Tests speed of http mirrors of cygwin

cygwin-mirror-speed.py

#!/usr/bin/env python3
"""
Tests http mirrors of cygwin
"""
import random
import time
from urllib.request import  urlopen
import sys
from multiprocessing import Pool, TimeoutError

__author__ = 'Dmitry Sidorenko'
 
mirrors_url = "http://cygwin.com/mirrors.lst"
test_file = "/x86_64/setup.ini"
block_sz = 8096
 
def test_host(hostentry):
  host = hostentry["host"]
  sys.stdout.flush()
  start_time = time.time()
  try:
    test = urlopen(host[0] + test_file, timeout=5)
    test.read(block_sz)
    time_spent = time.time() - start_time
    hostentry["time"] = time_spent
    print("testing mirror %s ... %s sec" % (host[1], time_spent))
  except IOError:
    hostentry["time"] = 9999
    print("testing mirror %s ... timeout" % host[1])
  return hostentry
 
if __name__ == '__main__':
 
  mirrors = [
    #    {"host": "",
    #     "time": 1
    #  }
  ]
  print("Downloading mirrors list...", end='')
  sys.stdout.flush()
  u = urlopen(mirrors_url)
  for line in u:
    strline = str(line)[2:-3]
    host = strline.split(";")
    # Only test http
    if host[0].startswith("http://"):
      mirrors.append({"host": host, "time": 9999})
  print("done, %d entries" % len(mirrors))
  random.shuffle(mirrors)
 
  max_hosts_to_try = 100
  testn = 1
 
  num_processors = len(mirrors) / 2.0
  with Pool(processes=int(num_processors)) as pool:
    result = pool.map(test_host, mirrors)
    mirrors = result
 
  mirrors = sorted(mirrors, key=lambda entry: entry["time"])
 
  print("\nTop 5 mirrors\n")
  sys.stdout.flush()
 
  for i in range(5):
    mirror = mirrors[i]
    host_info = mirror["host"]
    if mirror["time"] < 9999:
      print("%.3f, %14s, %10s, %s" % (mirror["time"], host_info[2], host_info[3], host_info[0]), file=sys.stderr)

Modification on the original script to run the tests in parallel using multiprocessing.Pool.map(). This cuts down the time required to find the fastest servers.