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dns/generateZonefiles.py
Knut Ahlers 2fd806a998
Remove code duplication by using mailserver sets
Signed-off-by: Knut Ahlers <knut@ahlers.me>
2018-02-18 13:49:51 +01:00

150 lines
3.7 KiB
Python

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import difflib
import hashlib
import os
import os.path
import sys
import time
# Third-party imports
import dns.resolver
import dns.rdatatype
import jinja2
import yaml
DEFAULT_TTL = 3600
def default(d, key, default=None):
if key in d:
return d[key]
return default
def diff_files(file1, file2):
fromlines = []
tolines = []
if os.path.isfile(file1):
with open(file1) as ff:
fromlines = ff.readlines()
if os.path.isfile(file2):
with open(file2) as tf:
tolines = tf.readlines()
print(''.join(difflib.unified_diff(
fromlines, tolines, file1, file2)))
def hash_file(filename):
if not os.path.isfile(filename):
return ""
hasher = hashlib.sha1()
with open(filename, 'r') as afile:
lines = afile.readlines()
lines = map(replace_soa_line, lines)
hasher.update(''.join(lines).encode('utf-8'))
return hasher.hexdigest()
def replace_soa_line(line):
if 'SOA' in line:
return '; SOA line replaced'
return line
def resolve_alias(entry):
result = []
answers = []
answers.extend(dns.resolver.query(
entry['alias'], 'A', raise_on_no_answer=False))
answers.extend(dns.resolver.query(
entry['alias'], 'AAAA', raise_on_no_answer=False))
if len(answers) == 0:
raise Exception(
"Alias {} was not resolvable: No answers!".format(entry['alias']))
for rdata in answers:
new_entry = entry.copy()
del new_entry['alias']
new_entry['type'] = dns.rdatatype.to_text(rdata.rdtype)
new_entry['data'] = rdata.address
result.append(new_entry)
return sorted(result, key=lambda k: k['data'])
def sanitize(entry):
result = []
if entry['name'] == '':
entry['name'] = '@'
if 'alias' in entry:
return resolve_alias(entry)
for rr in entry['records']:
new_entry = entry.copy()
del new_entry['records']
new_entry['data'] = rr
if new_entry['type'] == 'TXT' and new_entry['data'][0] != '"':
new_entry['data'] = '"{}"'.format(new_entry['data'])
result.append(new_entry)
result.sort(key=lambda k: k['data'])
return result
def write_zone(zone, ttl, soa, nameserver, mailserver, entries):
soa['serial'] = int(time.time()) - 946681200 # 2000-01-01
tpl = jinja2.Template(open("zone_template.j2").read())
zone_content = tpl.render({
"zone": zone,
"ttl": ttl,
"soa": soa,
"nameserver": nameserver,
"mailserver": mailserver,
"entries": entries,
})
with open("zones/tmp.{}".format(zone), 'w') as zf:
zf.write(zone_content)
if hash_file("zones/tmp.{}".format(zone)) != hash_file("zones/db.{}".format(zone)):
print("Generated and replaced zone file for {}".format(zone))
diff_files("zones/db.{}".format(zone), "zones/tmp.{}".format(zone))
os.rename("zones/tmp.{}".format(zone), "zones/db.{}".format(zone))
else:
os.unlink("zones/tmp.{}".format(zone))
def main():
zone_data = yaml.load(open("zones.yml"))
for zone, config in zone_data['zones'].items():
ttl = default(config, "default_ttl", DEFAULT_TTL)
entries = []
for entry in default(config, 'entries', []):
entries.extend(sanitize(entry))
mailserver = default(config, 'mailserver', {})
if 'mailserver_set' in config and config['mailserver_set'] in zone_data['mailserver_sets']:
mailserver = zone_data['mailserver_sets'][config['mailserver_set']]
write_zone(zone, ttl, zone_data['soa'],
zone_data['nameserver'], mailserver, entries)
if __name__ == "__main__":
main()