def __init__(self,routes,origin,ttl):
self.origin = DNSLabel(origin)
self.ttl = parse_time(ttl)
self.routes = {}
for r in routes:
route,_,cmd = r.partition(":")
if route.endswith('.'):
route = DNSLabel(route)
else:
route = self.origin.add(route)
self.routes[route] = cmd
class ShellResolver(BaseResolver):
"""
Example dynamic resolver.
Maps DNS labels to shell commands and returns result as TXT record
(Note: No context is passed to the shell command)
Shell commands are passed in a a list in <label>:<cmd> format - eg:
[ 'uptime.abc.com.:uptime', 'ls:ls' ]
Would respond to requests to 'uptime.abc.com.' with the output
of the 'uptime' command.
For non-absolute labels the 'origin' parameter is prepended
"""
def __init__(self,routes,origin,ttl):
self.origin = DNSLabel(origin)
self.ttl = parse_time(ttl)
self.routes = {}
for r in routes:
route,_,cmd = r.partition(":")
if route.endswith('.'):
route = DNSLabel(route)
else:
route = self.origin.add(route)
self.routes[route] = cmd
def resolve(self,request,handler):
reply = request.reply()
qname = request.q.qname
cmd = self.routes.get(qname)
if cmd:
output = getoutput(cmd).encode()
reply.add_answer(RR(qname,QTYPE.TXT,ttl=self.ttl,
rdata=TXT(output[:254])))
else:
reply.header.rcode = RCODE.NXDOMAIN
return reply
