ref(nextjs): Make Pages Router API Routes instrumentation OTEL ready (#13904)

Drop all spans/transactions emitted by Next.js for pages router API
routes because they are currently super buggy with wrong timestamps. Fix
pending: vercel/next.js#70908

This is just a bit of prep-work so we can at some point disable the
logic where we turn on all Next.js spans and still have high quality
data.

Author: Luca Forstner

packages/nextjs/src/common/pages-router-instrumentation/wrapApiHandlerWithSentry.ts

@@ -2,13 +2,16 @@ import {
   SEMANTIC_ATTRIBUTE_SENTRY_SOURCE,
   captureException,
   continueTrace,
+  getActiveSpan,
+  getRootSpan,
   setHttpStatus,
   startSpanManual,
   withIsolationScope,
 } from '@sentry/core';
 import { consoleSandbox, isString, logger, objectify } from '@sentry/utils';
 
 import { SEMANTIC_ATTRIBUTE_SENTRY_ORIGIN } from '@sentry/core';
+import { TRANSACTION_ATTR_SHOULD_DROP_TRANSACTION } from '../span-attributes-with-logic-attached';
 import type { AugmentedNextApiRequest, AugmentedNextApiResponse, NextApiHandler } from '../types';
 import { flushSafelyWithTimeout } from '../utils/responseEnd';
 import { escapeNextjsTracing } from '../utils/tracingUtils';
@@ -24,6 +27,15 @@ import { vercelWaitUntil } from '../utils/vercelWaitUntil';
  * @returns The wrapped handler
  */
 export function wrapApiHandlerWithSentry(apiHandler: NextApiHandler, parameterizedRoute: string): NextApiHandler {
+  // Since the API route handler spans emitted by Next.js are super buggy with completely wrong timestamps
+  // (fix pending at the time of writing this: https://github.com/vercel/next.js/pull/70908) we want to intentionally
+  // drop them. In the future, when Next.js' OTEL instrumentation is in a high-quality place we can potentially think
+  // about keeping them.
+  const nextJsOwnedSpan = getActiveSpan();
+  if (nextJsOwnedSpan) {
+    getRootSpan(nextJsOwnedSpan)?.setAttribute(TRANSACTION_ATTR_SHOULD_DROP_TRANSACTION, true);
+  }
+
   return new Proxy(apiHandler, {
     apply: (
       wrappingTarget,

packages/nextjs/src/common/span-attributes-with-logic-attached.ts

@@ -0,0 +1,4 @@
+/**
+ * If this attribute is attached to a transaction, the Next.js SDK will drop that transaction.
+ */
+export const TRANSACTION_ATTR_SHOULD_DROP_TRANSACTION = 'sentry.drop_transaction';

packages/nextjs/src/server/index.ts

@@ -21,6 +21,7 @@ import type { EventProcessor } from '@sentry/types';
 import { DEBUG_BUILD } from '../common/debug-build';
 import { devErrorSymbolicationEventProcessor } from '../common/devErrorSymbolicationEventProcessor';
 import { getVercelEnv } from '../common/getVercelEnv';
+import { TRANSACTION_ATTR_SHOULD_DROP_TRANSACTION } from '../common/span-attributes-with-logic-attached';
 import { isBuild } from '../common/utils/isBuild';
 import { distDirRewriteFramesIntegration } from './distDirRewriteFramesIntegration';
 
@@ -249,6 +250,11 @@ export function init(options: NodeOptions): NodeClient | undefined {
             return null;
           }
 
+          // Filter transactions that we explicitly want to drop.
+          if (event.contexts?.trace?.data?.[TRANSACTION_ATTR_SHOULD_DROP_TRANSACTION]) {
+            return null;
+          }
+
           return event;
         } else {
           return event;