TypeError during the call python grpc method without arguments using google/protobuf/empty.proto

Question

I have a proto scheme like this:

   import "google/protobuf/empty.proto";
   ...

   service NodeInfoService {
   rpc NodeConfig (google.protobuf.Empty) returns (NodeConfigResponse);
}

Using grpc_tools I got classes and now, when I'm trying to send request from py client, but catching the error in "stub.NodeConfig()" call. Even If I call it like "stub.NodeConfig({})" or "stub.NodeConfig("")" I have the same TypeError. Full code of client:

import grpc
import logging
from util import node_info_service_pb2_grpc
from util import node_info_service_pb2

def run():
    with grpc.insecure_channel('ip:port') as channel:
        stub = node_info_service_pb2_grpc.NodeInfoServiceStub(channel)
        response = stub.NodeConfig(node_info_service_pb2.google_dot_protobuf_dot_empty__pb2.Empty)
    print("Echo client received: " + response.message)


if __name__ == '__main__':
    logging.basicConfig()
    run()

Error:

ERROR:grpc._common:Exception serializing message!
Traceback (most recent call last):
  File "/Users/user/p/p/venv/lib/python3.8/site-packages/grpc/_common.py", line 86, in _transform
    return transformer(message)
TypeError: descriptor 'SerializeToString' for 'google.protobuf.pyext._message.CMessage' objects doesn't apply to a 'GeneratedProtocolMessageType' object
Traceback (most recent call last):
  File "/Users/user/p/scripts/grpc/protobuf/client.py", line 15, in <module>
    run()
  File "/Users/user/p/scripts/grpc/protobuf/client.py", line 9, in run
    response = stub.NodeConfig(node_info_service_pb2.google_dot_protobuf_dot_empty__pb2.Empty)
  File "/Users/user/p/p/venv/lib/python3.8/site-packages/grpc/_channel.py", line 921, in __call__
    state, call, = self._blocking(request, timeout, metadata, credentials,
  File "/Users/user/p/p/venv/lib/python3.8/site-packages/grpc/_channel.py", line 901, in _blocking
    raise rendezvous  # pylint: disable-msg=raising-bad-type
grpc._channel._InactiveRpcError: <_InactiveRpcError of RPC that terminated with:
    status = StatusCode.INTERNAL
    details = "Exception serializing request!"
    debug_error_string = "None"

score 9 · Answer 1 · answered Dec 03 '20 at 15:43

9

Solution:

  empty = node_info_service_pb2.google_dot_protobuf_dot_empty__pb2.Empty()
  response = stub.NodeConfig(empty)

answered Dec 03 '20 at 15:43

liliya

251
3
6

There's a proper path for [Empty](https://googleapis.dev/python/protobuf/latest/google/protobuf/empty_pb2.html): import google.protobuf.empty_pb2; empty = google.protobuf.empty_pb2.Empty() – bain May 15 '23 at 10:48

TypeError during the call python grpc method without arguments using google/protobuf/empty.proto

1 Answers1