app.py

#!/usr/bin/python3

import os
import CloudFlare
from flask import Flask, request
from flask_httpauth import HTTPBasicAuth
from werkzeug.security import generate_password_hash, check_password_hash

app = Flask(__name__)
auth = HTTPBasicAuth()

# Set variables from environment variables
auth_user = os.environ.get('AUTH_USER', None)
auth_pass = os.environ.get('AUTH_PASS', None)
api_token = os.environ.get('API_TOKEN', None)
record_type = os.environ.get('RECORD_TYPE', 'A')
record_ttl = os.environ.get('RECORD_TTL', 60)

users = {
    auth_user: generate_password_hash(auth_pass)
}

@auth.verify_password
def verify_password(username, password): # pylint: disable=inconsistent-return-statements
    if username in users and check_password_hash(users.get(username), password):
        return username

@auth.error_handler
def unauthorized():
    log_msg('Authentication failed')
    return "badauth"

@app.route('/update')
@app.route('/nic/update')
@auth.login_required
def main():
    # Set hostname variable
    if 'hostname' in request.args:
        hostname = request.args.get('hostname')
    else:
        hostname = 'blank'

    # Set ip variable
    if 'myip' in request.args:
        ip = request.args.get('myip')
    else:
        ip = 'blank'

    # Test inputs to determine the next step
    if hostname == 'blank':
        log_msg('Incoming request did not contain an IP')
        response = "nohost"
    elif ip == 'blank':
        log_msg('Incoming request did not contain an IP')
        response = "noip"
    else:
        log_msg('Received update request for ' + hostname + ' (' + ip + ')')
        response = check_cloudflare(hostname, ip)

    return response

# Cloudflare Functions
def check_cloudflare(hostname, ip):
    # Check if API token is set appropriately
    if api_token not in (None, ''):
        record_name = hostname

        # Determine the DNS zone from the supplied hostname
        hostname_split = hostname.split('.')
        zone_name = '.'.join(hostname_split[1:])

        # Initialize the Cloudflare API
        cf = CloudFlare.CloudFlare(token=api_token)

        # Get the DNS zone ID
        try:
            zones = cf.zones.get(params={'name': zone_name})
            if len(zones) == 0:
                log_msg('Zone ' + zone_name + ' not found')
            zone_id = zones[0]['id']
        except CloudFlare.exceptions.CloudFlareAPIError as e:
            log_msg('/zones.get %d %s' % (e, e)) # pylint: disable=bad-string-format-type, consider-using-f-string

        # Get the DNS record ID
        try:
            dns_records = cf.zones.dns_records.get(zone_id, params={'name': record_name, 'type': record_type})
            if len(dns_records) == 0:
                log_msg('DNS record ' + record_name + ' not found')
            record_id = dns_records[0]['id']
            record_content = dns_records[0]['content']
            record_ttl_current = dns_records[0]['ttl']
        except CloudFlare.exceptions.CloudFlareAPIError as e:
            log_msg('/zones.dns_records.get %d %s' % (e, e)) # pylint: disable=bad-string-format-type, consider-using-f-string

        # Test if the record needs updating
        if record_content != ip or record_ttl_current != record_ttl:
            log_msg("A DNS record update is needed for " + record_name)

            # Update the DNS record
            dns_record = {
                'type': record_type,
                'name': record_name,
                'content': ip,
                'ttl': record_ttl
            }

            try:
                cf.zones.dns_records.put(zone_id, record_id, data=dns_record)
                log_msg('DNS record updated successfully: ' + record_name + ' (' + ip + ')')
                response = "good " + ip
            except CloudFlare.exceptions.CloudFlareAPIError as e:
                log_msg('/zones.dns_records.put %d %s' % (e, e)) # pylint: disable=bad-string-format-type, consider-using-f-string
                response = "dnserr"
        else:
            log_msg('No update needed for ' + hostname + ' (' + ip + ')')
            response = "nochg " + ip
    else:
        log_msg('No api token has been configured for Cloudflare')
        response = "noapitoken"

    return response

def log_msg(msg):
    print(msg)

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=8080, debug=True)