异步DNS解析程序测试

Question

我想测试大量的IP来寻找开放的DNS解析程序。我正试图找到最有效的方法来并行处理。目前我正试图用twisted来完成这个任务。我希望有10或20个并行线程发送一个查询，以避免阻塞槽超时。在

Twisted有一个DNSDatagramProtocol，看起来很合适，但我就是不知道如何将它与Twisted“reactor”和“threads”设施结合起来，使其高效运行。在

我读了很多twisted文档，但我仍然不确定什么是最好的方法。在

有人能举个例子吗？在

Answer 1

试试gevent，生成许多greenlet来做一个DNS解析。gevent还有一个不错的DNS解析API:http://www.gevent.org/gevent.dns.html

他们甚至有一个例子： https://github.com/gevent/gevent/blob/master/examples/dns_mass_resolve.py

Answer 2

下面是一个演示Twisted Names API的快速示例：

from sys import argv
from itertools import cycle
from pprint import pprint

from twisted.names import client
from twisted.internet.task import react
from twisted.internet.defer import gatherResults, inlineCallbacks

def query(reactor, server, name):
    # Create a new resolver that uses the given DNS server
    resolver = client.Resolver(
        resolv="/dev/null", servers=[(server, 53)], reactor=reactor)
    # Use it to do an A request for the name
    return resolver.lookupAddress(name)

@inlineCallbacks
def main(reactor, *names):
    # Here's some random DNS servers to which to issue requests.
    servers = ["4.2.2.1", "8.8.8.8"]

    # Handy trick to cycle through those servers forever
    next_server = cycle(servers).next

    # Issue queries for all the names given, alternating between servers.
    results = []
    for n in names:
        results.append(query(reactor, next_server(), n))
    # Wait for all the results
    results = yield gatherResults(results)
    # And report them
    pprint(zip(names, results))

if __name__ == '__main__':
    # Run the main program with the reactor going and pass names
    # from the command line arguments to be resolved
    react(main, argv[1:])