Enhancement Request: Customizable groupExecutorService in Resilience4J CircuitBreakerFactory

[imyzt]

Is your feature request related to a problem? Please describe.

When incorporating openfeign and circuitbreaker in a spring-boot project, our code submits tasks to the executorService for execution. The executorService is created using Executors.newCachedThreadPool(). We intend to customize this thread pool to propagate ThreadLocal information from the main thread to the child threads.

While the Resilience4JCircuitBreakerFactory#configureExecutorService method allows reconfiguration of the thread pool, the groupExecutorService is hard-coded in the code and lacks extensibility, making it challenging to fully implement the desired functionality.

Describe the solution you'd like

We propose making the groupExecutorService customizable or providing a mechanism for extension so that developers can seamlessly implement customizations to pass ThreadLocal information to the child threads.

Additional Information:

Code Reference: Resilience4JCircuitBreakerFactory#configureExecutorService
Current Limitation: Inability to customize groupExecutorService for complete functionality implementation.
Expected Outcome:
We request enhancements to the Resilience4J CircuitBreakerFactory to allow developers to easily customize the groupExecutorService or provide an extension mechanism to fulfill the requirement of passing ThreadLocal information to child threads.

Sample code：

@Configurable
@AllArgsConstructor
public class CircuitBreakerConfiguration implements ApplicationRunner {

    private final Resilience4JCircuitBreakerFactory factory;
    
    @Override
    public void run(ApplicationArguments args) throws Exception {

        ContextThreadPoolExecutor contextThreadPoolExecutor = 
                new ContextThreadPoolExecutor(2, 5, 1, TimeUnit.MINUTES, new ArrayBlockingQueue<>(1024));

        // **change ThreadPoolExecutor**
        factory.configureExecutorService(contextThreadPoolExecutor);
    }
    
    public static class ContextThreadPoolExecutor extends ThreadPoolExecutor {

        public ContextThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) {
            super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
        }

        public void execute(Runnable command) {
            super.execute(wrap(command));
        }

        private static Runnable wrap(Runnable runnable) {
            **SubjectContext context = SubjectContext.getContext();**
            return () -> {
                **SubjectContext.setContext(context);**
                try {
                    runnable.run();
                } finally {
                    **SubjectContext.clear();**
                }
            };
        }
    }
}

@Override
public org.springframework.cloud.client.circuitbreaker.CircuitBreaker create(String id) {
    Assert.hasText(id, "A CircuitBreaker must have an id.");
    Resilience4JCircuitBreaker resilience4JCircuitBreaker = create(id, id, this.executorService);
    return tryObservedCircuitBreaker(resilience4JCircuitBreaker);
}

@Override
public org.springframework.cloud.client.circuitbreaker.CircuitBreaker create(String id, String groupName) {
    Assert.hasText(id, "A CircuitBreaker must have an id.");
    Assert.hasText(groupName, "A CircuitBreaker must have a group name.");
    // **Fixed thread pool creation method, unable to expand**
    final ExecutorService groupExecutorService = executorServices.computeIfAbsent(groupName,
            group -> Executors.newCachedThreadPool());
    Resilience4JCircuitBreaker resilience4JCircuitBreaker = create(id, groupName, groupExecutorService);
    return tryObservedCircuitBreaker(resilience4JCircuitBreaker);
}

[ryanjbaxter]

Would you be interested in submitting a PR for this?

[imyzt]

@ryanjbaxter Of course, Please read my code to ensure it can run in any scenario. #181
Thanks.

[yong-kurly]

@ryanjbaxter
I think this patch should be applied in 3.1.x as well.

[ryanjbaxter]

@yong-kurly it was see 5fa638e

[yong-kurly]

Ah! Sorry.
3.1.1 version has not been released, so I though it was not.

I'm looking forward 3.1.1 release!

[yong-kurly]

Just curious: May I know when the new version(3.1.x) will be released? I am waiting for this feature. 🙏

[ryanjbaxter]

This week.