Example Protocol Buffer schema definition

car.proto

syntax = "proto3";

option java_multiple_files = true;
option java_package = "schema";
option java_generic_services = true;

// An RPC service which has a method to request a list of cars.
service CarService {
  rpc GetCars(GetCarsRequest) returns (GetCarsResponse);
}

// The shape of a valid request to our service.
message GetCarsRequest {
  Manufacturer manufacturer = 1;
}

// The shape of a valid response from our service.
message GetCarsResponse {
  repeated Car cars = 1;
}

enum Manufacturer {
  UNKOWN_MANUFACTURER = 0;
  TOYOTA = 1;
  HONDA = 2;
}

message Car {
  Manufacturer manufacturer = 1;
  string model = 2;
}