Question

I’d like to know why the following doesn’t work.

from twisted internet import defer, reactor
from twisted.python.failure import Failure
import twisted.names.client

def do_lookup(do_lookup):
    d = twisted.names.client.getHostByName(domain)
    d.addBoth(lookup_done)

def lookup_done(result):
    print 'result:', result
    reactor.stop()

domain = 'twistedmatrix.com'    
reactor.callLater(0, do_lookup, domain) 
reactor.run()

Results in:

result: [Failure instance: Traceback
(failure with no frames): <class
'twisted.names.error.ResolverError'>:
Stuck at response without answers or
delegation ]

Answer 1

Correcting your example to the following, so that it is syntactically valid:

from twisted.internet import reactor
import twisted.names.client

def do_lookup(domain):
    d = twisted.names.client.getHostByName(domain)
    d.addBoth(lookup_done)

def lookup_done(result):
    print 'result:', result
    reactor.stop()

domain = 'twistedmatrix.com'
reactor.callLater(0, do_lookup, domain)
reactor.run()

I get:

$ python so-example.py 
result: 66.35.39.65

So, to answer your question: your local DNS environment is broken, not twisted.names. Or maybe there’s a bug. You’ll need to track it down further.