Integrate DDNS registration and IP update into installer

setup_cell.py: register_with_ddns() called at end of setup — detects public IP via api.ipify.org, generates TOTP code from DDNS_TOTP_SECRET, POSTs to DDNS /register, saves token to data/api/.ddns_token (mode 600). Idempotent: skips if token file already exists. Fails gracefully if DDNS_TOTP_SECRET is unset or network is unreachable. scripts/ddns_update.py: standalone script for periodic IP updates. Reads token from data/api/.ddns_token, fetches current public IP, compares to cached last IP (data/api/.ddns_last_ip) and calls /update only when the IP has actually changed. Makefile: add ddns-update (run update script) and ddns-register (force re-registration by removing old token then calling register_with_ddns). Usage: DDNS_TOTP_SECRET=<secret> make ddns-register Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-10 02:28:02 -04:00
parent 15376b67c7
commit ffe1dbeed6
3 changed files with 172 additions and 1 deletions
@@ -0,0 +1,86 @@
+#!/usr/bin/env python3
+"""
+Update the cell's DDNS record with the current public IP.
+
+Called by: make ddns-update
+           systemd timer (optional, see scripts/pic-ddns-update.timer)
+
+Reads the DDNS token from data/api/.ddns_token (written by setup_cell.py).
+Exits 0 on success or if already up to date, non-zero on failure.
+"""
+import json
+import os
+import sys
+import urllib.error
+import urllib.request
+
+DDNS_URL = os.environ.get('DDNS_URL', 'https://ddns.pic.ngo/api/v1')
+ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+TOKEN_FILE = os.path.join(ROOT, 'data', 'api', '.ddns_token')
+IP_CACHE_FILE = os.path.join(ROOT, 'data', 'api', '.ddns_last_ip')
+
+
+def get_public_ip() -> str:
+    return urllib.request.urlopen('https://api.ipify.org', timeout=5).read().decode().strip()
+
+
+def read_token() -> str:
+    if not os.path.exists(TOKEN_FILE):
+        print('ERROR: DDNS token not found. Run "make setup" to register.', file=sys.stderr)
+        sys.exit(1)
+    return open(TOKEN_FILE).read().strip()
+
+
+def read_last_ip() -> str:
+    try:
+        return open(IP_CACHE_FILE).read().strip()
+    except FileNotFoundError:
+        return ''
+
+
+def write_last_ip(ip: str) -> None:
+    with open(IP_CACHE_FILE, 'w') as f:
+        f.write(ip)
+
+
+def main() -> int:
+    try:
+        public_ip = get_public_ip()
+    except Exception as e:
+        print(f'ERROR: Could not detect public IP: {e}', file=sys.stderr)
+        return 1
+
+    last_ip = read_last_ip()
+    if public_ip == last_ip:
+        print(f'DDNS: IP unchanged ({public_ip}) — no update needed')
+        return 0
+
+    token = read_token()
+    data = json.dumps({'token': token, 'ip': public_ip}).encode()
+    req = urllib.request.Request(
+        f'{DDNS_URL}/update',
+        data=data,
+        headers={'Content-Type': 'application/json'},
+        method='PUT',
+    )
+    try:
+        resp = urllib.request.urlopen(req, timeout=10)
+        result = json.loads(resp.read())
+        if result.get('updated'):
+            write_last_ip(public_ip)
+            print(f'DDNS: Updated to {public_ip}')
+            return 0
+        else:
+            print(f'ERROR: Unexpected response: {result}', file=sys.stderr)
+            return 1
+    except urllib.error.HTTPError as e:
+        body = e.read().decode()
+        print(f'ERROR: DDNS update failed ({e.code}): {body}', file=sys.stderr)
+        return 1
+    except Exception as e:
+        print(f'ERROR: DDNS update failed: {e}', file=sys.stderr)
+        return 1
+
+
+if __name__ == '__main__':
+    sys.exit(main())