RabbitMQ Priority Queues (Message Priority)

Priority queues, as the name suggests, give priority to messages with higher priority to be consumed.

Points to note for RabbitMQ priority queues:

• Priority queues only take effect when there are insufficient consumers and consumption cannot be done in a timely manner.
• Priority queues are supported only after RabbitMQ version 3.5.

Steps to Use RabbitMQ Priority Queues

1. Set the maximum priority of the queue.
2. Set the priority of the message.

Set the Maximum Priority of the Queue

When declaring the queue, set the maximum priority of the queue through the queue property (x-max-priority). The maximum value for priority is 255, and it is recommended to set it between 1 and 10. Setting in Golang:

	// Queue properties
	props := make(map[string]interface{})
	// Set the maximum priority of the queue
	props["x-max-priority"] = 10

// Declare the queue
q, err := ch.QueueDeclare(
	"tizi365.hello", // Queue name
	true,  // Queue durable
	false, // Delete when unused
	false, // Exclusive
	false, // No-wait
	props, // Set queue properties
)

Tip: The setting method in other languages is similar.

Set the Message Priority

Setting in Golang:

err = ch.Publish(
	"tizi365",     // Exchange
	"", // Routing key
	false,
	false,
	amqp.Publishing{
		Priority:5, // Set the message priority
		DeliveryMode:2,  // Message delivery mode, 1 for non-persistent, 2 for persistent
		ContentType: "text/plain",
		Body:        []byte(body),
	})