We’re seeing hundreds of these errors per day in LangGraph Cloud, firing on graph invocations -
[ERROR] Exception in callback functools.partial(<bound method PollerCompletionQueue._handle_events of <grpc._cython.cygrpc.PollerCompletionQueue object at 0x7ff3947ac660>>, <uvloop.Loop
running=True closed=False debug=False>)
Traceback (most recent call last):
File “uvloop/cbhandles.pyx”, line 61, in uvloop.loop.Handle._run
File “src/python/grpcio/grpc/_cython/_cygrpc/aio/completion_queue.pyx.pxi”, line 154, in grpc._cython.cygrpc.PollerCompletionQueue._handle_events
BlockingIOError: [Errno 11] Resource temporarily unavailable
The gRPC dependency comes from langgraph-api itself (grpcio >= 1.75.0, grpcio-health-checking, grpcio-tools), not our application code. This appears to be a grpcio + uvloop incompatibility where
the PollerCompletionQueue pipe fd triggers EAGAIN under uvloop.
Graphs execute correctly — the errors seem cosmetic — but they pollute logs at ERROR level and trigger alert fatigue in monitoring tools.
Environment: langgraph 1.0.7, langgraph-sdk 0.3.3, grpcio 1.76.0, Python 3.12, deployed to LangGraph Cloud.
Is this a known platform issue? Any planned fix or recommended workaround?
Any guidance appreciated — happy to provide more logs or details.