RabbitMQ and message priority

Question

Does RabbitMQ have any concept of message priority? I have an issue were some more important messages are being slowed down due to less important messages sitting before it

Answer 1

Yes, RabbitMQ supports priority queues.

To make a queue work as a priority queue, supply property x-max-priority when declaring the queue.

Property x-max-priority defines the maximum priority number the queue supports.

In Java, you can do like below:

Map props = new HashMap<>();
props.put("x-max-priority", 10); // max priority number as 10
channel.queueDeclare(QUEUE_NAME, durable, false, false, props);

To publish messages of a particular priority, do like below:

String message = "My message with priority 7";
AMQP.BasicProperties.Builder basicProps = new AMQP.BasicProperties.Builder();
basicProps.contentType("text/plain")
            .priority(7);
channel.basicPublish("", QUEUE_NAME, basicProps.build(), message.getBytes());