Script to update DNS entries for a list of domains via GlySYS API.

dynamicdns.py

#!/usr/bin/env python3
"""
Script to update DNS entries for a list of domains via GlySYS API.
"""

import argparse
import ipaddress
import logging
import os
import requests

from logging.handlers import RotatingFileHandler


# Set variables.
apikey = 'CHANGE_THIS_to_your_api_key'
apiurl = 'https://api.glesys.com/domain/updaterecord/'
apiuser = 'CHANGE_THIS_to_your_api_user'
current_ip_file = '/var/spool/dynamicdns/current_ip.txt'
dns_records = {
    '12345': 'example.org',
    '23456': 'vpn.example.org',
    '34567': 'server.example.org',
}


def logger():
    logfile = '/var/log/dynamicdns.log'
    log_format = ('%(asctime)s %(levelname)-8s %(message)s')
    logging.basicConfig(
        level=logging.INFO,
        format=log_format,
        handlers=[
            RotatingFileHandler(logfile, maxBytes=50000)
        ],
    )
    return logging.getLogger(__name__)


logger = logger()


def updatedns(recordid, new_ip_address):
    r = requests.post(apiurl, auth=(apiuser, apikey), headers={'accept': 'application/json'}, data={'recordid': recordid, 'data': new_ip_address})
    output = r.json()
    response_code = output['response']['status']['code']
    response_text = output['response']['status']['text']
    response_ip = output['response']['record']['data']
    if response_code == 200:
        logger.info(f'{dns_records[recordid]} has been updated to IP {response_ip}')
    else:
        logger.error(f'{dns_records[recordid]} could not be updated Error code: {response_code} {response_text}')


def get_current_ip():
    current_ip = None
    try:
        with open(current_ip_file, 'r') as f:
            current_ip = f.read()
    except FileNotFoundError:
        pass
    return current_ip


def set_current_ip(new_ip_address):
    os.makedirs(os.path.dirname(current_ip_file), exist_ok=True)
    with open(current_ip_file, 'w') as f:
        f.write(new_ip_address)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('new_ip_address', type=str, help='The new IP address.')
    args = parser.parse_args()
    new_ip_address = args.new_ip_address

    try:
        ipaddress.ip_address(new_ip_address)
    except ValueError:
        logger.warning(f'Not a valid new IP: {new_ip_address}')
    else:
        if new_ip_address != get_current_ip():
            set_current_ip(new_ip_address)
            [updatedns(recordid, new_ip_address) for recordid in dns_records]


if __name__ == '__main__':
    main()