[SOLVED] Fix "should not use basic type string as key in context.WithValue" golint

Fix "should not use basic type string as key in context.WithValue" golint

I am passing an uuid in using the Context and WithValue to subsequent functions that handle this *http.request. This uuid is was passed in the authorization header to a REST call to identify a person. The authorization token is verified and needs to accessible to check if the call is itself is authorized.

I used:

ctx := context.WithValue(r.Context(), string("principal_id"), *id)

But golint complains:

should not use basic type string as key in context.WithValue

What is the best option that could be used to retrieve this key that is not a basic type like a simple string?

Solution

Just use a key type:

type key int

const (
    keyPrincipalID key = iota
    // ...
)

Since you've defined a separate type, it will never collide. Even if you have two packages, pkg1.key(0) != pkg2.key(0).