gRPC异步服务pytest测试报错StatusCode.UNKNOWN问题求助

问题背景 #

我实现了一个小型gRPC异步服务，使用pytest编写异步测试用例进行验证，测试代码如下：

@pytest.mark.asyncio
async def test_poc_server():
    # 启动poc服务
    server = PoCGrpcServer(50051)
    await server.start()
    # 创建连接到服务的客户端
    async with grpc.aio.insecure_channel('localhost:50051') as channel:
        stub = PoCStub(channel)
        response = await stub.Move(poc__pb2.MoveRequest(x=10.0, y=10.0))
    assert response.result() == poc__pb2.MoveResponse

报错信息 #

测试在执行stub.Move()时失败，报错如下：

>           response = await stub.Move(poc__pb2.MoveRequest(x=10.0, y=10.0))

tests/test_grpc_server.py:51: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <_AioCall of RPC that terminated with:
        status = Exception calling application: 
        details = "StatusCode.UNKNOWN"
        debu...peer  {created_time:"2023-06-15T14:38:59.0601+02:00", grpc_status:2, grpc_message:"Exception calling application: "}"
>

    def __await__(self) -> ResponseType:
        """Wait till the ongoing RPC request finishes."""
        try:
            response = yield from self._call_response
        except asyncio.CancelledError:
            # Even if we caught all other CancelledError, there is still
            # this corner case. If the application cancels immediately after
            # the Call object is created, we will observe this
            # `CancelledError`.
            if not self.cancelled():
                self.cancel()
            raise
    
        # NOTE(lidiz) If we raise RpcError in the task, and users doesn't
        # 'await' on it. AsyncIO will log 'Task exception was never retrieved'.
        # Instead, if we move the exception raising here, the spam stops.
        # Unfortunately, there can only be one 'yield from' in '__await__'. So,
        # we need to access the private instance variable.
        if response is cygrpc.EOF:
            if self._cython_call.is_locally_cancelled():
                raise asyncio.CancelledError()
            else:
>               raise _create_rpc_error(self._cython_call._initial_metadata,
                                        self._cython_call._status)
E               grpc.aio._call.AioRpcError: <AioRpcError of RPC that terminated with:
E                       status = StatusCode.UNKNOWN
E                       details = "Exception calling application: "
E                       debug_error_string = "UNKNOWN:Error received from peer  {created_time:"2023-06-15T14:38:59.0601+02:00", grpc_status:2, grpc_message:"Exception calling application: "}"
E               >

../../../../Library/Caches/pypoetry/virtualenvs/pytaf-6R8xcXyw-py3.11/lib/python3.11/site-packages/grpc/aio/_call.py:290: AioRpcError

现有猜测与求助 #

• 猜测问题可能和服务与客户端运行在同一个asyncio运行器有关，但不确定。
• 注意到pytest-grpc库也存在类似错误，但不清楚具体修复方案。
• 寻求该问题的排查思路与解决方法。

内容的提问来源于stack exchange，提问作者sebastianpfischer