How to create a CRUD with gRPC service without much repetition?

Question

I'm trying to use gRPC to build a simple CRUD service, but I keep finding myself creating messages with big overlaps.

This is best described by an example:

message Todo {
  // id is only available for a persisted entity in database.
  string id = 1;
  string content = 2;
  // this is only available for users with admin role.
  string secret_content = 3;
}

service Todos {
  rpc CreateTodo(CreateRequest) returns (CreateResponse) {}
  rpc ReadTodo(ReadRequest) returns (ReadResponse) {}
}

message CreateRequest {
  // this todo is not supposed to have id,
  // should I create another version of Todo without an id field?
  Todo todo
}

message CreateResponse {
  // this todo will always have an id.
  Todo todo = 1;
}

message ReadRequest {
  string id = 1;
}

message ReadResponse {
  // this todo should only have the secret_content field if the
  // user is authenticated as an admin, if not, the field should not
  // fallback to the zero value, the whole field must be missing. 
  Todo todo = 1;
}

Is this a good approach to build a CRUD like resource with gRPC? That is, having a single message (Todo) representing the resource, and wrapping this message in response/request types per action.

Should the Todo type message have all fields covered by all requests/responses, and not set the ones which are not in use by each?

Answer 1

Should the Todo type message have all fields covered by all requests/responses, and not set the ones which are not in use by each?

Yes, this seems like a reasonable design. In protobuf v2, you would have marked such fields optional to make it easier to understand. But in v3, all fields are optional by default anyway.