Start of rate limit video. there is a bug where the wrap-once-in-a-while function is not thread safe

rate-limit-start.clj

(ns scratch.core)

(defn say-hi [username]
  (let [s (str "hello, " username)]
    (Thread/sleep (rand 100))
    (println s)
    s))


(defn wrap-once-in-a-while [msecs-period f]
  (let [last-executed_ (atom 0)]
    (fn wrapper [& args]
      (let [now (System/currentTimeMillis)
            last-executed @last-executed_
            elapsed (- now last-executed)]
        
        (when (>= elapsed msecs-period)
          (let [result
                (try
                  (do                {:okay  (apply f args)})
                  (catch Throwable t {:error t}))]
            (reset! last-executed_ now)
            result))))))


(comment
  (let [wf (wrap-once-in-a-while 100 say-hi)]
    [(wf "on the code again")
     (wf "on the code again")
     (wf "on the code again")]))