feat: add langfuse openai SDK tracing to openai_provider only

src/qwenpaw/providers/openai_provider.py

@@ -3,13 +3,15 @@
 
 from __future__ import annotations
 
+import importlib.util
 import json
 import logging
+import os
 import time
 from typing import TYPE_CHECKING, Any, List
 
 from agentscope.model import ChatModelBase
-from openai import APIError, AsyncOpenAI
+from openai import APIError
 
 from qwenpaw.providers.provider import ModelInfo, Provider
 
@@ -21,6 +23,16 @@
 DASHSCOPE_BASE_URL = "https://dashscope.aliyuncs.com/compatible-mode/v1"
 CODING_DASHSCOPE_BASE_URL = "https://coding.dashscope.aliyuncs.com/v1"
 
+if os.environ.get("LANGFUSE_SECRET_KEY") and importlib.util.find_spec("langfuse"):
+    from langfuse.openai import AsyncOpenAI  # type: ignore[import]
+else:
+    if os.environ.get("LANGFUSE_SECRET_KEY"):
+        logger.warning(
+            "LANGFUSE_SECRET_KEY is set but langfuse is not installed; "
+            "install with `pip install langfuse` to enable tracing"
+        )
+    from openai import AsyncOpenAI
+
 
 class OpenAIProvider(Provider):
     """Provider implementation for OpenAI API and compatible endpoints."""