golang protobuf remove omitempty tag from generated json tags

Question

I am using google grpc with a json proxy. for some reason i need to remove the omitempty tags from the struct generated in the *.pb.go files.

if i have a proto message like this

message Status {   int32 code = 1;   string message = 2; } 

The generated struct looks like this

type Status struct {   Code int32 `protobuf:"varint,1,opt,name=code" json:"code,omitempty"`   Message string `protobuf:"bytes,2,opt,name=message" json:"message,omitempty"` } 

But My need is to remove the omitempty tag from the generated structs. How can i do this?

Answer 1

If you are using grpc-gateway and you need the default values to be present during json marshaling, you may consider to add the following option when creating your servemux

    gwmux := runtime.NewServeMux(runtime.WithMarshalerOption(runtime.MIMEWildcard, &runtime.JSONPb{OrigName: true, EmitDefaults: true})) 

Outside of grpc-gateway, if you want to marshal your protocul buffer message, use github.com/golang/protobuf/jsonpb package instead of encoding/json

func sendProtoMessage(resp proto.Message, w http.ResponseWriter) {     w.Header().Set("Content-Type", "application/json; charset=utf-8")     m := jsonpb.Marshaler{EmitDefaults: true}     m.Marshal(w, resp) // You should check for errors here } 

Answer 2

A [more] portable solution:

Use sed to strip the tags after generating via protoc.

Example of what I actually use in my go:generate script after having generated the *.pb.go files:

ls *.pb.go | xargs -n1 -IX bash -c 'sed s/,omitempty// X > X.tmp && mv X{.tmp,}' 

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Note: sed -i (inline-replacement) is not used here because that flag isn't portable between standard OS-X and Linux.