Jdempotent

Goal of this Jdempotent-spring-boot-starter

Make your endpoints idempotent easily

Usage

1 - First of all, you need to add a dependency to pom.xml

    <dependency>
        <groupId>com.trendyol</groupId>
        <artifactId>Jdempotent-spring-boot-redis-starter</artifactId>
        <version>1.0.4</version>
    </dependency>

2 - You should add @IdempotentResource annotation to the method that you want to make idempotent resource, listener etc.

@IdempotentResource(cachePrefix = "WelcomingListener")
@KafkaListener(topics = "trendyol.mail.welcome", groupId = "group_id")
public void consumeMessage(@IdempotentRequestPayload String emailAdress) {
    SendEmailRequest request = SendEmailRequest.builder()
            .email(message)
            .subject(subject)
            .build();

    try {
        mailSenderService.sendMail(request);
    } catch (MessagingException e) {
        logger.error("MailSenderService.sendEmail() throw exception {} event: {} ", e, emailAdress);

        // Throwing any exception is enough to delete from redis. When successful, it will not be deleted from redis and will be idempotent.
        throw new RetryIdempotentRequestException(e);
    }
}

3 - If you want to handle a custom error case, you need to implement ErrorConditionalCallback like the following example:

@Component
public class AspectConditionalCallback implements ErrorConditionalCallback {

    @Override
    public boolean onErrorCondition(Object response) {
        return response == IdempotentStateEnum.ERROR;
    }
    
    public RuntimeException onErrorCustomException() {
        return new RuntimeException("Status cannot be error");
    }

}

4 - Let's make the redis configuration:

jdempotent:
  enable: true
  cache:
    redis:
      database: 1
      password: "password"
      sentinelHostList: 192.168.0.1,192.168.0.2,192.168.0.3
      sentinelPort: "26379"
      sentinelMasterName: "admin"
      expirationTimeHour: 2
      dialTimeoutSecond: 3
      readTimeoutSecond: 3
      writeTimeoutSecond: 3
      maxRetryCount: 3
      expireTimeoutHour: 3

Please note that you can disable Jdempotent easily if you need to. For example, assume that you don't have a circut breaker and your Redis is down. In that case, you can disable Jdempotent with the following configuration:

  enable: false

@SpringBootApplication(
      exclude = { RedisAutoConfiguration.class, RedisRepositoriesAutoConfiguration.class }
)

Performance

As it is shown in the following image, the most cpu consuming part of Jdempotent is getting a Redis connection so we don't need to worry performance related issues.

Docs

Jdempotent Medium Article
Jdempotent-core Javadoc
Jdempotent-spring-boot-redis-starter Javadoc

TODOS