Is Golang (Go) language supported in DSS
DSS is a REST API, and any programming language which supports REST interface can be used with it. In terms of support, only C# SDK is supported by the DSS product. Other languages will have to use the REST interface to get data.
Go has some community support for REST interface. See this example.
You can refer to this article on developers forum which demonstrates GO programming with a working RTH sample. The sample code can be re-used with DSS after trivial modifications.