Priority queues in RabbitMQ - Mini Project: Build & Apply

Using Priority Queues in RabbitMQ

📖 Scenario: You are managing a messaging system where some messages are more important than others. You want to make sure that high priority messages get processed first.RabbitMQ supports priority queues to handle this need.

🎯 Goal: Set up a RabbitMQ priority queue, publish messages with different priorities, and consume them to see that higher priority messages are received first.

📋 What You'll Learn

Create a priority queue named task_queue with a max priority of 10

Publish three messages with priorities 5, 10, and 1 respectively

Consume messages from the queue and print their body and priority

Verify that messages are received in order of priority (highest first)

💡 Why This Matters

🌍 Real World

Priority queues are used in real systems to ensure urgent tasks are handled before less important ones, such as in customer support ticketing or order processing.

💼 Career

Understanding how to configure and use priority queues in RabbitMQ is valuable for DevOps engineers managing messaging systems and ensuring efficient task processing.

1

Create a priority queue named task_queue

Write a RabbitMQ queue declaration command to create a queue named task_queue with the argument {'x-max-priority': 10} to enable priority support.

RabbitMQ

# Declare a priority queue named 'task_queue' with max priority 10
# Your code here

Need a hint?

Use queue_declare with the arguments parameter to set x-max-priority.

2

Publish three messages with priorities 5, 10, and 1

Write three basic_publish commands to send messages with bodies 'Message 1', 'Message 2', and 'Message 3' to the task_queue. Set the priority property to 5, 10, and 1 respectively.

RabbitMQ

channel.queue_declare(queue='task_queue', arguments={'x-max-priority': 10})
# Publish 'Message 1' with priority 5
# Publish 'Message 2' with priority 10
# Publish 'Message 3' with priority 1
# Your code here

Need a hint?

Use basic_publish with properties=pika.BasicProperties(priority=...) to set message priority.

3

Consume messages and print their body and priority

Write a consumer callback function named callback that takes ch, method, properties, body and prints the message body and its priority from properties.priority. Then start consuming from task_queue using channel.basic_consume with callback and auto_ack=True.

RabbitMQ

channel.queue_declare(queue='task_queue', arguments={'x-max-priority': 10})
channel.basic_publish(exchange='', routing_key='task_queue', body='Message 1', properties=pika.BasicProperties(priority=5))
channel.basic_publish(exchange='', routing_key='task_queue', body='Message 2', properties=pika.BasicProperties(priority=10))
channel.basic_publish(exchange='', routing_key='task_queue', body='Message 3', properties=pika.BasicProperties(priority=1))

# Define callback to print body and priority
# Start consuming from 'task_queue'
# Your code here

Need a hint?

Define a callback function that prints the message and priority, then use basic_consume to start consuming.

4

Start consuming and observe message order

Write the command to start consuming messages from RabbitMQ using channel.start_consuming(). This will print messages in order of priority.

RabbitMQ

def callback(ch, method, properties, body):
    print(f"Received: {body.decode()} with priority {properties.priority}")

channel.queue_declare(queue='task_queue', arguments={'x-max-priority': 10})
channel.basic_publish(exchange='', routing_key='task_queue', body='Message 1', properties=pika.BasicProperties(priority=5))
channel.basic_publish(exchange='', routing_key='task_queue', body='Message 2', properties=pika.BasicProperties(priority=10))
channel.basic_publish(exchange='', routing_key='task_queue', body='Message 3', properties=pika.BasicProperties(priority=1))

channel.basic_consume(queue='task_queue', on_message_callback=callback, auto_ack=True)

# Start consuming messages
# Your code here

Need a hint?

Use channel.start_consuming() to begin receiving messages.