"Refactor printer templates and monitor logic"

backend/app/utils/printer_monitor.py

@@ -228,10 +228,21 @@ class PrinterMonitor:
             db_session = get_db_session()
             printers = db_session.query(Printer).filter(Printer.active == True).all()
             
+            # Wenn keine aktiven Drucker vorhanden sind, gebe leeres Dict zurück
+            if not printers:
+                monitor_logger.info("ℹ️ Keine aktiven Drucker gefunden")
+                db_session.close()
+                return status_dict
+            
+            monitor_logger.info(f"🔍 Prüfe Status von {len(printers)} aktiven Druckern...")
+            
             # Parallel-Status-Prüfung mit ThreadPoolExecutor
             from concurrent.futures import ThreadPoolExecutor, as_completed
             
-            with ThreadPoolExecutor(max_workers=min(len(printers), 8)) as executor:
+            # Sicherstellen, dass max_workers mindestens 1 ist
+            max_workers = min(max(len(printers), 1), 8)
+            
+            with ThreadPoolExecutor(max_workers=max_workers) as executor:
                 future_to_printer = {
                     executor.submit(self._check_single_printer_status, printer): printer
                     for printer in printers
@@ -265,6 +276,8 @@ class PrinterMonitor:
             db_session.commit()
             db_session.close()
             
+            monitor_logger.info(f"✅ Status-Update abgeschlossen für {len(status_dict)} Drucker")
+            
         except Exception as e:
             monitor_logger.error(f"❌ Kritischer Fehler beim Abrufen des Live-Status: {str(e)}")