From 257db866f00c72ad7f5be58edf80f49a0e42d023 Mon Sep 17 00:00:00 2001
From: Slawek Koszewski <slawek@koszewscy.waw.pl>
Date: Mon, 23 Jun 2025 00:00:53 +0200
Subject: [PATCH] Added Python version of the program.

---
 netbox-dns-updater.py | 138 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100755 netbox-dns-updater.py

diff --git a/netbox-dns-updater.py b/netbox-dns-updater.py
new file mode 100755
index 0000000..b52ae9f
--- /dev/null
+++ b/netbox-dns-updater.py
@@ -0,0 +1,138 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+netbox-dns-updater.py
+A script to update DNSMasq configuration with IP addresses from NetBox.
+It fetches IP addresses from the NetBox API and writes them to a dnsmasq configuration file.
+It also provides a simple HTTP server to trigger updates via a web request.
+"""
+
+import os
+import sys
+import argparse
+import json
+from urllib.parse import urljoin
+from urllib.request import Request, urlopen
+import logging
+import subprocess
+from http.server import BaseHTTPRequestHandler, HTTPServer
+import threading
+
+logging.basicConfig(level=logging.INFO)
+
+def get_netbox_token():
+    token = os.environ.get("NETBOX_TOKEN")
+    if token:
+        return token.strip()
+    home = os.environ.get("HOME", "")
+    paths = [
+        os.path.join(home, ".netbox", "token"),
+        "/etc/netbox/token",
+    ]
+    for path in paths:
+        try:
+            with open(path) as f:
+                return f.read().strip()
+        except Exception:
+            continue
+    logging.error("NETBOX_TOKEN not set and no token file found")
+    sys.exit(1)
+
+def fetch_netbox_ipaddresses(api_base_url, token):
+    url = urljoin(api_base_url.rstrip('/') + '/', "ipam/ip-addresses/")
+    headers = {
+        "Accept": "application/json",
+        "Authorization": f"Token {token}",
+    }
+    req = Request(url, headers=headers)
+    try:
+        with urlopen(req) as resp:
+            if resp.status != 200:
+                body = resp.read().decode()
+                logging.error(f"Unexpected status: {resp.status}, body: {body}")
+                sys.exit(1)
+            data = json.load(resp)
+    except Exception as e:
+        logging.error(f"HTTP error: {e}")
+        sys.exit(1)
+    results = []
+    for entry in data.get("results", []):
+        dns_name = entry.get("dns_name", "")
+        address = entry.get("address", "")
+        if dns_name and address:
+            address = address.split("/")[0]
+            results.append((dns_name, address))
+    return results
+
+def create_dnsmasq_config(api_base_url, write_config=True):
+    token = get_netbox_token()
+    ips = fetch_netbox_ipaddresses(api_base_url, token)
+    dir_path = "/etc/dnsmasq.d"
+    lines = [f"address=/{dns}/{ip}\n" for dns, ip in ips]
+    if os.path.isdir(dir_path) and write_config:
+        try:
+            with open(os.path.join(dir_path, "netbox.conf"), "w") as f:
+                f.writelines(lines)
+            logging.info("Wrote netbox.conf to /etc/dnsmasq.d/")
+        except Exception as e:
+            logging.error(f"Failed to write netbox.conf: {e}")
+            sys.exit(1)
+    else:
+        sys.stdout.writelines(lines)
+
+def restart_dnsmasq():
+    try:
+        subprocess.run(["systemctl", "restart", "dnsmasq.service"], check=True)
+        logging.info("dnsmasq.service restarted.")
+    except Exception as e:
+        logging.warning(f"Failed to restart dnsmasq.service: {e}")
+
+class DnsmasqHandler(BaseHTTPRequestHandler):
+    api_base_url = None
+
+    def do_GET(self):
+        if self.path == "/update-dnsmasq":
+            create_dnsmasq_config(self.api_base_url, write_config=True)
+            restart_dnsmasq()
+            self.send_response(200)
+            self.send_header('Content-type', 'text/plain')
+            self.end_headers()
+            self.wfile.write(b"DNSMasq config updated.")
+        else:
+            self.send_response(404)
+            self.end_headers()
+            self.wfile.write(b"Not found.")
+
+def run_server(listen_addr, api_base_url):
+    if ':' in listen_addr:
+        host, port = listen_addr.split(":", 1)
+        port = int(port)
+    else:
+        host, port = "0.0.0.0", int(listen_addr)
+    DnsmasqHandler.api_base_url = api_base_url
+    server = HTTPServer((host, port), DnsmasqHandler)
+    logging.info(f"Starting web service on {host}:{port} ...")
+    try:
+        server.serve_forever()
+    except KeyboardInterrupt:
+        pass
+    finally:
+        server.server_close()
+        logging.info("Server stopped.")
+
+def main():
+    parser = argparse.ArgumentParser(description="NetBox DNSMasq Updater")
+    parser.add_argument("--listen", default="0.0.0.0:8080", help="address and port to listen on (default: 0.0.0.0:8080)")
+    parser.add_argument("--api-url", default="https://netbox.koszewscy.waw.pl/api/", help="NetBox API base URL")
+    parser.add_argument("--dry-run", action="store_true", help="print output instead of writing to dnsmasq config")
+    args = parser.parse_args()
+
+    if args.dry_run:
+        logging.info("Dry run mode enabled, not writing to dnsmasq config file.")
+        create_dnsmasq_config(args.api_url, write_config=False)
+        sys.exit(0)
+
+    run_server(args.listen, args.api_url)
+
+if __name__ == "__main__":
+    main()
\ No newline at end of file