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Python/Twisted/Redis backed DNS server.
# Python/Twisted/Redis backed DNS server - resolves from NAME to IP addrs
# fallback to google or any other DNS server to resolv domains not present on Redis
# to set a new domain on redis, just issue a SET domain.tld ip_addr
# run with twistd -ny txredns.tac
# gleicon 2011
from twisted.names import dns, server, client, cache
from twisted.application import service, internet
from twisted.internet import defer
from twisted.python import log
import txredisapi
class RedisResolverBackend(client.Resolver):
def __init__(self, redis, servers=None):
self.redis = redis
client.Resolver.__init__(self, servers=servers)
self.ttl = 5
@defer.inlineCallbacks
def _get_ip_addr(self, hostname, timeout):
ip = yield self.redis.get(hostname)
log.msg('redis: %s'% ip)
r = None
if ip:
defer.returnValue([(dns.RRHeader(hostname, dns.A, dns.IN, self.ttl, dns.Record_A(ip, self.ttl)),), (), ()])
else:
i = yield self._lookup(hostname, dns.IN, dns.A, timeout)
defer.returnValue(i)
def lookupAddress(self, name, timeout = None):
return self._get_ip_addr(name, timeout)
def create_application():
rd = txredisapi.lazyRedisConnectionPool()
redisBackend = RedisResolverBackend(rd, servers=[('8.8.8.8', 53)])
application = service.Application("txdnsredis")
srv_collection = service.IServiceCollection(application)
dnsFactory = server.DNSServerFactory(caches=[cache.CacheResolver()], clients=[redisBackend])
internet.TCPServer(53, dnsFactory).setServiceParent(srv_collection)
internet.UDPServer(53, dns.DNSDatagramProtocol(dnsFactory)).setServiceParent(srv_collection)
return application
# .tac app
application = create_application()
@fnando

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@fnando fnando commented Jul 10, 2011

Sweet! :D

@mikeifomin

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@mikeifomin mikeifomin commented Aug 27, 2013

Simple and cool!

@stefanfoulis

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@stefanfoulis stefanfoulis commented Mar 25, 2014

I'd like to flesh out the code a bit and release it on pypi.
(and later make backends pluggable, e.g for plainfiles and etcd).

@gleicon Is it ok for you if I release it under the BSD license?

@gleicon

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Owner Author

@gleicon gleicon commented Mar 25, 2014

I've answered through email but I'll copy here: ok to use, let me know if you need any help or info. Check out the full repo: https://github.com/gleicon/python_dns_servers. Thanks

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