Dynamic typing - Timeout

Another piece of useful functionality made easy by dynamic typing and clojure.async. Adding a timeout to a function.

	(ns clojure-study.ideas.timeouter
	(:require [clojure.core.async :as async]))
	(defn add-timeout
	"f - the original function
	timeout-ms - timeout in milliseconds
	timeout-value - the value the function should return in case of timeout"
	[f timeout-ms timeout-value]
	(fn [& args]
	(let [timeout-channel (async/timeout timeout-ms)
	result-channel (async/thread (apply f args))
	[r c] (async/alts!! [timeout-channel result-channel])]
	(if (= c timeout-channel)
	timeout-value ;; if timeout
	r)))) ;; if successful
	;; ----- THAT'S IT. LET'S SEE A DEMONSTRATION ------------
	;a slow function
	(defn slow-fn []
	(Thread/sleep 100)
	:slow)
	;a fast function
	(defn fast-fn []
	(Thread/sleep 10)
	:fast)
	;add 50 ms timeouts to both, returning the :timeout fall-back value
	(def slow-with-timeout (add-timeout slow-fn 50 :timeout))
	(def fast-with-timeout (add-timeout fast-fn 50 :timeout))
	;see the results
	(println "Here comes the slow:" (slow-with-timeout))
	;Here comes the slow: :timeout
	(println "Here comes the fast:" (fast-with-timeout))
	;Here comes the fast: :fast

view raw timeouter.clj hosted with ❤ by GitHub