A simple multi cpu twisted dns server on a single ip/port.

smp_dns_server.py

import multiprocessing
import os
import socket
import time

from twisted.python.components import proxyForInterface
from twisted.internet.interfaces import IResolver
from twisted.names import dns, root, server



class PrintingResolver(proxyForInterface(IResolver)):
    def __init__(self, original):
        self.original = original

    def query(self, *args, **kwargs):
        print "QUERY IN CHILD", os.getpid()
        time.sleep(0.1)
        return self.original.query(*args, **kwargs)



def startChild(socketFD, socketFamily):
    from twisted.internet import reactor

    rootAddresses = [
        socket.gethostbyname(d + '.root-servers.net')
        for d in 'abcdefghijklm']

    s = server.DNSServerFactory(
        clients=[
            PrintingResolver(
                root.Resolver(
                    hints=rootAddresses,
                    reactor=reactor))])

    p = dns.DNSDatagramProtocol(controller=s, reactor=reactor)
    reactor.adoptDatagramPort(socketFD, socketFamily,  p)
    reactor.run()
    raise SystemExit()



def main():
    print "PARENT", os.getpid()
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.setblocking(False)
    sock.bind(('127.0.0.1', 10053))
    childpids = []

    for i in range(min(multiprocessing.cpu_count(), 2)):
        pid = os.fork()
        if pid == 0:
            startChild(sock.fileno(), socket.AF_INET)
        else:
            print "CHILD", pid
            childpids.append(pid)

    for pid in childpids:
        os.waitpid(pid, 0)



if __name__ == '__main__':
    main()