How to get gRPC to properly serialize response - grpc

Question

getting a strange error when trying simple gRPC implementation I.e. following the standard python example. Server seems to run OK, but get the error when I ping it with a client
grpc:
package pas;
// The PAS service definition
service PAS {
// analyze single file
rpc getPhotonRecords (PhotonRecordsRequest) returns (PhotonRecordsReply) {}
}
message PhotonRecordsRequest {
string fileName = 1;
}
message PhotonRecordsReply {
repeated uint32 PhotonRecords = 1;
}
client:
with grpc.insecure_channel("localhost:50051") as channel:
stub = pas_pb2_grpc.PASStub(channel)
msg = pas_pb2.PhotonRecordsRequest(fileName='testingFilename.flb')
response = stub.getPhotonRecords(msg)
server:
class PAS_GRPC(pas_pb2_grpc.PASServicer):
def getPhotonRecords(self, request: pas_pb2.PhotonRecordsRequest, context):
# check for required fields and error if not there or valid
# update any optional fields that the request has specified
PhotonRecordsReply = pas_pb2.PhotonRecordsReply()
PhotonRecordsReply.PhotonRecords.extend([1, 3, 7])
return pas_pb2.PhotonRecordsReply
client error:
<_InactiveRpcError of RPC that terminated with:
status = StatusCode.INTERNAL
details = "Failed to serialize response!"
server error:
TypeError: IsInitialized() missing 1 required positional argument: 'self'

Answer 1

Your server method getPhotonRecords returns the type:
return pas_pb2.PhotonRecordsReply
But it should return the variable you created:
return PhotonRecordsReply
You may want to use snake_case for variables to help differentiate from CamelCase class names, i.e.:
photon_records_reply = pas_pb2.PhotonRecordsReply()
...