gistfile1.txt

(def ^:dynamic *counters*)

(defn new-counter [name]
  "Creates a pair of LongAdders"
  ...)

(defn get-counter [name]
  (if-let [ctr (get *counter* name]
    ctr
    (let [c (new-counter name)
      (set! *counters* (assoc *counters* c))
      c)))

(defn record-value [k v]
  (record-counter (get-counter k) v))

; ^^ Part of our existing metrics library

(defn on-event
  [k v]
  (when *counters*
    (record-value k v)))