Update feedback enabled endpoint (#332)

Update feedback endabled endpoint behavior

langserve/api_handler.py

@@ -439,8 +439,8 @@ def __init__(
                 including events that occurred on the server side.
                 Be sure not to include any sensitive information in the callback events.
             enable_feedback_endpoint: Whether to enable an endpoint for logging feedback
-                to LangSmith. Enabled by default. If this flag is disabled or LangSmith
-                tracing is not enabled for the runnable, then 400 errors will be thrown
+                to LangSmith. Disabled by default. If this flag is disabled or LangSmith
+                tracing is not enabled for the runnable, then 4xx errors will be thrown
                 when accessing the feedback endpoint
             per_req_config_modifier: optional function that can be used to update the
                 RunnableConfig for a given run based on the raw request. This is useful,
@@ -1070,15 +1070,23 @@ async def create_feedback(
             comment=feedback_from_langsmith.comment,
         )
 
-    async def check_feedback_enabled(self, config_hash: str = "") -> None:
-        """Check if feedback is enabled for the runnable."""
-        if not tracing_is_enabled() or not self._enable_feedback_endpoint:
+    async def _check_feedback_enabled(self, config_hash: str = "") -> None:
+        """Check if feedback is enabled for the runnable.
+
+        This endpoint is private since it will be deprecated in the future.
+
+        """
+        if not (await self.check_feedback_enabled(config_hash)):
             raise HTTPException(
                 400,
                 "The feedback endpoint is only accessible when LangSmith is "
                 + "enabled on your LangServe server.",
             )
 
+    async def check_feedback_enabled(self, config_hash: str = "") -> bool:
+        """Check if feedback is enabled for the runnable."""
+        return self._enable_feedback_endpoint or not tracing_is_enabled()
+
 
 _MODEL_REGISTRY = {}
 _SEEN_NAMES = set()

langserve/server.py

@@ -537,6 +537,12 @@ def _route_name_with_config(name: str) -> str:
 
         check_feedback_enabled = app.head(
             namespace + "/feedback",
+        )(api_handler._check_feedback_enabled)
+
+        # Add get version which returns True/False for flow control
+        # instead of 200/400 for flow control
+        app.get(
+            namespace + "/feedback",
         )(api_handler.check_feedback_enabled)
 
         if endpoint_configuration.is_config_hash_enabled:  # Is this needed?

tests/unit_tests/test_server_client.py

@@ -1905,6 +1905,7 @@ async def test_endpoint_configurations() -> None:
         ("GET", "/config_schema", {}),
         ("GET", "/playground/index.html", {}),
         ("HEAD", "/feedback", {}),
+        ("GET", "/feedback", {}),
         # Check config hashes
         ("POST", "/c/1234/invoke", {"input": 1}),
         ("POST", "/c/1234/batch", {"inputs": [1, 2]}),