Initial Version PoC

.gitignore

@@ -0,0 +1,49 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# Virtual environments
+venv/
+ENV/
+env/
+.venv
+
+# Environment variables
+.env
+.env.local
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# Output files
+output/
+*.png
+
+# Docker
+docker-compose.override.yml
+
+# OS
+.DS_Store
+Thumbs.db

Dockerfile

@@ -0,0 +1,24 @@
+FROM python:3.9-slim
+
+# Disable Python output buffering
+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
+WORKDIR /app
+
+# Copy requirements and install Python dependencies
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy the application
+COPY client.py .
+COPY templates.py .
+
+# Run the application
+CMD ["python", "client.py"]

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()

docker-compose.yml

@@ -0,0 +1,12 @@
+version: '3.8'
+
+services:
+  vet-label-client:
+    build: .
+    env_file:
+      - .env
+    devices:
+      - /dev/usb/lp0:/dev/usb/lp0
+    volumes:
+      - ./output:/app/output  # For test PNGs
+    restart: unless-stopped

requirements.txt

@@ -0,0 +1,3 @@
+paho-mqtt
+Pillow
+brother-ql

templates.py

@@ -0,0 +1,76 @@
+# Template definitions for different label layouts
+
+from PIL import Image, ImageDraw, ImageFont
+from datetime import date
+
+def vet_label_template(variables, width_pixels=991, height_pixels=306, filename=None):
+    """Default vet label template"""
+    image = Image.new('RGB', (width_pixels, height_pixels), 'white')
+    draw = ImageDraw.Draw(image)
+
+    try:
+        font_bold = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans-Bold.ttf', 36)
+        font_normal = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf', 32)
+        font_small = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf', 28)
+        font_footer = ImageFont.truetype('/usr/share/fonts/truetype/dejavu/DejaVuSans-Oblique.ttf', 22)
+    except:
+        font_bold = ImageFont.load_default()
+        font_normal = ImageFont.load_default()
+        font_small = ImageFont.load_default()
+        font_footer = ImageFont.load_default()
+
+    margin = 10
+    top = margin
+    left_col = margin
+    x1 = 200
+    x2 = 500
+    x3 = 750
+    line_height = 50
+
+    # Practice name (top left)
+    draw.text((left_col, top), variables.get('practice_name', ''), fill='black', font=font_bold)
+
+    # Date (top right)
+    today = date.today().strftime("%d %b %Y")
+    bbox = draw.textbbox((0, 0), today, font=font_small)
+    date_width = bbox[2] - bbox[0]
+    draw.text((width_pixels - margin - date_width, top), today, fill='black', font=font_small)
+
+    # Three columns of data
+    y = top + line_height + 10
+
+    # Column 1
+    draw.text((left_col, y), "Animal:", fill='black', font=font_normal)
+    draw.text((left_col, y + line_height), "Drug:", fill='black', font=font_normal)
+    draw.text((left_col, y + 2 * line_height), "Dose:", fill='black', font=font_normal)
+
+    # Column 2
+    draw.text((x1, y), variables.get('animal_name', ''), fill='black', font=font_normal)
+    draw.text((x1, y + line_height), variables.get('drug_name', ''), fill='black', font=font_normal)
+    draw.text((x1, y + 2 * line_height), variables.get('dosage', ''), fill='black', font=font_normal)
+
+    # Column 3
+    draw.text((x2, y), "Qty:", fill='black', font=font_normal)
+    draw.text((x2, y + line_height), "Vet:", fill='black', font=font_normal)
+
+    draw.text((x3, y), variables.get('quantity', ''), fill='black', font=font_normal)
+    draw.text((x3, y + line_height), variables.get('vet_initials', ''), fill='black', font=font_normal)
+
+    # Footer at bottom
+    footer_text = "For animal treatment only"
+    bbox = draw.textbbox((0, 0), footer_text, font=font_footer)
+    text_width = bbox[2] - bbox[0]
+    footer_x = (width_pixels - text_width) / 2
+    footer_y = height_pixels - margin - 20
+    draw.text((footer_x, footer_y), footer_text, fill='black', font=font_footer)
+
+    if filename:
+        image.save(filename)
+
+    return image
+
+# Template registry
+TEMPLATES = {
+    'vet_label': vet_label_template,
+    # Add more templates here, e.g., 'vet_label_small': vet_label_small_template
+}