Topic exchange (pattern matching) in RabbitMQ - Mini Project: Build & Apply

Topic Exchange with Pattern Matching in RabbitMQ

📖 Scenario: You are setting up a messaging system for a news service. Different news categories like sports, weather, and finance send messages. You want to route messages to queues based on topics using pattern matching.

🎯 Goal: Build a RabbitMQ topic exchange setup where messages are routed to queues based on matching routing keys with patterns.

📋 What You'll Learn

Create a topic exchange named news_topic_exchange

Create two queues named sports_queue and weather_queue

Bind sports_queue with the routing key pattern sports.*

Bind weather_queue with the routing key pattern weather.#

Publish messages with routing keys sports.football and weather.rain

Consume and print messages from both queues

💡 Why This Matters

🌍 Real World

Topic exchanges are used in messaging systems to route messages based on flexible patterns, like categorizing news or logs.

💼 Career

Understanding topic exchanges is important for configuring message brokers in microservices, event-driven architectures, and distributed systems.

1

Create the topic exchange and queues

Create a topic exchange called news_topic_exchange. Then create two queues named sports_queue and weather_queue.

RabbitMQ

# Your code here to declare exchange and queues

Need a hint?

Use exchange_declare with exchange_type='topic' and queue_declare for queues.

2

Bind queues with routing key patterns

Bind the queue sports_queue to news_topic_exchange with the routing key pattern sports.*. Bind the queue weather_queue with the routing key pattern weather.#.

RabbitMQ

import pika

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='news_topic_exchange', exchange_type='topic')
channel.queue_declare(queue='sports_queue')
channel.queue_declare(queue='weather_queue')

# Bind sports_queue with 'sports.*'
# Bind weather_queue with 'weather.#'
# Your code here

Need a hint?

Use queue_bind with the correct routing_key patterns.

3

Publish messages with routing keys

Publish a message with the routing key sports.football and body 'Football news'. Then publish a message with the routing key weather.rain and body 'Rain forecast' to the news_topic_exchange.

RabbitMQ

import pika

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='news_topic_exchange', exchange_type='topic')
channel.queue_declare(queue='sports_queue')
channel.queue_declare(queue='weather_queue')

channel.queue_bind(exchange='news_topic_exchange', queue='sports_queue', routing_key='sports.*')
channel.queue_bind(exchange='news_topic_exchange', queue='weather_queue', routing_key='weather.#')

# Publish message with routing key 'sports.football' and body 'Football news'
# Publish message with routing key 'weather.rain' and body 'Rain forecast'
# Your code here

Need a hint?

Use basic_publish with the correct exchange, routing_key, and body.

4

Consume and print messages from queues

Consume one message from sports_queue and print its body. Then consume one message from weather_queue and print its body.

RabbitMQ

import pika

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='news_topic_exchange', exchange_type='topic')
channel.queue_declare(queue='sports_queue')
channel.queue_declare(queue='weather_queue')

channel.queue_bind(exchange='news_topic_exchange', queue='sports_queue', routing_key='sports.*')
channel.queue_bind(exchange='news_topic_exchange', queue='weather_queue', routing_key='weather.#')

channel.basic_publish(exchange='news_topic_exchange', routing_key='sports.football', body='Football news')
channel.basic_publish(exchange='news_topic_exchange', routing_key='weather.rain', body='Rain forecast')

# Consume one message from sports_queue and print its body
# Consume one message from weather_queue and print its body
# Your code here

Need a hint?

Use basic_get with auto_ack=True to get messages and print their decoded bodies.