by Example

A queue push consumer is analogous to a core NATS queue group, but designed to work with streams. Unlike a standard push consumer which only supports a single bound subscription at any time, a queue-based one supports multiple subscriptions bound to the consumer. Messages from the consumer will be distributed randomly among active subscribers which can freely come and go.

In this example, we will demonstrate how to create a durable queue push consumer and how to bind subscriptions to receive and process messages.

Note that as of NATS server v2.8.4, ephemeral queue push consumers are not supported. This means that the server does not currently keep track of these and will auto-cleanup if no active subscriptions are bound. You can, of course, create a durable and then delete once you are done with it, but if the deletion fails to happen (program crashes), you will need to be sure to check when the starts up again.

It is recommended to review the standard push consumer example in order to understand the general concepts. The queue-based variant is a small extension to this type of consumer.