Scaffold PD Pi-hole primary stack

pihole/bin/render_keepalived_conf.py

@@ -0,0 +1,67 @@
+#!/usr/bin/env python3
+from __future__ import annotations
+import os
+import re
+import sys
+from pathlib import Path
+
+STACK_DIR = Path(__file__).resolve().parent.parent
+ENV_FILE = Path(os.environ.get('ENV_FILE', STACK_DIR / '.env'))
+TEMPLATE = STACK_DIR / 'keepalived.conf.template'
+OUTPUT = STACK_DIR / 'keepalived.conf'
+
+
+def load_env(path: Path) -> dict[str, str]:
+    env = dict(os.environ)
+    if path.exists():
+        for raw in path.read_text(encoding='utf-8').splitlines():
+            line = raw.strip()
+            if not line or line.startswith('#') or '=' not in line:
+                continue
+            k, v = line.split('=', 1)
+            env.setdefault(k.strip(), v.strip().strip('"').strip("'"))
+    return env
+
+
+def main() -> int:
+    env = load_env(ENV_FILE)
+    required = [
+        'LAN_INTERFACE', 'VIP_CIDR', 'KEEPALIVED_ROUTER_ID', 'KEEPALIVED_STATE',
+        'KEEPALIVED_PRIORITY', 'KEEPALIVED_PASSWORD', 'PD_PIHOLE_WEB_PORT'
+    ]
+    missing = [k for k in required if not env.get(k)]
+    if missing:
+        print(f'Missing required vars in {ENV_FILE}: {", ".join(missing)}', file=sys.stderr)
+        return 1
+
+    keepalived_password = env['KEEPALIVED_PASSWORD']
+    if len(keepalived_password) > 8:
+        print('KEEPALIVED_PASSWORD must be 8 characters or fewer for VRRP PASS auth.', file=sys.stderr)
+        return 1
+
+    try:
+        web_port_hex = f"{int(env['PD_PIHOLE_WEB_PORT']):04X}"
+    except ValueError:
+        print('PD_PIHOLE_WEB_PORT must be an integer.', file=sys.stderr)
+        return 1
+
+    router_id_name = f"pihole_{re.sub(r'[^a-z0-9]+', '_', env['KEEPALIVED_STATE'].lower())}"
+    nopreempt_line = '    nopreempt' if env.get('KEEPALIVED_NOPREEMPT', 'true').lower() in {'1','true','yes','on'} else ''
+
+    rendered = TEMPLATE.read_text(encoding='utf-8')
+    replacements = {
+        'ROUTER_ID_NAME': router_id_name,
+        'PIHOLE_WEB_PORT_HEX': web_port_hex,
+        'NOPREEMPT_LINE': nopreempt_line,
+    }
+    replacements.update({k: env[k] for k in required})
+    for key, value in replacements.items():
+        rendered = rendered.replace('${' + key + '}', value)
+
+    OUTPUT.write_text(rendered.rstrip() + '\n', encoding='utf-8')
+    print(f'Rendered {OUTPUT}')
+    return 0
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())