grpc_employee.proto

syntax = "proto2";
// there's also "proto3"

package employeebook;

option java_package = "com.cnb.employeebook";
option java_outer_classname = "EmployeeBookProtos";

service EmployeeService {
  // Get all employees
  rpc GetEmployees(Key) returns (stream Employee) {}
}

message Key {
  required string key = 1;
}

message Employee {
  ...