hotfix/add error handle in pd routing

Signed-off-by: Rui Zhang <[email protected]>

Author: zerofishnoodles

src/vllm_router/services/request_service/request.py

@@ -336,12 +336,39 @@ async def send_request_to_decode(
         "X-Request-Id": request_id,
     }
 
-    async with client.stream(
-        "POST", endpoint, json=req_data, headers=headers
-    ) as response:
-        response.raise_for_status()
-        async for chunk in response.aiter_bytes():
-            yield chunk
+    try:
+        async with client.stream(
+            "POST", endpoint, json=req_data, headers=headers
+        ) as response:
+            response.raise_for_status()
+            async for chunk in response.aiter_bytes():
+                yield chunk
+    except httpx.HTTPStatusError as e:
+        logger.error(f"HTTP error in decode request: {e}", exc_info=True)
+        try:
+            error_text = e.response.text
+        except Exception:
+            error_text = f"HTTP {e.response.status_code}"
+        # Yield error as JSON response
+        error_response = {
+            "error": {
+                "message": f"Backend error: {error_text}",
+                "type": "backend_error",
+                "code": e.response.status_code,
+            }
+        }
+        yield json.dumps(error_response).encode("utf-8")
+    except Exception as e:
+        logger.error(f"Unexpected error in decode request: {e}", exc_info=True)
+        # Yield error as JSON response
+        error_response = {
+            "error": {
+                "message": f"Internal server error: {str(e)}",
+                "type": "internal_error",
+                "code": 500,
+            }
+        }
+        yield json.dumps(error_response).encode("utf-8")
 
 
 async def route_disaggregated_prefill_request(