a generic clojure web app

app.clj

(defn app
  "create a new application. returns function to stop the application"
  [configurations]
  (let [state1 (ref {})
        state2 (ref {})
        background-worker (schedule #(log-app-states
                                      (let [data1 (rest-query (:source1 configurations))
                                            data2 (rest-query (:source2 configurations))]
                                        (dosync (let [[s1 s2] (generate-new-states-which-is-pure data1 data2 @state1 @state2)]
                                                  (ref-set state1 s1)
                                                  (ref-set state2 s2)
                                                  [data1 data2 s1 s2])))))
        ring-app (routes
                   (GET "/update-state1/:value" [value]
                        (dosync (ref-set state1 (app-specific-logic1-which-is-pure @state1 value))))
                   (GET "/update-state2/:value" [value]
                        (dosync (ref-set state2 (app-specific-logic2-which-is-pure @state2 value))))
                   (route/not-found "PAGE_NOT_FOUND"))
        server (jetty/run-jetty ring-app {:port (int (:port configurations)) :join? false})]
    ;; start the background workder now
    (.start background-worker)
    ; return a function to *stop* the application for simple debugging
    #(do (.stop server)
         (.stop background-worker))))