net.leanix.dropkit.util.async

Class RetryExecutor

java.lang.Object

net.leanix.dropkit.util.async.RetryExecutor

public class RetryExecutor
extends Object

A helper executor class used to execute a block of code in another thread with a retry mechanism. In case the code block which is invoked in run(RetryTask) throws an exception, this block will be executed again after a defined delay until no exception arises.

Here is an example, how to use this class for a reliable webhooks subscription when a microservice starts:

  @Singleton
 public class WebhooksSubscriber implements Managed {
 
   private final RetryExecutor retryExecutor;
    
    @Inject
   public WebhooksSubscriber(AppConfiguration appConfiguration) {
      this.retryExecutor = new RetryExecutor();
   }
   
   protected void upsertSubscription(Subscription subscription) {
      retryExecutor.run((attemptCount) -> {
          try {
              Subscription existingSubscription = getSubscriptions(null, subscription.getIdentifier());
              if (existingSubscription == null) {
                  LOG.info("creating new webhooks subscription '{}'", subscription);
                  subscriptionsApi.createSubscription(subscription);
              } else {
                  LOG.debug("refreshing webhooks subscription '{}'", subscription);
                  subscriptionsApi.updateSubscription(existingSubscription.getId(), subscription);
              }
          } catch (ApiException e) {
              LOG.info("Could not subscribe to webhooks with attempt {}", attemptCount, e);
              throw e;
          }
      });
   }
  
    @Override
   public void stop() throws Exception {
      retryExecutor.stop();
   }
  ...
 }
 

Author:

ralfwehner

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RetryExecutor.ExpectedFailureException
static interface	RetryExecutor.RetryTask

Constructor Summary

Constructors

Constructor and Description
RetryExecutor()
RetryExecutor(int corePoolSize, int delayAfterFail, TimeUnit delayAfterFailUnit, String patternThreadFactory)

Method Summary

Modifier and Type	Method and Description
void	run(RetryExecutor.RetryTask task)
void	stop()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RetryExecutor

public RetryExecutor()

RetryExecutor

public RetryExecutor(int corePoolSize,
                     int delayAfterFail,
                     TimeUnit delayAfterFailUnit,
                     String patternThreadFactory)

Method Detail

stop

public void stop()
          throws InterruptedException

Throws:

InterruptedException

run

public void run(RetryExecutor.RetryTask task)