Demo Starting Our Frontend Interface

cd final_project/
cd ToyShop

Flask==2.2.3
python-dotenv==1.0.0
Werkzeug==2.2.3
confluent-kafka

pip3 install -r requirements.txt

# app.py
from flask import Flask, render_template, request, redirect, url_for
from confluent_kafka import Producer
import json
import logging
import socket

app = Flask(__name__)

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Kafka producer configuration
# NOTE: replace the IP below with your EC2 instance's public IP and port 9092.
conf = {
    'bootstrap.servers': '54.226.13.161:9092',
    'client.id': socket.gethostname()
}

# Initialize producer instance
producer = Producer(conf)

# Delivery callback for produced messages
def delivery_callback(err, msg):
    if err:
        logger.error(f"Message delivery failed: {err}")
    else:
        logger.info(f"Message delivered to {msg.topic()} [{msg.partition()}] at offset {msg.offset()}")
        logger.info(f"Message timestamp: {msg.timestamp()}")

# Sample product data shown on the UI
products = [
    {"id": 1, "name": "Toy 1", "price": 10.99, "image": "toy1.jpg"},
    {"id": 2, "name": "Toy 2", "price": 15.99, "image": "toy2.jpg"},
    {"id": 3, "name": "Toy 3", "price": 25.99, "image": "toy3.jpg"},
    {"id": 4, "name": "Toy 4", "price": 29.99, "image": "toy4.jpg"},
    {"id": 5, "name": "Toy 5", "price": 35.99, "image": "toy5.jpg"},
    {"id": 6, "name": "Toy 6", "price": 45.99, "image": "toy6.jpg"}
]

# Simple in-memory cart (for demo purposes)
cart = []

@app.route('/')
def index():
    return render_template('index.html', products=products, cart=cart)

@app.route('/add_to_cart', methods=['POST'])
def add_to_cart():
    product_id = int(request.form.get('product_id'))
    for p in products:
        if p['id'] == product_id:
            cart.append(p.copy())
            break
    return redirect(url_for('index'))

@app.route('/view_cart')
def view_cart():
    return render_template('cart.html', cart=cart)

@app.route('/place_order', methods=['POST'])
def place_order():
    try:
        name = request.form.get('name')
        address = request.form.get('address')

        # Prepare the order event payload
        order_event = {
            "customer_name": name,
            "delivery_address": address,
            "products": cart,
            "total_amount": sum(item["price"] for item in cart)
        }

        # Convert event to JSON string and produce to Kafka
        event_string = json.dumps(order_event)
        logger.info(f"Sending order event to Kafka: {event_string}")

        producer.produce(
            topic='cartevent',
            value=event_string.encode('utf-8'),
            callback=delivery_callback
        )

        # Ensure all messages are delivered before proceeding
        producer.flush()

        # Clear cart after successful placement
        cart.clear()

        return render_template('order.html', name=name)
    except Exception as e:
        logger.error(f"Failed to process order: {e}")
        return render_template('error.html', error=str(e))

if __name__ == '__main__':
    app.run(debug=True)

python3 app.py

INFO:werkzeug:127.0.0.1 - - [03/May/2025 10:08:31] "GET / HTTP/1.1" 200 --
INFO:werkzeug:127.0.0.1 - - [03/May/2025 10:09:26] "POST /place_order HTTP/1.1" 200 --
INFO:root:Sending order event to Kafka: {"customer_name": "Raghu", "delivery_address": "Delhi", "products": [...], "total_amount": 26.98}
INFO:root:Message delivered to cartevent [0] at offset 12

# Create topic (run on the Kafka server)
bin/kafka-topics.sh --create --topic cartevent --bootstrap-server 54.226.13.161:9092 --partitions 3 --replication-factor 1

# Consume messages from the beginning
bin/kafka-console-consumer.sh --bootstrap-server 54.226.13.161:9092 --topic cartevent --from-beginning

{"customer_name": "Raghu", "delivery_address": "Delhi", "products":[{"id": 1, "name": "Toy 1", "price": 10.99, "image": "toy1.jpg"}, {"id": 2, "name": "Toy 2", "price": 15.99, "image": "toy2.jpg"}], "total_amount": 26.98}
{"customer_name": "Bob", "delivery_address": "Paris", "products": [{"id": 6, "name": "Toy 6", "price": 35.99, "image": "toy6.jpg"}], "total_amount": 35.99}