修复问题3

server.js

@@ -392,6 +392,8 @@ const ensureSourceCached = async ({ s3Client, bucket, key, targetPath, onProgres
         const s3Stream = response.Body;
         const totalBytes = response.ContentLength || 0;
         let downloadedBytes = 0;
+        let lastLoggedPercent = -1;
+        let lastLoggedBytes = 0;
 
         logger.log(`[download] response received bucket=${bucket} key=${key} totalBytes=${totalBytes || 0}`);
 
@@ -403,6 +405,14 @@ const ensureSourceCached = async ({ s3Client, bucket, key, targetPath, onProgres
             const writeStream = fs.createWriteStream(targetPath);
             s3Stream.on('data', (chunk) => {
                 downloadedBytes += chunk.length;
+                const percent = totalBytes ? Math.min(100, Math.round((downloadedBytes / totalBytes) * 100)) : 0;
+                const shouldLogPercent = totalBytes && percent >= lastLoggedPercent + 5;
+                const shouldLogBytes = !totalBytes && downloadedBytes >= lastLoggedBytes + (5 * 1024 * 1024);
+                if (shouldLogPercent || shouldLogBytes) {
+                    logger.log(`[download] progress bucket=${bucket} key=${key} downloadedBytes=${downloadedBytes} totalBytes=${totalBytes || 0} percent=${percent}`);
+                    lastLoggedPercent = percent;
+                    lastLoggedBytes = downloadedBytes;
+                }
                 if (typeof onProgress === 'function') {
                     onProgress({ totalBytes, downloadedBytes, cacheExists: false });
                 }