[Doc] Pulsar consumer config is missing to enable retry while mentioning retryletter config

[sundar-ka]

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What issue do you find in Pulsar docs?

Issue found in Pulsar docs

While reading the examples for DeadLetterPolicy and retry/DLQ handling, I noticed that the documentation can be misleading about when .enableRetry(true) is required.

Currently, some examples show configuration of:

• retryLetterProducerBuilderCustomizer(...)
• retryLetterTopic(...)

without calling .enableRetry(true).

Example of confusing snippet

// enable batch and disable chunking for the dead letter topic producer
// by default, the batch feature is disabled and the chunking feature is enabled
DeadLetterProducerBuilderCustomizer producerBuilderCustomizer = (context, producerBuilder) -> {
    producerBuilder.enableBatching(true);
    producerBuilder.enableChunking(false);
};
Consumer<byte[]> consumer = pulsarClient.newConsumer(Schema.BYTES)
                .topic("my-topic")
                .subscriptionName("my-subscription")
                .subscriptionType(SubscriptionType.Shared)
                .deadLetterPolicy(DeadLetterPolicy.builder()
                      .maxRedeliverCount(maxRedeliveryCount)
                      .deadLetterTopic("my-dead-letter-topic-name")
                      .deadLetterProducerBuilderCustomizer(producerBuilderCustomizer)
                      .retryLetterProducerBuilderCustomizer(producerBuilderCustomizer)
                      .build())
                .subscribe();

What is your suggestion?

Example of suggested snippet

// enable batch and disable chunking for the dead letter topic producer
// by default, the batch feature is disabled and the chunking feature is enabled
DeadLetterProducerBuilderCustomizer producerBuilderCustomizer = (context, producerBuilder) -> {
    producerBuilder.enableBatching(true);
    producerBuilder.enableChunking(false);
};
Consumer<byte[]> consumer = pulsarClient.newConsumer(Schema.BYTES)
                .topic("my-topic")
                .subscriptionName("my-subscription")
                .subscriptionType(SubscriptionType.Shared)
                .enableRetry(true)
                .deadLetterPolicy(DeadLetterPolicy.builder()
                      .maxRedeliverCount(maxRedeliveryCount)
                      .deadLetterTopic("my-dead-letter-topic-name")
                      .deadLetterProducerBuilderCustomizer(producerBuilderCustomizer)
                      .retryLetterProducerBuilderCustomizer(producerBuilderCustomizer)
                      .build())
                .subscribe();

I wrote pr: apache/pulsar-site#1041

I'm new to using pulsar. Kindly take a look and feel free to give me advice.

Any reference?

Are you willing to submit a PR?

• I'm willing to submit a PR!