用Python實現(xiàn)批量測試一組url的可用性（可以包括HTTP狀態(tài)、響應(yīng)時間等）并統(tǒng)計出現(xiàn)不可用情況的次數(shù)和頻率等。

類似的，這樣的腳本可以判斷某個服務(wù)的可用性，以及在眾多的服務(wù)提供者中選擇最優(yōu)的。

需求以及腳本實現(xiàn)的功能如下：

默認情況下，執(zhí)行腳本會檢測一組url的可用性。 如果可用，返回從腳本所在的機器到HTTP服務(wù)器所消耗的時間和內(nèi)容等信息。 如果url不可用，則記錄并提示用戶，并顯示不可用發(fā)生的時間。 默認情況下，允許最大的錯誤次數(shù)是200，數(shù)目可以自定義，如果達到允許的最大錯誤次數(shù)，則在輸出信息的最后，根據(jù)每一個url做出錯誤統(tǒng)計。 如果用戶手動停止腳本，則需要在輸出信息的最后，根據(jù)每一個url做出錯誤統(tǒng)計。

腳本中涉及的一些技巧：

使用gevent并發(fā)處理多個HTTP請求，多個請求之間無須等待響應(yīng)（gevent還有很多使用技巧，可再自行學習）； 使用signal模塊捕獲信號，如果捕獲到則處理并退出，避免主進程接收到KeyboardInterrupt直接退出但無法處理的問題； 注意留意腳本中關(guān)于統(tǒng)計次數(shù)方面的小技巧；

腳本運行效果圖（ 如果圖片看不清楚，請選擇“在新標簽頁中打開圖片” ）如下：

腳本如下：

#!/usr/bin/python# encoding: utf-8# -*- coding: utf8 -*-"""Created by PyCharm.File:    LinuxBashShellScriptForOps:testNoHttpResponseException,testHttpHostAvailability.pyUser:    GuodongCreate Date:  2016/10/26Create Time:  12:09Function: test Http Host AvailabilitySome helpful message: For CentOS: yum -y install python-devel python-pip; pip install gevent For Ubuntu: apt-get -y install python-dev python-pip; pip install gevent For Windows: pip install gevent """import signalimport timeimport sys# execute some operations concurrently using pythonfrom gevent import monkeymonkey.patch_all()import geventimport urllib2hosts = ['https://webpush.wx2.qq.com/cgi-bin/mmwebwx-bin/synccheck',   'https://webpush.wx.qq.com/cgi-bin/mmwebwx-bin/synccheck', ]errorStopCounts = 200quit_flag = Falsestatistics = dict()def changeQuit_flag(signum, frame): del signum, frame global quit_flag quit_flag = True print "Canceled task on their own by the user."def testNoHttpResponseException(url): tryFlag = True global quit_flag errorCounts = 0 tryCounts = 0 global statistics globalStartTime = time.time() while tryFlag:  if not quit_flag:   tryCounts += 1   print('GET: %s' % url)   try:    startTime = time.time()    resp = urllib2.urlopen(url) # using module 'request' will be better, request will return header info..    endTime = time.time()    data = resp.read()    responseTime = endTime - startTime    print '%d bytes received from %s. response time is: %s' % (len(data), url, responseTime)    print "data received from %s at %d try is: %s" % (url, tryCounts, data)    gevent.sleep(2)   except urllib2.HTTPError as e:    errorCounts += 1    statistics[url] = errorCounts    currentTime = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime())    print "HTTPError occurred, %s, and this is %d times(total) occurs on %s at %s." % (     e, statistics[url], url, currentTime)    if errorCounts >= errorStopCounts:     globalEndTime = time.time()     tryFlag = False  else:   globalEndTime = time.time()   break for url in statistics:  print "Total error counts is %d on %s" % (statistics[url], url)  hosts.remove(url) for url in hosts:  print "Total error counts is 0 on %s" % url globalUsedTime = globalEndTime - globalStartTime print "Total time use is %s" % globalUsedTime sys.exit(0)try: # Even if the user cancelled the task, # it also can statistics the number of errors and the consumption of time for each host. signal.signal(signal.SIGINT, changeQuit_flag) gevent.joinall([gevent.spawn(testNoHttpResponseException, host) for host in hosts])except KeyboardInterrupt: # Note: this line can NOT be reached, because signal has been captured! print "Canceled task on their own by the user." sys.exit(0)