added retry logic for object storage download failures

apps/webapp/app/v3/r2.server.ts

@@ -93,11 +93,39 @@ export async function downloadPacketFromObjectStore(
 
     logger.debug("Downloading from object store", { url: url.href });
 
-    const response = await r2.fetch(url.toString());
+    async function fetchWithRetry(url:string,retries =3,delay=500):Promise<Response>{
+
+       if (!r2) {
+      throw new Error("Object store credentials are not set");
+    }
+
+       for(let attempt =1; attempt<=retries;attempt++){
+        try {
+          const response = await r2.fetch(url);
+          if(response.ok) return response;
+
+          // only retry on transient server/network errors
+         if(response.status >= 500 && response.status<600 ){
+          throw new Error(`Server Error : ${response.statusText}`);
+         }
+
+         // for other non server errors 
+         throw new Error(`non-retryable error :${response.statusText}`);
+
+        } catch (error:any) {
+          if(attempt == retries) throw error;
+          logger.warn(`Retrying object Download (attempt: ${attempt}) out of ${retries}`,{
+            url,
+            error:error.message,
+          });
+          await new Promise((res)=>setTimeout(res,delay*attempt));
+        }
+       }
+
+       throw new Error(`Failed to fetch ${url} after ${retries} retries`);
 
-    if (!response.ok) {
-      throw new Error(`Failed to download input from ${url}: ${response.statusText}`);
     }
+    const response = await fetchWithRetry(url.toString());
 
     const data = await response.text();