Atomic clojure.cache example

atomic-cache-example.clj

(require '[[clojure.cache :as cache]
           [clojure.string :as string]
           [cb-statsd :as statsd]])

(def STATSD_SAMPLE_RATE 0.01)

(defn get-statsd-path
  [f]
  (as-> (str (type f)) fname ;; returns something like "class namespace$foo"
    (last (string/split fname #" ")) ;; parse out the "class "
    (string/replace fname "$" "."))) ;; use a dot to seperate namespace

(defn update-cache
  [cache f & args]
  (if (cache/has? cache args)
    (do
      (statsd/increment (str (get-statsd-path) ".cache-hit") 1 STATSD_SAMPLE_RATE)
      (cache/hit cache args))
    (do
      (statsd/increment (str (get-statsd-path) ".cache-miss") 1 STATSD_SAMPLE_RATE)
      (cache/miss cache args (f args)))))

(def my-cache (atom (cach/ttl-cache-factory {} :ttl 1000000)))

(defn my-fn
  [a b c]
  (+ a b c))

(defn -main
  ...
  (swap! my-cache update-cache my-fn 1 2 3)
  (cache/lookup @my-cache [1 2 3]))