How to re-perform failed tasks?

Question

RabbitMQ

There is a module that adds a store, then Rabbit queues a task to get information about this store from an external site. It may be that the external site is temporarily disabled (for an update or for some other reason), in which case the task will not be completed.
How to make sure that the task is still completed when the site is available again?

Answer 1

RabbitMQ is unlikely to know when some external site becomes available, the easiest option here is to wait and try again.
RabbitMQ can do this using the Dead Letter Exchanges extension :
* On the main queue - Q1 - the policy is hung / the dead-letter-exchange=Q2 option is set
* The policy / option dead-letter-exchange=Q1 + message-ttl= is hung on Q2 <time between repeats>