Change the way a Printer is used by the worker

src/printers.py

@@ -6,6 +6,7 @@ the methods expected from printers.
 """
 
 from collections.abc import Set
+import time
 import usb.core
 import usb.util
 from printer import Printer, EscPosPrinter, BrotherPrinter
@@ -41,7 +42,17 @@ class Printers:
 
         # Find all connected USB devices
         devices = usb.core.find(find_all=True, custom_match=_FindClass(7))
-        if not devices:
+        waiting_time_for_printer = 10
+        while not list(devices):
+            self.app.logger.warning(str(waiting_time_for_printer) + " Found no printers, waiting for a printer to connect to the system...")
+            time.sleep(1)
+            waiting_time_for_printer = waiting_time_for_printer - 1
+            devices = usb.core.find(find_all=True, custom_match=_FindClass(7))
+            if waiting_time_for_printer == 0:
+                break
+
+
+        if not list(devices):
             self.app.logger.warning(
                 "No USB devices of class 7 ( printers ) found or pyusb could not access the bus."
             )
@@ -60,6 +71,7 @@ class Printers:
                 product = usb.util.get_string(dev, dev.iProduct)
             except Exception:
                 product = "Unknown"
+
             self.app.logger.debug(
                 "Looking at %s %s (%s:%s)",
                 manufacturer,