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# Copyright 2014 Rackspace Inc.
#
# Author: Tim Simmons <tim.simmons@rackspace.com>
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""
backend.agent
~~~~~~~~~~~~~
Agent backend for Pool Manager.
Sends DNS requests to a remote agent using private OPCODEs to trigger
creation / deletion / update of zones.
Configured in the [service:pool_manager] section
"""
import dns
import dns.exception
import dns.flags
import dns.message
import dns.opcode
import dns.rcode
import dns.rdataclass
import dns.rdatatype
from oslo_config import cfg
from oslo_log import log as logging
from designate.backend import base
from designate.backend import private_codes
from designate.conf.agent import DEFAULT_AGENT_PORT
from designate import dnsutils
from designate import exceptions
LOG = logging.getLogger(__name__)
CONF = cfg.CONF
class AgentPoolBackend(base.Backend):
__plugin_name__ = 'agent'
__backend_status__ = 'untested'
def __init__(self, target):
super(AgentPoolBackend, self).__init__(target)
self.host = self.options.get('host', '127.0.0.1')
self.port = int(self.options.get('port', DEFAULT_AGENT_PORT))
self.timeout = CONF['service:worker'].poll_timeout
self.retry_interval = CONF['service:worker'].poll_retry_interval
self.max_retries = CONF['service:worker'].poll_max_retries
# FIXME: the agent retries creating zones without any interval
def create_zone(self, context, zone):
LOG.debug('Create Zone')
response = self._make_and_send_dns_message(
zone.name,
self.timeout,
private_codes.CC,
private_codes.CREATE,
private_codes.CLASSCC,
self.host,
self.port
)
if response is None:
raise exceptions.Backend('Failed create_zone()')
def update_zone(self, context, zone):
LOG.debug('Update Zone')
def delete_zone(self, context, zone):
LOG.debug('Delete Zone')
response = self._make_and_send_dns_message(
zone.name,
self.timeout,
private_codes.CC,
private_codes.DELETE,
private_codes.CLASSCC,
self.host,
self.port
)
if response is None:
raise exceptions.Backend('Failed delete_zone()')
def _make_and_send_dns_message(self, zone_name, timeout, opcode,
rdatatype, rdclass, dest_ip,
dest_port):
dns_message = self._make_dns_message(
zone_name, opcode, rdatatype, rdclass
)
LOG.info(
"Sending '%(msg)s' for '%(zone)s' to '%(server)s:%(port)d'.",
{
'msg': str(opcode),
'zone': zone_name,
'server': dest_ip,
'port': dest_port
}
)
try:
response = dnsutils.send_dns_message(
dns_message, dest_ip, port=dest_port, timeout=timeout
)
# Check that we actually got a NOERROR in the rcode and and an
# authoritative answer
if not (response.flags & dns.flags.AA) or dns.rcode.from_flags(
response.flags, response.ednsflags) != dns.rcode.NOERROR:
LOG.warning(
"Failed to get expected response while trying to "
"send '%(msg)s' for '%(zone)s' to "
"'%(server)s:%(port)d'. Response message: %(resp)s",
{
'msg': str(opcode),
'zone': zone_name,
'server': dest_ip,
'port': dest_port,
'resp': str(response)
}
)
response = None
except dns.exception.Timeout:
LOG.warning(
"Got Timeout while trying to send '%(msg)s' for "
"'%(zone)s' to '%(server)s:%(port)d'. "
"Timeout='%(timeout)d' seconds.",
{
'msg': str(opcode),
'zone': zone_name,
'server': dest_ip,
'port': dest_port,
'timeout': timeout,
}
)
response = None
except dns.query.BadResponse:
LOG.warning(
"Got BadResponse while trying to send '%(msg)s' for "
"'%(zone)s' to '%(server)s:%(port)d'. "
"Timeout='%(timeout)d' seconds.",
{
'msg': str(opcode),
'zone': zone_name,
'server': dest_ip,
'port': dest_port,
'timeout': timeout,
}
)
response = None
return response
@staticmethod
def _make_dns_message(zone_name, opcode, rdatatype, rdclass):
dns_message = dns.message.make_query(zone_name, rdatatype,
rdclass=rdclass)
dns_message.flags = 0
dns_message.set_opcode(opcode)
dns_message.flags |= dns.flags.AA
return dns_message
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