Robustness fixes

Dockerfile

@@ -6,7 +6,6 @@ ENV PYTHONUNBUFFERED=1
 # Install system dependencies
 RUN apt-get update && apt-get install -y \
     fonts-dejavu \
-    usbutils \
     && rm -rf /var/lib/apt/lists/*
 
 # Set working directory
@@ -16,9 +15,6 @@ WORKDIR /app
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
 
-# Copy the application
-COPY client.py .
-COPY templates.py .
-
+# Application files will be mounted via volume
 # Run the application
 CMD ["python", "client.py"]

client.py

@@ -22,15 +22,22 @@ LABEL_SIZE_DEFAULT = os.getenv('LABEL_SIZE_DEFAULT', '29x90')
 
 def print_label(image, printer=PRINTER_DEVICE, model=PRINTER_MODEL, label=LABEL_SIZE_DEFAULT):
     """Print the label directly using brother_ql module"""
+    import os
+    
     try:
+        # Check if printer device exists
+        if not os.path.exists(printer):
+            raise Exception(f"Printer device {printer} not found. Make sure the printer is powered on and connected via USB.")
+        
         qlr = BrotherQLRaster(model)
         qlr.exception_on_warning = True
         
         # Convert the PIL image to instructions
         instructions = convert(qlr=qlr, images=[image], label=label, cut=True)
         
-        # Send to printer
-        status = send(instructions=instructions, printer_identifier=printer, backend_identifier='linux_kernel', blocking=True)
+        # Send to printer using linux_kernel backend
+        print(f"Sending to printer: {printer}")
+        status = send(instructions=instructions, printer_identifier=f"file://{printer}", backend_identifier='linux_kernel', blocking=True)
         
         return status
     except Exception as e:
@@ -83,6 +90,29 @@ def on_message(client, userdata, msg):
             status = print_label(image, label=label_size)
             print(f"Print status: {status}")
             
+            # Check for print errors
+            if not status.get('did_print', False):
+                printer_state = status.get('printer_state', {})
+                status_type = printer_state.get('status_type', 'Unknown')
+                media_type = printer_state.get('media_type', 'Unknown')
+                media_width = printer_state.get('media_width', 'Unknown')
+                errors = printer_state.get('errors', [])
+                
+                error_details = {
+                    "error": f"Print failed: {status_type}",
+                    "status_type": status_type,
+                    "media_type": media_type,
+                    "media_width": media_width,
+                    "errors": errors,
+                    "outcome": status.get('outcome', 'unknown'),
+                    "original_payload": raw_payload
+                }
+                
+                error_msg = f"Print failed: {status_type}. Media: {media_type} ({media_width}mm)"
+                print(error_msg)
+                client.publish(MQTT_TOPIC_PUB_ERRORS, json.dumps(error_details))
+                raise Exception(error_msg)
+
     except json.JSONDecodeError as e:
         error_msg = f"Invalid JSON in message: {e}. Raw payload: {raw_payload}"
         print(error_msg)

docker-compose.yml

@@ -5,8 +5,10 @@ services:
     build: .
     env_file:
       - .env
-    devices:
-      - /dev/usb/lp0:/dev/usb/lp0
+    privileged: true  # Required for /dev access when printer powers on/off
     volumes:
       - ./output:/app/output  # For test PNGs
+      - ./client.py:/app/client.py  # Mount source for live updates
+      - ./templates.py:/app/templates.py  # Mount templates for live updates
+      - /dev:/dev  # Mount /dev for dynamic device access
     restart: unless-stopped