Hi all,
Here is a suggest (PIP) on consumers can set custom retry delay when
consumer fail.
------------
PIP 58 : Support Consumers Set Custom Retry Delay
## Motivation
For many online business systems, various exceptions usually occur in
business logic processing, so the message needs to be re-consumed, but
users hope that this delay time can be controlled flexibly. The current
user's processing method is usually to send this message to a special retry
topic, because production can specify any delay, so consumers subscribe the
business topic and retry topic at the same time. I think this logic can be
supported by pulsar itself, making it easier for users to use, and it looks
like this is a very common requirement.
## Proposed changes
This change can be supported on the client side, need to add a set of
interfaces to org.apache.pulsar.client.api.Consumer
```java
void reconsumeLater(Message<?> message, long delayTime, TimeUnit unit)
throws PulsarClientException;
CompletableFuture<Void> reconsumeLaterAsync(Message<?> message, long
delayTime, TimeUnit unit);
CompletableFuture<Void> reconsumeLaterAsync(Messages<?> messages, int
delayLevel);
CompletableFuture<Void> reconsumeLaterCumulativeAsync(Message<?> message,
long delayTime, TimeUnit unit);
```
DeadLetterPolicy add retry topic
```java
public class DeadLetterPolicy {
/**
* Maximum number of times that a message will be redelivered before
being sent to the dead letter queue.
*/
private int maxRedeliverCount;
/**
* Name of the retry topic where the failing messages will be sent.
*/
private String retryLetterTopic;
/**
* Name of the dead topic where the failing messages will be sent.
*/
private String deadLetterTopic;
}
```
org.apache.pulsar.client.impl.ConsumerImpl add a retry producer
```java
private volatile Producer<T> deadLetterProducer;
private volatile Producer<T> retryLetterProducer;
```
Can specify whether to enable retry when creating a consumer，default
unenable
```java
@Override
public ConsumerBuilder<T> enableRetry(boolean retryEnable) {
conf.setRetryEnable(retryEnable);
return this;
}
```
------------
Thanks,
Dezhi
