The provided text appears to be a log of changes made in a software project, likely using version control systems like Git. Here's a breakdown:

backend/utils/database_cleanup.py

@@ -0,0 +1,84 @@
+"""
+Database Cleanup Manager für sicheres Database-Management.
+Zentrale Verwaltung von Database-Connections und Cleanup-Operationen.
+"""
+
+import logging
+from typing import Optional, List
+from contextlib import contextmanager
+import threading
+import weakref
+
+from utils.logging_config import get_logger
+
+logger = get_logger(__name__)
+
+
+class DatabaseCleanupManager:
+    """
+    Manager für sichere Database-Cleanup-Operationen.
+    Verwaltet Database-Engines und sorgt für sauberes Shutdown.
+    """
+    
+    def __init__(self):
+        self._engines = weakref.WeakSet()
+        self._lock = threading.Lock()
+        logger.debug("DatabaseCleanupManager initialisiert")
+    
+    def register_engine(self, engine):
+        """
+        Registriert eine Database-Engine für Cleanup beim Shutdown.
+        
+        Args:
+            engine: SQLAlchemy Engine-Objekt
+        """
+        with self._lock:
+            self._engines.add(engine)
+            logger.debug(f"Database-Engine registriert: {engine}")
+    
+    def cleanup_all(self):
+        """
+        Führt Cleanup für alle registrierten Engines durch.
+        """
+        with self._lock:
+            for engine in list(self._engines):
+                try:
+                    if hasattr(engine, 'dispose'):
+                        engine.dispose()
+                        logger.debug(f"Engine disposed: {engine}")
+                except Exception as e:
+                    logger.error(f"Fehler beim Engine-Cleanup: {e}")
+            
+            # Set leeren
+            self._engines.clear()
+            logger.info("Database-Cleanup abgeschlossen")
+    
+    def get_engine_count(self) -> int:
+        """
+        Gibt die Anzahl der registrierten Engines zurück.
+        """
+        with self._lock:
+            return len(self._engines)
+
+
+# Globaler Cleanup-Manager
+_cleanup_manager = None
+_manager_lock = threading.Lock()
+
+
+def get_cleanup_manager() -> DatabaseCleanupManager:
+    """
+    Gibt den globalen DatabaseCleanupManager zurück (Singleton).
+    
+    Returns:
+        DatabaseCleanupManager: Der globale Cleanup-Manager
+    """
+    global _cleanup_manager
+    
+    if _cleanup_manager is None:
+        with _manager_lock:
+            if _cleanup_manager is None:
+                _cleanup_manager = DatabaseCleanupManager()
+                logger.debug("Globaler DatabaseCleanupManager erstellt")
+    
+    return _cleanup_manager