When virtual threads are enabled, auto-configure an AsyncTaskExecutor that uses them

[wilkinsona]

Currently, TaskExecutionAutoConfiguration auto-configures a ThreadPoolTaskExecutor built using TaskExecutorBuilder. We should consider providing an option to auto-configure a SimpleAsyncTaskExecutor that uses virtual threads instead. Following these changes in Framework, SimpleAsyncTaskExecutor can be configured to use virtual threads by calling setVirtualThreads(true).

[rafaelrc7]

Hello, is this issue available for work? If so, I would like to ask if there is a specific way to check for virtual threads availability in spring-boot. Thanks.

[NicklasWallgren]

@wilkinsona
Would it be a viable option to set a ThreadFactory (which supports virtual threads) directly on the ThreadPoolTaskExecutor via a customizer?

The default coreSize (of 8) would still need to be tweaked.

You would then be able to take advantage of other functionality related to the ThreadPoolTaskExecutor, which isn't present in the AsyncTaskExecutor, such as awaitTermination.

POC main...NicklasWallgren:spring-boot:35710-virtual-threads-thread-pool-task-executor

[wilkinsona]

Thanks for suggestion but I don't think that's the right approach. The JEP has a section that explicitly states that virtual threads should not be pooled. As such, I think it would be confusing for Boot's default configuration when virtual threads are enabled to use a ThreadPoolTaskExecutor with a virtual thread factory.

If you believe that awaitTermination would be useful, you may want to suggest it as an enhancement to the Spring Framework team.

[NicklasWallgren]

Alright, seems reasonable. Thanks!

[vladimirfx]

I've tested virtual threads support in 3.2.0-M1 and missing support for TaskScheduler. No issue was found for virtual threads in scheduling either.

Is it planned to use virtual threads for scheduled tasks?

[vladimirfx]

Currently, I've used this bean definition as a workaround for task scheduling:

    bean<ConcurrentTaskScheduler>(name = "taskScheduler", isLazyInit = true) {
        ConcurrentTaskScheduler(Executors.newScheduledThreadPool(0, Thread.ofVirtual().factory()))
    }