progress_tracker.clj

(ns clj-gatling.progress-tracker
  (:require [clj-gatling.simulation-runners :as runners])
  (:import  (java.time LocalDateTime)
            (java.util.concurrent Executors TimeUnit)))

(defn create-console-progress-tracker []
  (let [finished? (atom false)
        width     (atom 0)]
    (fn [{:keys [progress sent-requests total-concurrency]}]
      (when-not @finished?
        (let [progress-percent (int (* 100 progress))
              report-str (str "Progress: " progress-percent "%, concurrency: " total-concurrency " , sent requests: " sent-requests)
              [previous-width new-width] (swap-vals! width (fn [_] (count report-str)))
              length-diff (- previous-width new-width)
              blanking (if (< 0 length-diff) (apply str (repeat length-diff " ")) "")]
          (print report-str blanking "\r")
          (when (= 100 progress-percent)
            (reset! finished? true)
            (println ""))
          ;;Flush is required for forcing writing to console in every round
          (flush))))))

(defn start [{:keys [progress-tracker
                     default-progress-tracker
                     runner
                     force-stop-fn
                     simulation-requests
                     start-time
                     scenario-concurrency-trackers]}]
  (let [executor (Executors/newSingleThreadScheduledExecutor)
        stop-fn (fn []
                  (.shutdownNow executor))
        runnable (fn []
                   (try
                     (let [sent-requests (:sent @simulation-requests)
                           [progress _]  (runners/calculate-progress runner sent-requests @start-time (LocalDateTime/now))
                           total-concurrency (reduce + (map deref (vals scenario-concurrency-trackers)))]
                       (progress-tracker {:progress progress
                                          :sent-requests sent-requests
                                          :total-concurrency total-concurrency
                                          :default-progress-tracker default-progress-tracker
                                          :force-stop-fn force-stop-fn}))
                     (catch Exception e
                       (println "Failed to run progress tracker" progress-tracker "with exception" e))))]
    (.scheduleAtFixedRate executor runnable 10 200 TimeUnit/MILLISECONDS)
    stop-fn))