在Go中使用“ oneof”构建protobuf消息

Question

I've recently started toying with GoLang and Protocol Buffers, I have the following messages I'm trying to use

message KumoAPIMessage {
  oneof msg {
    OpenStackEnvironmentContext osEnvContext = 1;
  }
}

message OpenStackEnvironmentContext {
  string username = 1;
  string password = 2;
  string domain = 3;
  string project = 4;
  string authUrl = 6;
  string region = 7;
  string contextName = 8;
}

These messages are deisgned so that they can be marshaled and sent via TCP to a server agent (written in Scala). The problem I'm having is actually building the messages in the go application.

I have got a OpenStackEnvironmentContext message made but I can't work out how to wrap it in the KumoAPIMessage, I've tried the following

apiMessage := kumo.KumoAPIMessage{ Msg: context, }

But that just sends up throwing the following error on compile

cannot use context (type kumo.OpenStackEnvironmentContext) as type kumo.isKumoAPIMessage_Msg in field value:
kumo.OpenStackEnvironmentContext does not implement kumo.isKumoAPIMessage_Msg (missing kumo.isKumoAPIMessage_Msg method)

If any one has any clue about where I am going wrong, you will be my hero.

Answer 1

For once I have been able to answer my own question. With a lot of googling and experimenting I have gotten to the following solution

apiMessage := &kumo.KumoAPIMessage{&kumo.KumoAPIMessage_OsEnvContext{context}}

It seems that the GoLang compiler for protobufs generates a struct for the wrapper message AND a struct for the message type it is wrapping