Add DDNS service to the Pi

roles/cloudflare-ddns/files/cloudflare_ddns/cloudflare_api.py

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+import requests
+import logging
+
+class CloudflareAPIException(Exception):
+    def __init__(self, message, response) -> None:
+        full_message = f'Cloudflare request failed (code: {response.status_code}): {message}\n\nServer body:\n{response.text}'
+        super().__init__(full_message)
+
+class CloudFlare:
+    def __init__(self, api_token):
+        self.headers = {'Content-Type': 'application/json', 'Authorization': f'Bearer {api_token}'}
+
+    def get_zone_id(self, domain):
+        response = requests.get(f'https://api.cloudflare.com/client/v4/zones?name={domain}', headers=self.headers)
+
+        if response.status_code != 200:
+            raise CloudflareAPIException('Something went wrong requesting the zone of the domain on Cloudflare...', response)
+
+        zone_id = response.json()['result'][0]['id']
+        return zone_id
+
+    def get_record_id(self, zoneId, record):
+        logging.debug('Getting record id...')
+        response = requests.get(f'https://api.cloudflare.com/client/v4/zones/{zoneId}/dns_records?name={record}', headers=self.headers)
+
+        if response.status_code != 200:
+            raise CloudflareAPIException('Something went wrong requesting the record id of the domain name on Cloudflare...', response)
+
+        return response.json()['result'][0]['id']
+
+
+    def change_record(self, subdomain, zoneId, recordId, targetIp):
+        logging.info(f'Changing record for {subdomain} to point to {targetIp}...')
+        response = requests.put(f'https://api.cloudflare.com/client/v4/zones/{zoneId}/dns_records/{recordId}',
+                        headers=self.headers,
+                        json={
+                            'content': targetIp,
+                            'name': subdomain,
+                            'proxied': False,
+                            'type': 'A',
+                            'comment': 'Is set to change with my DDNS script (on the Raspberry Pi).',
+                            'ttl': 1 # Meaning "Automatic", see: https://developers.cloudflare.com/api/operations/dns-records-for-a-zone-update-dns-record
+                        })
+
+        if response.status_code != 200:
+            raise CloudflareAPIException('Something went wrong updating the dns record...', response)
+
+        logging.info('Succesfully updated the record ✅!')

roles/cloudflare-ddns/files/cloudflare_ddns/cloudflare_ddns.py

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+#!/usr/bin/python3
+# Fetches the public IP and updates the record on Cloudflare which is provided as an argument
+# to match this public record.
+import logging
+import sys
+import configparser
+import argparse
+from cloudflare_api import CloudFlare
+from ip_helpers import get_public_IP, resolve_name
+
+
+logging.basicConfig(stream=sys.stdout, level=logging.INFO, format='%(levelname)s - %(message)s')
+
+parser = argparse.ArgumentParser()
+parser.add_argument('subdomains', nargs='+')
+parser.add_argument('-c', '--config-file', dest='config')
+
+args = parser.parse_args()
+
+
+config_file_path = args.config
+
+config = configparser.ConfigParser()
+config.read(config_file_path)
+
+cloudflare_api_credentials = config['credentials']['dns_cloudflare_token']
+cloudflare = CloudFlare(cloudflare_api_credentials)
+
+log_path = config.get('log_changes', 'log_path', fallback=None)
+if log_path is not None:
+    log_path = config['log_changes']['log_path']
+    logging.info(f'Logging DNS name changes to {log_path} on IP updates.')
+
+publicIP = get_public_IP()
+subdomains = args.subdomains
+fixedTopLevelDomain = 'kleinendorst.info'
+
+for subdomain in subdomains:
+    fullDomainName = f'{subdomain}.{fixedTopLevelDomain}'
+
+    resolvedIP = resolve_name(fullDomainName)
+    if resolvedIP == publicIP:
+        logging.info(f'Currently resolved name already matches the public ip ({publicIP}), skipping this name...')
+        continue
+
+    zoneId = cloudflare.get_zone_id(fixedTopLevelDomain)
+    recordId = cloudflare.get_record_id(zoneId, fullDomainName)
+    cloudflare.change_record(subdomain, zoneId, recordId, publicIP)
+
+    with open(log_path, 'a+') as log_file:
+        msg = f'Address for FQDN {fullDomainName} altered from: {resolvedIP} - {publicIP}.'
+        logging.info(f'Writing: "{msg}" to log file at {log_path}...')
+        log_file.write(msg + '\n')

roles/cloudflare-ddns/files/cloudflare_ddns/cloudflare_ddns.sh

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+#!/usr/bin/bash
+source ~/bin/cloudflare_ddns/venv/bin/activate
+python3 ~/bin/cloudflare_ddns/cloudflare_ddns.py --config-file ~/cloudflare_ddns/ddns_config.ini $@

roles/cloudflare-ddns/files/cloudflare_ddns/ip_helpers.py

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+import logging
+import requests
+import dns.resolver
+
+
+def get_public_IP():
+    logging.info('Retrieving the public IP for this machine...')
+    response = requests.get('https://api.ipify.org?format=json')
+
+    if response.status_code != 200:
+        raise Exception('Something went wrong requesting the public ip, exiting...')
+
+    public_ip = response.json()['ip']
+    logging.info(f'The public IP address for this machine is: {public_ip}.')
+    return public_ip
+
+def resolve_name(domain):
+    logging.info(f'Resolving {domain}...')
+    try:
+        result = dns.resolver.resolve(domain, 'A')
+    except dns.resolver.NXDOMAIN:
+        logging.error(f'No DNS record exists for {domain}, configure it first before using this ddns script. Exiting...')
+        exit(1)
+
+    resolved_address = result[0].address
+    logging.info(f'Resolved {domain} to: {resolved_address}.')
+    return resolved_address

roles/cloudflare-ddns/files/cloudflare_ddns/requirements.txt

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+requests==2.31.0
+dnspython==2.6.1