rabbitmq / langohr detecting changed topology attempt

try-topology.clj

(defn try-topology [conn fn]
  (let [ch (lch/open conn)]
    (try
      (fn conn ch)
      true
      (catch IOException e
        (when-not (instance? ShutdownSignalException (.getCause e))
          (throw (Exception. "Unexpected exception trying RabbitMQ operation" e)))
        (let [reason (-> e .getCause .getReason)]
          (when-not (instance? AMQP$Channel$Close reason)
            (throw (Exception. (str "Unexpected reason trying RabbitMQ operation:" reason) e)))
          (when-not (= 406 (.getReplyCode reason))
            (throw (Exception. (str "Unexpected reply code:" (.getReplyCode reason) " - " (.getReplyText reason)) e)))
          false)))))