Similar to .net attributes in Go

Question

What is similar to .net attributes in go lang.

Or how this could be achieved ?

Answer 1

Perhaps the most similar mechanism is Struct Tags. Not the most elegant, but they can be evaluated at runtime and provide metadata on struct members.

From the reflect package documentation: type StructTag

They are used, for example, in JSON and XML encoding for custom element names.

For example, using the standard json package, say I have a struct with a field I don't want to appear in my JSON, another field I want to appear only if it is not empty, and a third one I want to refer to with a different name than the struct's internal name. Here's how you specify it with tags:

type Foo struct {
    Bar string `json:"-"` //will not appear in the JSON serialization at all
    Baz string `json:",omitempty"` //will only appear in the json if not empty
    Gaz string `json:"fuzz"` //will appear with the name fuzz, not Gaz
}

I'm using it to document and validate parameters in REST API calls, among other uses.

If you keep the 'optionally space-separated key:"value"' syntax, you can use the Get Method of StructTag to access the values of individual keys, as in the example.