架构师训练营第七周 - 作业

(ns load-tester.core
  (:gen-class)
  (:refer-clojure :exclude [time])
  (:require [clojure.core.async :refer (thread <!!)]
            [org.httpkit.client :as http]
            )
  )
(defmacro time
  "对表达式求值并计算执行时间，返回执行时间（毫秒为单位）及表达式的值"
  [expr]
  `(let [start# (. System (nanoTime))
         ret# ~expr]
     {:time (/ (double (- (. System (nanoTime)) start#)) 1000000.0)
      :ret ret#
      }
     )
  )
(defn access-url "访问 url" [url]
  (let [{:keys [status headers body error] :as resp} @(http/get url)]
    (not error)
    )
  )
(defn time-access-url "访问 url，记录响应时间" [url]
  (time (access-url url))
  )
(defn test-url "访问 url 若干次，记录每次的响应时间" [url times]
  (doall (repeatedly times #(time-access-url url)))
  )
(defn percentile "计算百分位" [coll p]
  (nth (sort coll) (int (/ (* (count coll) p) 100)))
  )
(defn -main [arg1 arg2 arg3 & args]
  (let [;; 并线程数
        concurrency (Integer/valueOf arg1)
        ;; 每个线程请求数
        times (Integer/valueOf arg2)
        ;; 百分位
        p (Integer/valueOf arg3)
        url "https://www.baidu.com"
        results (->> (repeatedly concurrency #(<!! (thread (test-url url times))))
                     flatten
                     (map :time)
                     )
        sorted-results (sort results)
        average-time (/ (apply + results) (* concurrency times))
        ]
    (println (format "average: %sms min: %sms max: %sms" average-time (first sorted-results) (last sorted-results)))
    (println (format "%dth percentile: %sms" p (percentile results p)))
    )
  )

➜ lein run 10 100
average: 11.067140267000005ms min: 8.943479ms max: 187.379443ms
95th percentile: 12.231237ms