wrap-db-connection.clj

(defn wrap-db-connection [handler config]
  (let [ds (doto (BasicDataSource.)
             (.setDriverClassName (:driver-classname config))
             (.setUrl (:url config))
             (.setUsername (:username config))
             (.setPassword (:password config)))]
    (fn [request]
      (sql/with-connection {:datasource ds}
        (handler request)))))

;; in some main file
(defn -main [& args]
  (let [config (read-config (first args))]
    (run-jetty
      (-> web/handler
          wrap-params
          (wrap-db-connection config))
      {:port (:port config)})))