#!/usr/bin/env python3
__author__ = 'xtof'
import argparse
import re
import logging
import sys
from subprocess import Popen, PIPE
from docker import Client
from docker.utils import kwargs_from_env
from dns.resolver import Resolver
from dns.exception import DNSException
# Templates for nsupdate
zone_update_start_template = """server {0}
zone {1}.
"""
zone_update_template = """update delete {0}.{1}
update add {0}.{1} 60 A {2}
"""
zone_update_add_alias_template = """update delete {0}.{1}
update add {0}.{1} 600 CNAME {2}.{1}.
update add {2}.{1} 600 TXT dockerDDNS-alias:{0}:
"""
zone_update_delete_record_template = """update delete {0}.{1}
"""
def register_container(container_id):
detail = c.inspect_container(container_id)
container_hostname = detail["Config"]["Hostname"]
container_name = detail["Name"].split('/', 1)[1]
network_mode = detail["HostConfig"]["NetworkMode"]
if network_mode == "default":
container_ip = detail["NetworkSettings"]["IPAddress"]
else :
container_ip = detail["NetworkSettings"]["Networks"][network_mode]["IPAddress"]
logging.info("Updating %s to ip (%s|%s) -> %s", container_id, container_hostname, container_name, container_ip)
if not args.dry_run:
nsupdate = Popen(['nsupdate', '-k', args.key], stdin=PIPE)
nsupdate.stdin.write(bytes(zone_update_start_template.format(args.server, args.zone), "UTF-8"))
nsupdate.stdin.write(bytes(zone_update_template.format(container_hostname, args.domain, container_ip), "UTF-8"))
if container_name != container_hostname:
nsupdate.stdin.write(bytes(zone_update_add_alias_template.format(container_name, args.domain, container_hostname), "UTF-8"))
if re.search("_", container_name):
alternate_name = re.sub('_','-',container_name)
logging.info("Adding alternate name %s to %s", alternate_name, container_name)
nsupdate.stdin.write(bytes(zone_update_add_alias_template.format(alternate_name, args.domain, container_hostname), "UTF-8"))
nsupdate.stdin.write(bytes("send\n", "UTF-8"))
nsupdate.stdin.close()
def remove_container(container_id):
logging.info("Destroying %s", container_id)
short_id = container_id[:12]
record_to_delete = [short_id]
logging.debug("Looking for alias to %s.%s", short_id, args.domain)
try:
answers = resolver.query("{0}.{1}.".format(short_id, args.domain), "TXT", raise_on_no_answer=False).rrset
if answers:
for answer in answers:
logging.debug("Checking TXT record %s for alias", answer)
match = re.search(r"dockerDDNS-alias:([^:]+):", answer.to_text())
if match:
record_to_delete.append(match.group(1))
except DNSException as e:
logging.error("Cannot get TXT record for %s: %s", short_id, e)
except:
logging.error("Unexpected error: %s", sys.exc_info()[0])
raise
if not args.dry_run:
nsupdate = Popen(['nsupdate', '-k', args.key], stdin=PIPE)
nsupdate.stdin.write(bytes(zone_update_start_template.format(args.server, args.zone), "UTF-8"))
for record in record_to_delete:
logging.info("Removing record for %s", record)
nsupdate.stdin.write(bytes(zone_update_delete_record_template.format(record, args.domain), "UTF-8"))
nsupdate.stdin.write(bytes("send\n", "UTF-8"))
nsupdate.stdin.close()
parser = argparse.ArgumentParser()
parser.add_argument("--key", required=True, help="Path to the dynamic dns key")
parser.add_argument("--server", help="IP/Hostname of the server to update", default="127.0.0.1")
parser.add_argument("--domain", help="The domain to be updated", required=True)
parser.add_argument("--zone", help="The zone to be updated (default to the domain)")
parser.add_argument("--dry-run", help="Run in dry run mode without doing any update", default=False, action="store_true")
parser.add_argument("--catchup", help="Register the running containers on startup", default=False, action="store_true")
parser.add_argument("--log-level", help="Log level to display", default="INFO")
parser.add_argument("--log-file", help="Where to put the logs", default="/var/log/docker-ddns.log")
args = parser.parse_args()
logging.basicConfig(level=getattr(logging,args.log_level.upper()),
format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',
filename=(args.log_file if args.log_file != '-' else None))
if args.zone is None:
args.zone = args.domain
logging.info("Starting with arguments %s", args)
c = Client(**(kwargs_from_env()))
resolver = Resolver()
resolver.nameservers = [args.server]
if args.catchup:
logging.info("Registering existing containers")
containers = c.containers()
for container in containers:
register_container(container["Id"])
# TODO use docker-py streaming API
events_pipe = Popen(['docker', 'events'], stdout=PIPE)
while True:
line = events_pipe.stdout.readline()
if line != '':
text_line = line.decode().rstrip()
logging.debug("Read line %s", text_line)
m = re.search(r"\s+([0-9a-f]{64}):.*\s+([a-z]+)\s*$", text_line)
if m:
event = m.group(2)
container_id = m.group(1)
logging.debug("Got event %s for container %s", event, container_id)
if event == "start":
register_container(container_id)
elif event == "destroy":
remove_container(container_id)
else:
print("Done return code: ", events_pipe.returncode)
break
# 2014-11-28T15:32:04.000000000+01:00 a3d66b00acc9adbdbdbc91cc664d2d94b6a07cc4295c5cf54fcc595e2aa92a43: (from mongo:latest) restart
# 2015-03-05T08:36:14.000000000+01:00 eb75c1a5ad836d008b0fd66bf6b1ea353510175e8caa619e59d9851029b1ceca: (from ggtools/zabbix-server:latest) exec_start: ifconfig eth0
