Improve media cleanup performance with bounded concurrency and aggregated failure reporting

app/api/comments/[commentId]/route.ts

@@ -8,6 +8,9 @@ import { validateShareLinkAccess } from '@/lib/share-links';
 import { getShareSessionFromRequest } from '@/lib/share-session';
 import { apiErrors, successResponse, withCacheControl } from '@/lib/api-response';
 import { getGuestIdentityFromRequest } from '@/lib/guest-identity';
+import { runWithConcurrency } from '@/lib/async-pool';
+
+const CLEANUP_DELETE_CONCURRENCY = 5;
 
 type RouteParams = { params: Promise<{ commentId: string }> };
 
@@ -298,30 +301,31 @@ export async function DELETE(request: NextRequest, { params }: RouteParams) {
         // Clean up media files from R2 (best-effort, don't block on failure)
         const AUDIO_PREFIX = '/api/upload/audio/';
         const IMAGE_PREFIX = '/api/upload/image/';
-        for (const url of mediaUrls) {
-            try {
+        const mediaKeys = [...new Set(mediaUrls.map((url) => {
             // Extract filename using string parsing (safe against ReDoS)
-                let key: string | null = null;
             if (url.includes(AUDIO_PREFIX)) {
                 const filename = url.slice(url.indexOf(AUDIO_PREFIX) + AUDIO_PREFIX.length);
-                    if (filename) key = `voice/${filename}`;
-                } else if (url.includes(IMAGE_PREFIX)) {
-                    const filename = url.slice(url.indexOf(IMAGE_PREFIX) + IMAGE_PREFIX.length);
-                    if (filename) key = `images/${filename}`;
+                return filename ? `voice/${filename}` : null;
             }
+            if (url.includes(IMAGE_PREFIX)) {
+                const filename = url.slice(url.indexOf(IMAGE_PREFIX) + IMAGE_PREFIX.length);
+                return filename ? `images/${filename}` : null;
+            }
+            return null;
+        }).filter((key): key is string => Boolean(key)))];
 
-                if (key) {
+        await runWithConcurrency(mediaKeys, CLEANUP_DELETE_CONCURRENCY, async (key) => {
+            try {
                 await r2Client.send(
                     new DeleteObjectCommand({
                         Bucket: R2_BUCKET_NAME,
                         Key: key,
                     })
                 );
-                }
             } catch (err) {
-                console.error('Failed to delete audio from R2:', err);
-            }
+                console.error(`Failed to delete media from R2 (key: ${key}):`, err);
             }
+        });
 
         const response = successResponse({ message: 'Comment deleted' });
         return withCacheControl(response, 'private, no-store');

lib/async-pool.ts

@@ -0,0 +1,29 @@
+/**
+ * Execute async work with a bounded number of in-flight tasks.
+ */
+export async function runWithConcurrency<T>(
+  items: T[],
+  limit: number,
+  worker: (item: T) => Promise<void>
+): Promise<void> {
+  if (items.length === 0) return;
+
+  const concurrency = Math.max(1, Math.floor(limit));
+  let nextIndex = 0;
+
+  async function runWorker(): Promise<void> {
+    while (true) {
+      const currentIndex = nextIndex;
+      nextIndex += 1;
+
+      if (currentIndex >= items.length) {
+        return;
+      }
+
+      await worker(items[currentIndex]);
+    }
+  }
+
+  const workerCount = Math.min(concurrency, items.length);
+  await Promise.all(Array.from({ length: workerCount }, () => runWorker()));
+}

lib/bunny-stream-cleanup.ts

@@ -1,3 +1,5 @@
+import { runWithConcurrency } from '@/lib/async-pool';
+
 interface BunnyVideoRef {
   providerId: string;
   videoId: string;
@@ -5,6 +7,7 @@ interface BunnyVideoRef {
 
 const BUNNY_API_BASE = 'https://video.bunnycdn.com';
 const BUNNY_VIDEO_ID_PATTERN = /^[A-Za-z0-9_-]{8,128}$/;
+const BUNNY_DELETE_CONCURRENCY = 5;
 
 function getBunnyConfig(): { apiKey: string; libraryId: string } {
   const apiKey = process.env.BUNNY_STREAM_API_KEY;
@@ -33,8 +36,9 @@ export async function cleanupBunnyStreamVideos(videoRefs: BunnyVideoRef[]): Prom
   if (bunnyVideoIds.length === 0) return;
 
   const { apiKey, libraryId } = getBunnyConfig();
+  const failures: Array<{ videoId: string; status: number; bodySnippet: string }> = [];
 
-  for (const bunnyVideoId of bunnyVideoIds) {
+  await runWithConcurrency(bunnyVideoIds, BUNNY_DELETE_CONCURRENCY, async (bunnyVideoId) => {
     const response = await fetch(`${BUNNY_API_BASE}/library/${libraryId}/videos/${encodeURIComponent(bunnyVideoId)}`, {
       method: 'DELETE',
       headers: {
@@ -43,13 +47,23 @@ export async function cleanupBunnyStreamVideos(videoRefs: BunnyVideoRef[]): Prom
     });
 
     // Treat not-found as already deleted.
-    if (response.status === 404) continue;
+    if (response.status === 404) return;
 
     if (!response.ok) {
       const body = await response.text().catch(() => '');
-      throw new Error(
-        `Bunny cleanup failed for video ${bunnyVideoId}: ${response.status} ${body.slice(0, 300)}`
-      );
+      failures.push({
+        videoId: bunnyVideoId,
+        status: response.status,
+        bodySnippet: body.slice(0, 300),
+      });
     }
+  });
+
+  if (failures.length > 0) {
+    const preview = failures
+      .slice(0, 3)
+      .map((failure) => `${failure.videoId} (${failure.status})`)
+      .join(', ');
+    throw new Error(`Bunny cleanup failed for ${failures.length} video(s): ${preview}`);
   }
 }

lib/r2-cleanup.ts

@@ -1,11 +1,13 @@
 import { DeleteObjectCommand } from '@aws-sdk/client-s3';
 import { r2Client, R2_BUCKET_NAME } from '@/lib/r2';
 import { db } from '@/lib/db';
+import { runWithConcurrency } from '@/lib/async-pool';
 
 /** The path prefix for images served by the upload API. */
 const IMAGE_PATH_PREFIX = '/api/upload/image/';
 /** The path prefix for audio URLs served by the upload API. */
 const AUDIO_PATH_PREFIX = '/api/upload/audio/';
+const CLEANUP_DELETE_CONCURRENCY = 5;
 
 /**
  * Extract the R2 object key from a media URL.
@@ -26,18 +28,17 @@ function mediaUrlToKey(url: string): string | null {
  * Delete a list of media files from R2 (best-effort, logs failures).
  */
 async function deleteMediaFiles(mediaUrls: string[]) {
-    for (const url of mediaUrls) {
+    const mediaKeys = [...new Set(mediaUrls.map(mediaUrlToKey).filter((key): key is string => Boolean(key)))];
+
+    await runWithConcurrency(mediaKeys, CLEANUP_DELETE_CONCURRENCY, async (key) => {
         try {
-            const key = mediaUrlToKey(url);
-            if (key) {
             await r2Client.send(
                 new DeleteObjectCommand({ Bucket: R2_BUCKET_NAME, Key: key })
             );
-            }
         } catch (err) {
-            console.error('Failed to delete media from R2:', err);
-        }
+            console.error(`Failed to delete media from R2 (key: ${key}):`, err);
         }
+    });
 }
 
 /**