Golangで再帰関数を書く - Qiita

func unpackStruct(data interface{}) interface{} { switch d := data.(type) { case *structpb.Struct: _metadata := make(map[string]interface{}) for k, x := range d.Fields { _metadata[k] = unpackStruct(x.GetKind()) } return _metadata case *structpb.Value_StructValue: _metadata := make(map[string]interface{}) for k, x := range d.StructValue.Fields { _metadata[k] = unpackStruct(x.GetKind()) } return _me