fix: memory usage for thumbnail generation

packages/nocodb/src/modules/jobs/jobs/thumbnail-generator/thumbnail-generator.processor.ts

@@ -16,17 +16,24 @@ export class ThumbnailGeneratorProcessor {
   async job(job: Job<ThumbnailGeneratorJobData>) {
     const { attachments } = job.data;
 
-    const thumbnailPromises = attachments.map(async (attachment) => {
+    const results = [];
+
+    for (const attachment of attachments) {
       const thumbnail = await this.generateThumbnail(attachment);
-      return {
+
+      if (!thumbnail) {
+        continue;
+      }
+
+      results.push({
         path: attachment.path ?? attachment.url,
         card_cover: thumbnail?.card_cover,
         small: thumbnail?.small,
         tiny: thumbnail?.tiny,
-      };
       });
+    }
 
-    return await Promise.all(thumbnailPromises);
+    return results;
   }
 
   private async generateThumbnail(
@@ -47,6 +54,8 @@ export class ThumbnailGeneratorProcessor {
       return;
     }
 
+    sharp.concurrency(1);
+
     try {
       const storageAdapter = await NcPluginMgrv2.storageAdapter();
 
@@ -66,8 +75,11 @@ export class ThumbnailGeneratorProcessor {
         tiny: path.join('nc', 'thumbnails', relativePath, 'tiny.jpg'),
       };
 
-      await Promise.all(
-        Object.entries(thumbnailPaths).map(async ([size, thumbnailPath]) => {
+      const sharpImage = await sharp(file, {
+        limitInputPixels: false,
+      });
+
+      for (const [size, thumbnailPath] of Object.entries(thumbnailPaths)) {
         let height;
         switch (size) {
           case 'card_cover':
@@ -84,9 +96,7 @@ export class ThumbnailGeneratorProcessor {
             break;
         }
 
-          const resizedImage = await sharp(file, {
-            limitInputPixels: false,
-          })
+        const resizedImage = await sharpImage
           .resize(undefined, height, {
             fit: sharp.fit.cover,
             kernel: 'lanczos3',
@@ -100,8 +110,7 @@ export class ThumbnailGeneratorProcessor {
             mimetype: 'image/jpeg',
           },
         );
-        }),
-      );
+      }
 
       return thumbnailPaths;
     } catch (error) {