[Chore] eliminate duplicated and unconditional object serialization in...

[Chore] eliminate duplicated and unconditional object serialization in anthropic messages api (#27792)
Signed-off-by: Vico Chu <vico24826@gmail.com>

vllm/entrypoints/anthropic/serving_messages.py

@@ -231,9 +231,11 @@ class AnthropicServingMessages(OpenAIServingChat):
         See https://docs.anthropic.com/en/api/messages
         for the API specification. This API mimics the Anthropic messages API.
         """
+        if logger.isEnabledFor(logging.DEBUG):
             logger.debug("Received messages request %s", request.model_dump_json())
         chat_req = self._convert_anthropic_to_openai_request(request)
-        logger.debug("Convert to OpenAI request %s", request.model_dump_json())
+        if logger.isEnabledFor(logging.DEBUG):
+            logger.debug("Convert to OpenAI request %s", chat_req.model_dump_json())
         generator = await self.create_chat_completion(chat_req, raw_request)
 
         if isinstance(generator, ErrorResponse):

vllm/entrypoints/openai/api_server.py

@@ -648,10 +648,9 @@ async def create_messages(request: AnthropicMessagesRequest, raw_request: Reques
         return translate_error_response(generator)
 
     elif isinstance(generator, AnthropicMessagesResponse):
-        logger.debug(
-            "Anthropic Messages Response: %s", generator.model_dump(exclude_none=True)
-        )
-        return JSONResponse(content=generator.model_dump(exclude_none=True))
+        resp = generator.model_dump(exclude_none=True)
+        logger.debug("Anthropic Messages Response: %s", resp)
+        return JSONResponse(content=resp)
 
     return StreamingResponse(content=generator, media_type="text/event-stream")