Clojurians Log v2

I need help accessing my environment variables. I have :my-variable "value" in dev-config.edn and I'm trying to access it in another place. I required [my-app.config :refer [env]] and trying the following:

(defn my-function []
  (def variable (-> env :my-variable))
  (println (str "my environment variable: " variable)))

This doesn't work so what am I doing wrong? I also tried several other things...