与Python并行解析和保存主机名

Question

我正在尝试解析主机名列表.问题是当我遇到一个不存在的域时,它会减慢整个过程.代码是一个简单的for循环:

for domain in domains:
    try:
        if socket.gethostbyname(domain.split('@')[1]):
            file1.write(domain)
        else:
            file2.write(domain)
    except socket.gaierror:
        pass

我想知道是否有一种简单的方法来并行化for循环内部的内容.

Answer 1

您可以使用Gevent中的一个示例 - dns_mass_resolve.py.为所有查询设置超时也是有用的.

from __future__ import with_statement
import sys
import gevent
from gevent import socket
from gevent.pool import Pool

N = 1000
# limit ourselves to max 10 simultaneous outstanding requests
pool = Pool(10)
finished = 0


def job(url):
    global finished
    try:
        try:
            ip = socket.gethostbyname(url)
            print ('%s = %s' % (url, ip))
        except socket.gaierror:
            ex = sys.exc_info()[1]
            print ('%s failed with %s' % (url, ex))
    finally:
        finished += 1

with gevent.Timeout(2, False):
    for x in xrange(10, 10 + N):
        pool.spawn(job, '%s.com' % x)
    pool.join()

print ('finished within 2 seconds: %s/%s' % (finished, N))