Publish RPC

With dial-out telemetry, where the SR OS node is the gRPC client instead of the gRPC server, the SR OS node sends a Publish RPC with a ‟SubscribeResponse” message to the gRPC server. (See Dial-out telemetry.)

Because the current gnmi.proto definition does not support dial-out mode, a protobuf definition is introduced, with a separate gRPC service, as follows:

NOKIA-DialOut.proto
      option (dialout_service) = 0.1.0
      service gMIDialOut {
              rpc Publish(stream SubscribeResponse) returns (stream PublishResponse)
      }
      message PublishResponse {
      }

The preceding proto file definition reuses the ‟SubscribeResponse” message defined for dial-in telemetry, in accordance with the gNMI specification.