b

app.py

@@ -34,6 +34,9 @@ printer_model = "QL-1100"
 backend = 'pyusb'
 printer = 'usb://0x04f9:0x20a7'
 
+# Create a lock to manage printer access
+printer_lock = threading.Lock()
+
 # Convert PDF to image
 def convert_pdf_to_image(pdf_path):
     """Converts a PDF to a PIL Image"""
@@ -47,6 +50,19 @@ def convert_pdf_to_image(pdf_path):
         app.logger.error(f"Error converting PDF: {str(e)}")
         return None
 
+# Reinitialize the printer by disconnecting and reconnecting
+def reinitialize_printer():
+    try:
+        app.logger.info("Reinitializing printer...")
+        usb_device = usb.core.find(idVendor=0x04f9, idProduct=0x20a7)
+        if usb_device:
+            usb_device.reset()
+            app.logger.info("Printer reinitialized successfully.")
+        else:
+            app.logger.error("Failed to find printer device.")
+    except Exception as e:
+        app.logger.error(f"Error reinitializing printer: {str(e)}")
+
 # Function to print address labels
 def print_address_label(pdf_path):
     try:
@@ -77,17 +93,40 @@ def print_address_label(pdf_path):
             cut=True
         )
 
-        app.logger.info("Sending to printer...")
+        # Try to acquire the printer lock with a longer timeout
-        send(
+        max_retries = 5  # Retry up to 5 times
-            instructions=instructions, 
+        retry_delay = 5  # Retry every 5 seconds
-            printer_identifier=printer, 
+        for attempt in range(max_retries):
-            backend_identifier=backend, 
+            if printer_lock.acquire(timeout=30):  # 30 seconds timeout to allow more time for the printer
-            blocking=True
+                try:
-        )
+                    app.logger.info(f"Attempting to send print job (Attempt {attempt + 1})...")
-        app.logger.info("Print job sent successfully")
+                    send(
-        
+                        instructions=instructions, 
+                        printer_identifier=printer, 
+                        backend_identifier=backend, 
+                        blocking=True  # Ensure blocking, so we wait for the print to complete
+                    )
+                    app.logger.info("Print job sent successfully")
+                    break
+                except Exception as e:
+                    app.logger.error(f"Error during printing: {str(e)}")
+                    if attempt < max_retries - 1:
+                        app.logger.info(f"Retrying after {retry_delay} seconds...")
+                        time.sleep(retry_delay)
+                    else:
+                        app.logger.error("Max retries reached. Failed to send print job.")
+                        reinitialize_printer()  # Reinitialize printer after retries
+            else:
+                app.logger.error(f"Failed to acquire printer lock (Attempt {attempt + 1}). Printer is busy.")
+                if attempt < max_retries - 1:
+                    app.logger.info(f"Retrying after {retry_delay} seconds...")
+                    time.sleep(retry_delay)
+                else:
+                    app.logger.error("Printer is still busy after retries.")
+                    raise Exception("Printer is busy. Try again later.")
+    
     except Exception as e:
-        app.logger.error(f"Error during printing: {str(e)}")
+        app.logger.error(f"Error during label printing: {str(e)}")
 
 # Worker thread that processes files from the queue
 def process_queue():