/shutdown and spring integration orderly shutdown

[srnm]

The current implementation of the /shutdown endpoint does not delegate to SI's orderly shutdown mechanism when available.

Thanks!

[wilkinsona]

See also #4657

[xak2000]

Also I should ask, how to properly shutdown spring-integration even without /shutdown endpoint? i.e. just from plain SIGTERM. Out of the box the container shutting down asap, not allowing any in-process handlers to complete. So any beans used by processing method are already destroyed when it completes (transactions cannot commit, jpa unit already closed etc).

For now I solved this problem by declaring custom taskScheduler bean, which spring-integration is using for poller's creation.

	@Bean
	public TaskScheduler taskScheduler() {
		ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
		scheduler.setPoolSize(10);
		scheduler.setWaitForTasksToCompleteOnShutdown(true);
		scheduler.setAwaitTerminationSeconds(20);
		return scheduler;
	}

The key part is setAwaitTerminationSeconds(20). It prevents container shutting down util TaskScheduler's in-flight tasks (spring-integration's pollers in this case) finish their work.

But I wonder if this is correct approach? Maybe when Spring destroys taskScheduler bean, some beans may already be destroyed?

I was very surprised that official spring-integration documentation has no any words about graceful shutdown the message flow (with the exception of the JMX). Isn't it the first question, that each developer asks himself when trying to use spring-integration for his needs?

This question is maybe offtopic for this issue, but maybe it makes you wonder about things that may have been overlooked otherwise.

[srnm]

One way to control shutdown order is via a "depends-on" declaration when defining the bean.

Another way may be to use parent/child ApplicationContexts.
However, setting up parent/child contexts appears to be a little complicated in Spring Boot.
It seems only to be used for servlet contexts...

More docs/guidance here would be appreciated.