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# Copyright 2014 eBay Inc.
#
# Author: Ron Rickard <rrickard@ebay.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.
"""
Bind 9 backend. Create and delete zones by executing rndc
"""
import random
import subprocess
from oslo_log import log as logging
from oslo_utils import strutils
from designate import exceptions
from designate import utils
from designate.backend import base
from designate.conf.mdns import DEFAULT_MDNS_PORT
LOG = logging.getLogger(__name__)
DEFAULT_MASTER_PORT = DEFAULT_MDNS_PORT
class Bind9Backend(base.Backend):
__plugin_name__ = 'bind9'
__backend_status__ = 'integrated'
def __init__(self, target):
super(Bind9Backend, self).__init__(target)
self._host = self.options.get('host', '127.0.0.1')
self._port = int(self.options.get('port', 53))
self._view = self.options.get('view')
# Removes zone files when a zone is deleted.
# This option will take effect on bind>=9.10.0.
self._clean_zonefile = strutils.bool_from_string(
self.options.get('clean_zonefile', 'false'))
self._rndc_call_base = self._generate_rndc_base_call()
self._rndc_timeout = self.options.get('rndc_timeout', None)
if self._rndc_timeout == 0:
self._rndc_timeout = None
def _generate_rndc_base_call(self):
"""Generate argument list to execute rndc"""
rndc_host = self.options.get('rndc_host', '127.0.0.1')
rndc_port = int(self.options.get('rndc_port', 953))
rndc_bin_path = self.options.get('rndc_bin_path', 'rndc')
rndc_config_file = self.options.get('rndc_config_file')
rndc_key_file = self.options.get('rndc_key_file')
rndc_call = [rndc_bin_path, '-s', rndc_host, '-p', str(rndc_port)]
if rndc_config_file:
rndc_call.extend(['-c', rndc_config_file])
if rndc_key_file:
rndc_call.extend(['-k', rndc_key_file])
return rndc_call
def create_zone(self, context, zone):
"""Create a new Zone by executin rndc, then notify mDNS
Do not raise exceptions if the zone already exists.
"""
LOG.debug('Create Zone')
masters = []
for master in self.masters:
host = master['host']
port = master['port']
masters.append('%s port %s' % (host, port))
# Ensure different MiniDNS instances are targeted for AXFRs
random.shuffle(masters)
view = 'in %s' % self._view if self._view else ''
rndc_op = [
'addzone',
'%s %s { type slave; masters { %s;}; file "slave.%s%s"; };' %
(zone['name'].rstrip('.'), view, '; '.join(masters), zone['name'],
zone['id']),
]
try:
self._execute_rndc(rndc_op)
except exceptions.Backend as e:
# If create fails because the zone exists, don't reraise
if "already exists" not in str(e):
LOG.warning('RNDC call failure: %s', e)
raise
self.mdns_api.notify_zone_changed(
context, zone, self._host, self._port, self.timeout,
self.retry_interval, self.max_retries, self.delay)
def get_zone(self, context, zone):
"""Returns True if zone exists and False if not"""
LOG.debug('Get Zone')
view = 'in %s' % self._view if self._view else ''
rndc_op = [
'showzone',
'%s %s' % (zone['name'].rstrip('.'), view),
]
try:
self._execute_rndc(rndc_op)
except exceptions.Backend as e:
if "not found" in str(e):
LOG.debug('Zone %s not found on the backend', zone['name'])
return False
else:
LOG.warning('RNDC call failure: %s', e)
raise e
return True
def delete_zone(self, context, zone):
"""Delete a new Zone by executin rndc
Do not raise exceptions if the zone does not exist.
"""
LOG.debug('Delete Zone')
view = 'in %s' % self._view if self._view else ''
rndc_op = [
'delzone',
'%s %s' % (zone['name'].rstrip('.'), view),
]
if self._clean_zonefile:
rndc_op.insert(1, '-clean')
try:
self._execute_rndc(rndc_op)
except exceptions.Backend as e:
# If zone is already deleted, don't reraise
if "not found" not in str(e):
LOG.warning('RNDC call failure: %s', e)
raise
def update_zone(self, context, zone):
"""
Update a DNS zone.
This will execute a rndc modzone if the zone
already exists but masters might need to be refreshed.
Or, will create the zone if it does not exist.
:param context: Security context information.
:param zone: the DNS zone.
"""
LOG.debug('Update Zone')
if not self.get_zone(context, zone):
# If zone does not exist yet, create it
self.create_zone(context, zone)
# Newly created zone won't require an update
return
masters = []
for master in self.masters:
host = master['host']
port = master['port']
masters.append('%s port %s' % (host, port))
# Ensure different MiniDNS instances are targeted for AXFRs
random.shuffle(masters)
view = 'in %s' % self._view if self._view else ''
rndc_op = [
'modzone',
'%s %s { type slave; masters { %s;}; file "slave.%s%s"; };' %
(zone['name'].rstrip('.'), view, '; '.join(masters), zone['name'],
zone['id']),
]
try:
self._execute_rndc(rndc_op)
except exceptions.Backend as e:
LOG.warning("Error updating zone: %s", e)
pass
super().update_zone(context, zone)
def _execute_rndc(self, rndc_op):
"""Execute rndc
:param rndc_op: rndc arguments
:type rndc_op: list
:returns: None
:raises: exceptions.Backend
"""
try:
rndc_call = self._rndc_call_base + rndc_op
LOG.debug('Executing RNDC call: %r with timeout %s',
rndc_call, self._rndc_timeout)
utils.execute(*rndc_call, timeout=self._rndc_timeout)
except (utils.processutils.ProcessExecutionError,
subprocess.TimeoutExpired) as e:
raise exceptions.Backend(e)
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