How to Implement Custom Exponential Retry in Spring Boot with Kafka
Tags: webdev, programming, tutorial, java
Published: 2024-07-01 11:40:18

🧵 Struggling with custom exponential retries in your Spring Boot Kafka application? Here’s a quick guide to get it working! 🚀

1/7 🌱 **Dependency Setup**:
Ensure you have the necessary dependencies in your `pom.xml` or `build.gradle`. You need `spring-kafka` and `spring-retry`.

```xml
<dependency>
    <groupId>org.springframework.kafka</groupId>
    <artifactId>spring-kafka</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.retry</groupId>
    <artifactId>spring-retry</artifactId>
</dependency>
```

2/7 🛠️ **Configuration**:
Create a Kafka configuration class to set up retry policies. Use `RetryTemplate` for exponential backoff.

```java
@Configuration
public class KafkaConfig {

    @Bean
    public RetryTemplate retryTemplate() {
        RetryTemplate retryTemplate = new RetryTemplate();
        
        FixedBackOffPolicy backOffPolicy = new FixedBackOffPolicy();
        backOffPolicy.setBackOffPeriod(1000); // initial interval

        retryTemplate.setBackOffPolicy(backOffPolicy);
        retryTemplate.setRetryPolicy(new SimpleRetryPolicy(3)); // max attempts
        
        return retryTemplate;
    }
}
```

3/7 🔄 **Exponential Backoff Policy**:
For exponential backoff, use `ExponentialBackOffPolicy`.

```java
@Bean
public RetryTemplate retryTemplate() {
    RetryTemplate retryTemplate = new RetryTemplate();
    
    ExponentialBackOffPolicy backOffPolicy = new ExponentialBackOffPolicy();
    backOffPolicy.setInitialInterval(1000);
    backOffPolicy.setMaxInterval(10000);
    backOffPolicy.setMultiplier(2);
    
    retryTemplate.setBackOffPolicy(backOffPolicy);
    retryTemplate.setRetryPolicy(new SimpleRetryPolicy(3));
    
    return retryTemplate;
}
```

4/7 📥 **Consumer Factory**:
Integrate the `RetryTemplate` with your Kafka consumer factory.

```java
@Bean
public ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerContainerFactory() {
    ConcurrentKafkaListenerContainerFactory<String, String> factory =
        new ConcurrentKafkaListenerContainerFactory<>();
    factory.setConsumerFactory(consumerFactory());
    factory.setRetryTemplate(retryTemplate());
    return factory;
}
```

5/7 🏗️ **Consumer Factory Method**:
Define the consumer factory method as well.

```java
@Bean
public ConsumerFactory<String, String> consumerFactory() {
    Map<String, Object> props = new HashMap<>();
    props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
    props.put(ConsumerConfig.GROUP_ID_CONFIG, "group_id");
    props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
    props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
    return new DefaultKafkaConsumerFactory<>(props);
}
```

6/7 🎧 **Listener**:
Ensure your listener is configured properly to handle retries.

```java
@KafkaListener(topics = "topic_name", groupId = "group_id")
public void listen(String message) {
    // Your message handling logic
    System.out.println("Received message: " + message);
    // Simulate error for retry
    if (message.equals("retry")) {
        throw new RuntimeException("Simulated error");
    }
}
```

7/7 🎉 **Wrap Up**:
With these configurations, your Spring Boot Kafka application should now properly handle custom exponential retries.