Message Queues: RabbitMQ vs Kafka — Which to Choose

Message Queues: RabbitMQ vs Kafka

Message queues decouple services and enable async processing. Choosing between them is a common system design question.

import pika, json

# RabbitMQ — Publisher
conn    = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = conn.channel()
channel.exchange_declare(exchange='app', exchange_type='topic')
channel.queue_declare(queue='email_queue', durable=True)
channel.queue_bind(exchange='app', queue='email_queue', routing_key='user.*')

channel.basic_publish(
    exchange='app', routing_key='user.registered',
    body=json.dumps({'user_id': 42, 'email': 'r@e.com'}),
    properties=pika.BasicProperties(delivery_mode=2)  # persistent
)

# Consumer
def callback(ch, method, props, body):
    data = json.loads(body)
    send_welcome_email(data['email'])
    ch.basic_ack(delivery_tag=method.delivery_tag)

# Kafka — Producer and Consumer
from kafka import KafkaProducer, KafkaConsumer

producer = KafkaProducer(bootstrap_servers='localhost:9092',
                         value_serializer=lambda v: json.dumps(v).encode())
producer.send('user-events', {'event': 'registered', 'user_id': 42})

consumer = KafkaConsumer('user-events', bootstrap_servers='localhost:9092',
                         group_id='email-service')
for message in consumer:
    process_event(json.loads(message.value))