When annotation Async and Lock coexist, there will be problems

[alturkovic]

When annotation Async and Lock coexist, there will be problems

[alturkovic]

Could you explain in more details what the issue is please? What kind of problems occur with @Async and @Locked?

[chenlingmin]

He will cause the lock to be implemented first, and then to enable asynchronous threads.

This will invalidate the lock.

  |        +-------------------------------------------+
  |        | Lock:Thread-1                             |
  |        |    +-----------------------------------+  |
  |        |    | Async:Thread-2                    |  |
  |        |    |   +----------------------------+  |  |
  |        |    |   | method:Thread-2            |  |  |
  |        |    |   +----------------------------+  |  |
  |        |    +-----------------------------------+  |
  |        +-------------------------------------------+
  ↓

[alturkovic]

Sorry for the late reply. You can extract the logic to be locked in a new service and annotate that method using @RedisLocked instead. That behaviour is pretty similar to @Transactional behaviour to control transactional logic so I am not sure this requires any changes since it can be mitigated.

[chenlingmin]

Currently, I have changed the Order value of LockBeanPostProcessor so that it can work before AsyncAnnotationBeanPostProcessor, This solution works.

Like this

  @Bean
    public LockBeanPostProcessor lockBeanPostProcessor(
            final ConfigurableBeanFactory configurableBeanFactory,
            final KeyGenerator keyGenerator,
            @Autowired(required = false) final TaskScheduler taskScheduler) {
            LockBeanPostProcessor lockBeanPostProcessor  = new LockBeanPostProcessor(new BeanFactoryAwareIntervalConverter(configurableBeanFactory), configurableBeanFactory::getBean, keyGenerator, taskScheduler);
            lockBeanPostProcessor.setOrder(Ordered.LOWEST_PRECEDENCE - 10);
            return lockBeanPostProcessor;
    }

But this method is not elegant enough, it is best to set LockBeanPostProcessor according to whether there is Transactional or Async

[alturkovic]

I understand your point, but I think you already noticed yourself that it won't really be possible to get the right order for each application. According to a comment here: Spring project's aspects do not have advice ordering guaranteed. And this is the same argument I am making.

How about something like this:

@Autowired
private LockedService lockedService;

@EventListener
@Async
public void sendEmail(XXXEvent event) {
    lockedService.sendEmail(event);
}

class LockedService {

  @RedisLocked
  public void sendEmail(XXXEvent event) {
  }

}

[chenlingmin]

Thank you, your solution is better, but users need to pay attention to the order of aspects.

Expect Spring to provide a more systematic solution.😂

[alturkovic]

I think we reached an acceptable conclusion so I am going to close this issue for now.