background.clj

(ns background
  (:require [clojure.tools.logging :as log])
  (:import [java.util.concurrent]))

(defonce !executor (delay (java.util.concurrent.Executors/newCachedThreadPool)))

(defn background
  "Calls the fn passed in a thread from a thread pool, returning immediately.
  Unlike future, background does not swallow exceptions."
  [f]
  (.execute @!executor (fn [] (try
                                (f)
                                (catch Exception e
                                  (log/error "Uncaught exception in background thread:" e))))))