Create variable of type Map[string]interface{} in gRPC protoc buffer golang

Radhika.S picture Radhika.S · Oct 26, 2016 · Viewed 16.2k times · Source

I'm using grpc golang to communicate between client and server application. Below is the code for protoc buffer.

syntax = "proto3";
package Trail;

service TrailFunc {
  rpc HelloWorld (Request) returns (Reply) {}
}

// The request message containing the user's name.
message Request {
  map<string,string> inputVar = 1;
}
// The response message containing the greetings
message Reply {
  string outputVar = 1;
}

I need to create a field inputVar of type map[string]interface{} inside message data structure instead of map[string]string. How can I achieve it? Thanks in advance.

Answer

Marcel Novy picture Marcel Novy · Oct 26, 2016

proto3 has type Any

import "google/protobuf/any.proto";

message ErrorStatus {
  string message = 1;
  repeated google.protobuf.Any details = 2;
}

but if you look at its implementation, it is simply as

message Any {
  string type_url = 1;
  bytes value = 2;
}

You have to define such a message yourself by possibly using reflection and an intermediate type.

See example application

https://github.com/golang/protobuf/issues/60