gistfile1.clj

;; SQS에 쌓인 메세지의 갯수를 보고 worker를 scale함

(def heroku-api-key (get (System/getenv) "HEROKU_API_KEY"))
(def heroku-app-id (get (System/getenv) "HEROKU_APP_ID"))
(def heroku-worker-name (get (System/getenv) "HEROKU_WORKER_NAME"))

(defn heroku-scale [api-key app-id type qty]
  (client/post (format "https://api.heroku.com/apps/%s/ps/scale" app-id)
               {:basic-auth ["" api-key]
                :accept :json
                :form-params {:type type
                              :qty qty}}))

(defn get-num-attr [attrs name]
  (Integer/parseInt
   (get attrs name "0")))

(defn -main []
  (if-not (or (empty? heroku-api-key)
              (empty? heroku-app-id)
              (empty? heroku-worker-name))
   (if-let [attrs (sqs/queue-attrs client dabang-queue)]
     (let [visible (get-num-attr attrs
                                 "ApproximateNumberOfMessages")
           not-visible (get-num-attr attrs
                                     "ApproximateNumberOfMessagesNotVisible")
           delayed (get-num-attr attrs
                                 "ApproximateNumberOfMessagesDelayed")
           all-count (+ visible not-visible delayed)]
       
       ;; Worker를 켜거나 끔
       (if (> all-count 0)
         (do
           (println "Scale up to " 1)
           (heroku-scale heroku-api-key heroku-app-id heroku-worker-name 1))
         (do
           (println "Scale down to 0")
           (heroku-scale heroku-api-key heroku-app-id heroku-worker-name 0))
         )))
   (println "Need api-key, app-id, and worker-name")))