[fix][client] Fix DLQ producer name conflicts when there are same name consumers

[geniusjoe]

Main Issue: apache/pulsar-client-go#1297
Relative #21890

Motivation

When multiple consumers with same name are using dlq policies at the same time, prompt will throw below exceptions:
ERRO[0069] Failed to create DLQ producer dlq-topic="persistent://<tenant>/<namespace>/<topic>-<subscription>-DLQ" error="server error: ProducerBusy: org.apache.pulsar.broker.service.BrokerServiceException$NamingException: Producer with name '-<subscription>-<consumerName>-DLQ' is already connected to topic"

Modifications

I think maybe we need to add a random suffix in dlq producer name like: opt.Name = fmt.Sprintf("%s-%s-%s-%s-DLQ", r.topicName, r.subscriptionName, r.consumerName, generateRandomName())

Verifying this change

• Make sure that the change passes the CI checks.

This change is already covered by existing tests, such as DeadLetterTopicTest.testDeadLetterTopicWithProducerName

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

After change golang, java and c++ sdks, we could update document like this pr https://github.com/apache/pulsar-site/pull/772/files.

Matching PR in forked repository

PR in forked repository:

[hanmz]

Can you add a test to verify this case that the consumer name is specified?

[geniusjoe]

Can you add a test to verify this case that the consumer name is specified?

@hanmz
I added a new test case testMultipleSameNameConsumersToDeadLetterTopic to test same name consumers situation. Please review again.

[lhotari]

This doesn't apply to 3.0.x since it doesn't include #21589