用Python实现批量测试一组url的可用性（可以包括HTTP状态、响应时间等）并统计出现不可用情况的次数和频率等。

类似的，这样的脚本可以判断某个服务的可用性，以及在众多的服务提供者中选择最优的。

需求以及脚本实现的功能如下：

默认情况下，执行脚本会检测一组url的可用性。

如果可用，返回从脚本所在的机器到HTTP服务器所消耗的时间和内容等信息。

如果url不可用，则记录并提示用户，并显示不可用发生的时间。

默认情况下，允许最大的错误次数是200，数目可以自定义，如果达到允许的最大错误次数，则在输出信息的最后，根据每一个url做出错误统计。

如果用户手动停止脚本，则需要在输出信息的最后，根据每一个url做出错误统计。

脚本中涉及的一些技巧：

使用gevent并发处理多个HTTP请求，多个请求之间无须等待响应（gevent还有很多使用技巧，可再自行学习）；

使用signal模块捕获信号，如果捕获到则处理并退出，避免主进程接收到KeyboardInterrupt直接退出但无法处理的问题；

注意留意脚本中关于统计次数方面的小技巧；

脚本运行效果图（ 如果图片看不清楚，请选择“在新标签页中打开图片” ）如下：

脚本如下：

#!/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)