refactor replica _handle_errors_and_metrics (#51644)

Signed-off-by: Abrar Sheikh <abrar@anyscale.com>

Author: abrarsheikh

python/ray/serve/_private/replica.py

@@ -483,20 +483,36 @@ def _status_code_callback(s: str):
             self._metrics_manager.dec_num_ongoing_requests()
 
         latency_ms = (time.time() - start_time) * 1000
+        self._record_errors_and_metrics(
+            user_exception, status_code, latency_ms, request_metadata, request_args
+        )
+
+        if user_exception is not None:
+            raise user_exception from None
+
+    def _record_errors_and_metrics(
+        self,
+        user_exception: Optional[BaseException],
+        status_code: Optional[str],
+        latency_ms: float,
+        request_metadata: RequestMetadata,
+        request_args: Tuple[Any],
+    ):
+        http_method = self._maybe_get_http_method(request_metadata, request_args)
+        http_route = request_metadata.route
+        call_method = request_metadata.call_method
         if user_exception is None:
             status_str = "OK"
         elif isinstance(user_exception, asyncio.CancelledError):
             status_str = "CANCELLED"
         else:
             status_str = "ERROR"
 
-        http_method = self._maybe_get_http_method(request_metadata, request_args)
-        http_route = request_metadata.route
         # Set in _wrap_user_method_call.
         logger.info(
             access_log_msg(
                 method=http_method or "CALL",
-                route=http_route or request_metadata.call_method,
+                route=http_route or call_method,
                 # Prefer the HTTP status code if it was populated.
                 status=status_code or status_str,
                 latency_ms=latency_ms,
@@ -509,9 +525,6 @@ def _status_code_callback(s: str):
             was_error=user_exception is not None,
         )
 
-        if user_exception is not None:
-            raise user_exception from None
-
     async def _call_user_generator(
         self,
         request_metadata: RequestMetadata,