mkdir if not exists using golang

Okay I figured it out thanks to this question/answer

import(
    "os"
    "path/filepath"
)

newpath := filepath.Join(".", "public")
err := os.MkdirAll(newpath, os.ModePerm)
// TODO: handle error

Relevant Go doc for MkdirAll:

MkdirAll creates a directory named path,
along with any necessary parents, and returns nil,
or else returns an error.

…

If path is already a directory, MkdirAll does nothing
and returns nil.