Initial Version PoC

client.py

@@ -0,0 +1,137 @@
+import os
+import json
+import time
+import threading
+import paho.mqtt.client as mqtt
+from PIL import Image, ImageDraw, ImageFont
+from datetime import date
+from brother_ql.raster import BrotherQLRaster
+from brother_ql.conversion import convert
+from brother_ql.backends.helpers import send
+from templates import TEMPLATES
+
+# Load configuration from environment
+MQTT_HOST = os.getenv('MQTT_HOST', 'localhost')
+MQTT_PORT = int(os.getenv('MQTT_PORT', 1883))
+MQTT_TOPIC_SUB = os.getenv('MQTT_TOPIC_SUB', 'vet/labels/print')
+MQTT_TOPIC_PUB_ERRORS = os.getenv('MQTT_TOPIC_PUB_ERRORS', 'vet/labels/errors')
+MQTT_TOPIC_HEARTBEAT = os.getenv('MQTT_TOPIC_HEARTBEAT', 'vet/labels/heartbeat')
+PRINTER_DEVICE = os.getenv('PRINTER_DEVICE', '/dev/usb/lp0')
+PRINTER_MODEL = os.getenv('PRINTER_MODEL', 'QL-800')
+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"""
+    try:
+        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)
+        
+        return status
+    except Exception as e:
+        raise e
+
+def on_connect(client, userdata, flags, rc):
+    print(f"Connected to MQTT broker at {MQTT_HOST}:{MQTT_PORT} with result code {rc}")
+    if rc == 0:
+        print(f"Subscribing to topic: {MQTT_TOPIC_SUB}")
+        client.subscribe(MQTT_TOPIC_SUB)
+        print("Subscription successful")
+    else:
+        print(f"Failed to connect, result code: {rc}")
+
+def on_message(client, userdata, msg):
+    try:
+        raw_payload = msg.payload.decode('utf-8')
+    except UnicodeDecodeError:
+        print(f"Received non-UTF-8 message on topic '{msg.topic}': {msg.payload}")
+        return
+
+    print(f"Raw message received on topic '{msg.topic}': {raw_payload}")
+    try:
+        payload = json.loads(raw_payload)
+        print(f"Parsed payload: {payload}")
+
+        template_id = payload.get('template_id', 'vet_label')
+        label_size = payload.get('label_size', LABEL_SIZE_DEFAULT)
+        variables = payload.get('variables', {})
+        test = payload.get('test', False)
+
+        print(f"Processing: template_id={template_id}, label_size={label_size}, test={test}")
+
+        # For now, only support one template
+        if template_id not in TEMPLATES:
+            raise ValueError(f"Unknown template_id: {template_id}")
+
+        template_func = TEMPLATES[template_id]
+
+        # TODO: Adjust dimensions based on label_size if needed
+        # For simplicity, using fixed dimensions
+
+        filename = f"/app/output/label_{template_id}.png" if test else None
+        image = template_func(variables, filename=filename)
+
+        if test:
+            print(f"Test mode: PNG saved as {filename}")
+        else:
+            print("Printing label...")
+            status = print_label(image, label=label_size)
+            print(f"Print status: {status}")
+
+    except json.JSONDecodeError as e:
+        error_msg = f"Invalid JSON in message: {e}. Raw payload: {raw_payload}"
+        print(error_msg)
+        client.publish(MQTT_TOPIC_PUB_ERRORS, json.dumps({"error": error_msg, "topic": msg.topic}))
+    except Exception as e:
+        error_msg = f"Error processing message: {str(e)}"
+        print(error_msg)
+        client.publish(MQTT_TOPIC_PUB_ERRORS, json.dumps({"error": error_msg, "original_payload": raw_payload}))
+
+def heartbeat(client):
+    while True:
+        try:
+            heartbeat_msg = {
+                "status": "alive",
+                "timestamp": time.time(),
+                "host": MQTT_HOST,
+                "port": MQTT_PORT
+            }
+            client.publish(MQTT_TOPIC_HEARTBEAT, json.dumps(heartbeat_msg))
+            print(f"Published heartbeat: {heartbeat_msg}")
+            time.sleep(30)  # Publish every 30 seconds
+        except Exception as e:
+            print(f"Error publishing heartbeat: {e}")
+            time.sleep(5)  # Retry sooner on error
+
+def main():
+    client = mqtt.Client()
+    client.on_connect = on_connect
+    client.on_message = on_message
+
+    print(f"Attempting to connect to MQTT broker at {MQTT_HOST}:{MQTT_PORT}")
+    client.connect(MQTT_HOST, MQTT_PORT, 60)
+
+    # Start the network loop in a background thread
+    client.loop_start()
+
+    # Start heartbeat thread
+    heartbeat_thread = threading.Thread(target=heartbeat, args=(client,))
+    heartbeat_thread.daemon = True
+    heartbeat_thread.start()
+
+    print("Client is running. Press Ctrl+C to stop.")
+    try:
+        while True:
+            time.sleep(1)  # Keep main thread alive
+    except KeyboardInterrupt:
+        print("Shutting down...")
+        client.loop_stop()
+        client.disconnect()
+
+if __name__ == "__main__":
+    main()