improve: explicitly use after

Author: ben-fornefeld

src/instrumentation/span-processor.ts

@@ -1,12 +1,11 @@
 import type { Attributes, Context, TextMapGetter } from '@opentelemetry/api'
-import { diag, SpanKind } from '@opentelemetry/api'
+import { diag, SpanKind, TraceFlags } from '@opentelemetry/api'
 import type {
   ReadableSpan,
   Span,
   SpanProcessor,
 } from '@opentelemetry/sdk-trace-base'
-
-import { TraceFlags } from '@opentelemetry/api'
+import { after } from 'next/server'
 
 type AttributesFromHeaderFunc = <Carrier = unknown>(
   headers: Carrier,
@@ -15,41 +14,6 @@ type AttributesFromHeaderFunc = <Carrier = unknown>(
 
 type AttributesFromHeaders = Record<string, string> | AttributesFromHeaderFunc
 
-/**
- * Helper ────────────────────────────────────────────────────────────────────
- * Try to obtain the callback that extends the lifetime of the request so that
- * our exporter has time to flush.
- *
- * Priority:
- *   1. `after(cb)`   (Next.js 15)
- *   2. fallback      (best-effort `setTimeout`)
- */
-function scheduleAfterResponse(task: () => Promise<void>) {
-  try {
-    // avoid a hard dependency so this file can be imported outside a route.
-    // `require` is evaluated lazily – if Next isn't around it will throw.
-    // eslint-disable-next-line
-    const mod = require('next/server') as { after?: (cb: () => void) => void }
-
-    if (typeof mod.after === 'function') {
-      mod.after(() => {
-        // no await – Next treats sync or async the same,
-        // we just fire the promise and let it resolve.
-        void task()
-      })
-      return
-    }
-  } catch {
-    /* ignored – we're probably not inside a Next context */
-  }
-
-  // 2.  Node / local fallback – try our best and hope the
-  //     process stays alive long enough.
-  setTimeout(() => {
-    void task()
-  }, 0)
-}
-
 function isSampled(traceFlags: number): boolean {
   // Use bitwise AND to inspect the sampled flag
   return (traceFlags & TraceFlags.SAMPLED) !== 0
@@ -113,7 +77,7 @@ export class NextCompositeSpanProcessor implements SpanProcessor {
     // Attach request-specific attributes only on the root span
     if (isRoot && isSampled(traceFlags)) {
       // When the *response* (or prerender) is done, flush traces.
-      scheduleAfterResponse(async () => {
+      after(async () => {
         if (this.rootSpanIds.has(traceId)) {
           // Root hasn’t finished yet – wait via onEnd().
           const waiter = new Promise<void>((resolve) =>