300 lines
13 KiB
Python
Executable File
300 lines
13 KiB
Python
Executable File
#!/usr/bin/env python3
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import argparse
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import json
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import logging
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import logging.handlers
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import os
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import re
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import sys
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import warnings
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##
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import dns.exception
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import dns.resolver
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import requests
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##
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from lxml import etree
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try:
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# https://www.freedesktop.org/software/systemd/python-systemd/journal.html#journalhandler-class
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from systemd import journal
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_has_journald = True
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except ImportError:
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_has_journald = False
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logfile = '~/.cache/ddns.log'
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# Prep the log file.
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logfile = os.path.abspath(os.path.expanduser(logfile))
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os.makedirs(os.path.dirname(logfile), exist_ok = True, mode = 0o0700)
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if not os.path.isfile(logfile):
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with open(logfile, 'w') as fh:
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fh.write('')
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os.chmod(logfile, 0o0600)
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# And set up logging.
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_cfg_args = {'handlers': [],
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'level': logging.DEBUG}
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if _has_journald:
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# There were some weird changes somewhere along the line.
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try:
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# But it's *probably* this one.
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h = journal.JournalHandler()
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except AttributeError:
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h = journal.JournaldLogHandler()
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# Systemd includes times, so we don't need to.
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h.setFormatter(logging.Formatter(style = '{',
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fmt = ('{name}:{levelname}:{name}:{filename}:'
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'{funcName}:{lineno}: {message}')))
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_cfg_args['handlers'].append(h)
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h = logging.handlers.RotatingFileHandler(logfile,
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encoding = 'utf8',
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# Disable rotating for now.
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# maxBytes = 50000000000,
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# backupCount = 30
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)
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h.setFormatter(logging.Formatter(style = '{',
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fmt = ('{asctime}:'
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'{levelname}:{name}:{filename}:'
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'{funcName}:{lineno}: {message}')))
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_cfg_args['handlers'].append(h)
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logging.basicConfig(**_cfg_args)
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logger = logging.getLogger('DDNS')
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logger.info('Logging initialized.')
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is_tty = sys.stdin.isatty()
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if not is_tty:
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logger.debug('Not running in an interactive invocation; disabling printing warnings')
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else:
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logger.debug('Running in an interactive invocation; enabling printing warnings')
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class Updater(object):
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tree = None
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records = {}
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api_base = None
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session = None
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token = None
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my_ips = {4: None, 6: None}
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resolver = dns.resolver.Resolver(configure = False)
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resolver.nameservers = ['64.6.64.6', '64.6.65.6']
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def __init__(self, cfg_path = '~/.config/ddns.xml', *args, **kwargs):
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self.xml = os.path.abspath(os.path.expanduser(cfg_path))
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logger.debug('Updater initialized with config {0}'.format(self.xml))
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self._getConf()
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self._getMyIP()
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self._getSession()
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def _getConf(self):
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try:
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with open(self.xml, 'rb') as fh:
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self.xml = etree.fromstring(fh.read())
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except FileNotFoundError as e:
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logger.error('Configuration file does not exist; please create it')
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raise e
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self.tree = self.xml.getroottree()
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self.token = self.xml.attrib['token']
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self.api_base = re.sub(r'/$', '', self.xml.attrib['base'])
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dom_xml = self.xml.findall('domain')
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num_doms = len(dom_xml)
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logger.debug('Found {0} domains in config'.format(num_doms))
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for idx, d in enumerate(dom_xml):
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domain = d.attrib['name']
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logger.debug('Iterating domain {0} ({1}/{2})'.format(domain, (idx + 1), num_doms))
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if domain not in self.records.keys():
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self.records[domain] = []
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sub_xml = d.findall('sub')
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num_subs = len(sub_xml)
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logger.debug('Found {0} records for domain {1}'.format(num_subs, domain))
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for idx2, s in enumerate(sub_xml):
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logger.debug('Adding record {0}.{1} to index ({2}/{3})'.format(s.text, domain, (idx2 + 1), num_subs))
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self.records[domain].append(s.text)
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return()
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def _getDNS(self, record):
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records = {}
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for t in ('A', 'AAAA'):
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logger.debug('Resolving {0} ({1})'.format(record, t))
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try:
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q = self.resolver.query(record, t)
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for a in q:
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if t not in records.keys():
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records[t] = []
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ip = a.to_text()
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logger.debug('Found IP {0} for record {1} ({2})'.format(ip, record, t))
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records[t].append(ip)
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except dns.exception.Timeout as e:
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logger.error('Got a timeout when resolving {0} ({1}): {2}'.format(record, t, e))
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continue
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except dns.resolver.NXDOMAIN as e:
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# This is a debug instead of an error because that record type may not exist.
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logger.debug('Record {0} ({1}) does not exist: {2}'.format(record, t, e))
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continue
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except dns.resolver.YXDOMAIN as e:
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logger.error('Record {0} ({1}) is too long: {2}'.format(record, t, e))
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continue
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except dns.resolver.NoAnswer as e:
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# This is a debug instead of an error because that record type may not exist.
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logger.debug('Record {0} ({1}) exists but has no content: {2}'.format(record, t, e))
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continue
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except dns.resolver.NoNameservers as e:
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logger.error(('Could not failover to a non-broken resolver when resolving {0} ({1}): '
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'{2}').format(record, t, e))
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continue
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return(records)
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def _getMyIP(self):
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for v in self.my_ips.keys():
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try:
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logger.debug('Getting the client\'s WAN address for IPv{0}'.format(v))
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r = requests.get('https://ipv{0}.clientinfo.square-r00t.net/?raw=1'.format(v))
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if not r.ok:
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logger.error('Got a non-OK response from WAN IPv{0} fetch.'.format(v))
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raise RuntimeError('Could not get the IPv{0} address'.format(v))
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ip = r.json()['ip']
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logger.debug('Got WAN IP address {0} for IPv{1}'.format(ip, v))
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self.my_ips[v] = ip
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except requests.exceptions.ConnectionError:
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logger.debug('Could not get WAN address for IPv{0}; likely not supported on this network'.format(v))
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return()
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def _getSession(self):
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self.session = requests.Session()
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self.session.headers.update({'Authorization': 'Bearer {0}'.format(self.token)})
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return()
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def update(self):
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for d in self.records.keys():
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d_f = json.dumps({'domain': d})
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doms_url = '{0}/domains'.format(self.api_base)
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logger.debug('Getting list of domains from {0} (filtered to {1})'.format(doms_url, d))
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d_r = self.session.get(doms_url,
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headers = {'X-Filter': d_f})
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if not d_r.ok:
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e = 'Could not get list of domains when attempting to check {0}; skipping'.format(d)
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if is_tty:
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warnings.warn(e)
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logger.warning(e)
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continue
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try:
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d_id = d_r.json()['data'][0]['id']
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except (IndexError, KeyError):
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e = 'Could not find domain {0} in the returned domains list; skipping'.format(d)
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if is_tty:
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warnings.warn(e)
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logger.warning(e)
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continue
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for s in self.records[d]:
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fqdn = '{0}.{1}'.format(s, d)
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logger.debug('Processing {0}'.format(fqdn))
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records = self._getDNS(fqdn)
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for v, t in ((4, 'A'), (6, 'AAAA')):
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ip = self.my_ips.get(v)
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rrset = records.get(t)
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if not ip:
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e = 'IPv{0} disabled; skipping'.format(v)
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if is_tty:
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warnings.warn(e)
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logger.warning(e)
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continue
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if rrset and ip in rrset:
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e = 'Skipping adding {0} for {1}; already exists in DNS'.format(ip, fqdn)
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logger.info(e)
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if is_tty:
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print(e)
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continue
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s_f = json.dumps({'name': s,
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'type': t})
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records_url = '{0}/domains/{1}/records'.format(self.api_base, d_id)
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logger.debug(('Getting list of records from {0} '
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'(filtered to name {1} and type {2})').format(records_url, s, t))
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s_r = self.session.get(records_url,
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headers = {'X-Filter': s_f})
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if not s_r.ok:
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e = 'Could not get list of records when attempting to check {0} ({1}); skipping'.format(fqdn, t)
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if is_tty:
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warnings.warn(e)
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logger.warning(e)
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continue
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r_ids = set()
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# If r_exists is:
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# None, then the record exists but the current WAN IP is missing (all records replaced).
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# False, then the record does not exist (record will be added).
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# True, then the record exists and is current (nothing will be done).
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r_exists = None
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try:
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api_records = s_r.json().pop('data')
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for idx, r in enumerate(api_records):
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r_ids.add(r['id'])
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r_ip = r['target']
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if r_ip == ip:
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r_exists = True
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except (IndexError, KeyError):
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e = ('Could not find record {0} ({1}) in the returned records list; '
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'creating new record').format(fqdn, t)
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if is_tty:
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print(e)
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logger.info(e)
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r_exists = False
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if r_exists:
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# Do nothing.
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e = 'Skipping adding {0} for {1}; already exists in API and is correct'.format(ip, fqdn)
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logger.info(e)
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if is_tty:
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print(e)
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continue
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elif r_exists is None:
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# Remove all records and then add (at the end).
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# We COULD do an update:
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# https://developers.linode.com/api/v4/domains-domain-id-records-record-id/#put
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# BUT then we break future updating since we don't know which record is the "right" one to
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# update.
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logger.debug('Record {0} ({1}) exists but does not contain {2}; replacing'.format(fqdn, t, ip))
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for r_id in r_ids:
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del_url = '{0}/{1}'.format(records_url, r_id)
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logger.debug(('Deleting record ID {0} for {1} ({2})').format(r_id, fqdn, t))
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del_r = self.session.delete(del_url)
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if not del_r.ok:
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e = 'Could not delete record ID {0} for {1} ({2}); skipping'.format(r_id, fqdn, t)
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if is_tty:
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warnings.warn(e)
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logger.warning(e)
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continue
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else:
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# Create the record.
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logger.debug('Record {0} ({1}) does not exist; creating'.format(fqdn, ip))
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record = {'name': s,
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'type': t,
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'target': ip,
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'ttl_sec': 300}
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create_r = self.session.post(records_url,
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json = record)
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if not create_r.ok:
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e = 'Could not create record {0} ({1}); skipping'.format(fqdn, t)
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if is_tty:
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warnings.warn(e)
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logger.warning(e)
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continue
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return()
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def parseArgs():
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args = argparse.ArgumentParser(description = ('Automatically update Linode DNS via their API'))
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args.add_argument('-c', '--config',
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dest = 'cfg_path',
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default = '~/.config/ddns.xml',
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help = ('The path to the configuration file. Default: ~/.config/ddns.xml'))
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return(args)
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def main():
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args = parseArgs().parse_args()
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u = Updater(**vars(args))
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u.update()
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return(None)
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if __name__ == '__main__':
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main()
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