nixos/kelder: Finish upgrade (add ddclient replacement)

nixos/boxes/kelder/dns_update.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+import argparse
+import json
+import subprocess
+
+import CloudFlare
+
+def main():
+    parser = argparse.ArgumentParser(description='Cloudflare DNS update script')
+    parser.add_argument('-k', '--api-token-file', help='Cloudflare API token file')
+    parser.add_argument('zone', help='Cloudflare Zone')
+    parser.add_argument('record', help='Cloudflare record name')
+    parser.add_argument('iface', help='Network interface to grab IP from')
+    args = parser.parse_args()
+
+    cf_token = None
+    if args.api_token_file:
+        with open(args.api_token_file) as f:
+            cf_token = f.readline().strip()
+
+    cf = CloudFlare.CloudFlare(token=cf_token)
+    zones = cf.zones.get(params={'name': args.zone})
+    assert zones, f'Zone {args.zone} not found'
+    records = cf.zones.dns_records.get(zones[0]['id'], params={'name': args.record})
+    assert records, f'Record {args.record} not found in zone {args.zone}'
+
+
+    ip_info = json.loads(subprocess.check_output(
+        ['ip', '-j', 'addr', 'show', 'dev', args.iface], encoding='utf8'))
+    for a_info in ip_info[0]['addr_info']:
+        if a_info['family'] == 'inet' and a_info['scope'] == 'global':
+            address = a_info['local']
+            break
+    else:
+        assert False, f'No usable IP address found on interface {args.iface}'
+
+    print(f'Updating {args.record} -> {address}')
+    cf.zones.dns_records.patch(
+        zones[0]['id'], records[0]['id'],
+        data={'type': 'A', 'name': args.record, 'content': address})
+
+if __name__ == '__main__':
+    main()