Multiple References to a Connection Pool (perhaps incorrect?)

gist.clj

(def datasources (agent {}))

(defn make-datasource [db-conf]
  (send-off datasources
            (fn [datasources]
              (if-let [ds-conf (get datasources db-conf)]
                (update-in datasources [db-conf :count] inc)
                (assoc datasources
                       db-conf {:count 1
                                :ds (conn-pool/make-datasource db-conf)}))))
  (await datasources)
  (:ds (get @datasources db-conf)))

(defn close-datasource [db-conf]
  (send-off
   datasources
   (fn [datasources]
     (if-let [{:keys [count ds]} (get datasources db-conf)]
       (if (= count 1)
         (do
           (conn-pool/close-datasource ds)
           (dissoc datasources db-conf))         
         (update-in datasources [db-conf :count] dec))
       (throw (Exception. "Cannot close nonexistent datasource"))))))
     
;; ... elsewhere:
(let [conn-pool-ds (make-datasource db-conf)]
    (jdbc/query {:datasource conn-pool-ds} ["select * from foo"]))