe('Server init()', () => {
     expect(currentScope._tags.vercel).toBeUndefined();
   });
 
+  it('adds 404 transaction filter', () => {
+    init({
+      dsn: 'https://dogsarebadatkeepingsecrets@squirrelchasers.ingest.sentry.io/12312012',
+      tracesSampleRate: 1.0,
+    });
+    const hub = getCurrentHub();
+    const sendEvent = jest.spyOn(hub.getClient()!.getTransport!(), 'sendEvent');
+
+    const transaction = hub.startTransaction({ name: '/404' });
+    transaction.finish();
+
+    expect(sendEvent).not.toHaveBeenCalled();
+    expect(captureEvent.mock.results[0].value).toBeUndefined();
+    expect(logError).toHaveBeenCalledWith(new SentryError('An event processor returned null, will not send event.'));
+  });
+
   it("initializes both global hub and domain hub when there's an active domain", () => {
     const globalHub = getCurrentHub();
     const local = domain.create();