Change to peewee DatabaseProxy to handle different DB types

src/ddns_service/models.py

@@ -7,6 +7,7 @@ from . import utc_now
 from peewee import (
     AutoField,
     CharField,
+    DatabaseProxy,
     DateTimeField,
     DoesNotExist,
     fn,
@@ -17,8 +18,8 @@ from peewee import (
     SqliteDatabase,
 )
 
-# Database instance (initialized later)
-db = SqliteDatabase(None)
+# Database proxy (initialized later with actual backend)
+db = DatabaseProxy()
 
 # Current database schema version
 DATABASE_VERSION = 2
@@ -110,7 +111,6 @@ def init_database(config: dict):
     Raises:
         ValueError: If unknown database backend.
     """
-    global db
 
     backend = config["database"].get("backend", "sqlite")
 
@@ -119,21 +119,19 @@ def init_database(config: dict):
         db_dir = os.path.dirname(db_path)
         if db_dir:
             os.makedirs(db_dir, exist_ok=True)
-        db.init(db_path)
+        actual_db = SqliteDatabase(db_path)
+        db.initialize(actual_db)
         logging.debug(f"Database backend: SQLite path={db_path}")
 
     elif backend == "mariadb":
-        db = MySQLDatabase(
+        actual_db = MySQLDatabase(
             config["database"]["database"],
             host=config["database"].get("host", "localhost"),
             port=config["database"].get("port", 3306),
             user=config["database"]["user"],
             password=config["database"]["password"],
         )
-        # Re-bind models to new database
-        User._meta.database = db
-        Hostname._meta.database = db
-        Version._meta.database = db
+        db.initialize(actual_db)
         db_name = config['database']['database']
         logging.debug(f"Database backend: MariaDB db={db_name}")