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goprotocol-buffersgrpc

Protocol buffer zero value for integer

I have a Go struct what we are using currently in our restful API which looks like this:

type Req struct {
  Amount *int
}

I'm using pointer here, because if the Amount is nil, it means the Amount was not filled, if the Amount isn't nil, but it's zero, it means the field was filled, but the value is zero.

When we started to change to protofiles and we want to use it like, the main API get's the request as HTTP API and send it to the next service through gRPC with the same protofile I faced with the issue, the proto3 can't generate pointer for the Amount. That's fine because the protocol buffers designed for the purpose of sending data between separated systems, but how can I handle the issue above, because if I get the request I can't decide that the Amount is nil or just zero.

Solution

  • Update July 2023

    The current Accepted answer is no longer true. proto3 now supports the optional parameter which will generate a field with a pointer satisfying the original question. See https://protobuf.dev/reference/go/go-generated/#singular-scalar-proto3

    For example:

    message Foo {
   optional int32 bar = 1;
}

    generates

    type Foo struct {
   bar *int32
}