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Status
Current state: Draft Accepted
Discussion thread: here [Change the link from the KIP proposal email archive to your own email thread]
JIRA: here [Change the link from KAFKA-1 to your own ticket]
Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).
Motivation
Describe the problems you are trying to solve.
Public Interfaces
Briefly list any new interfaces that will be introduced as part of this proposal or any existing interfaces that will be removed or changed. The purpose of this section is to concisely call out the public contract that will come along with this feature.
A public interface is any change to the following:
Binary log format
The network protocol and api behavior
Any class in the public packages under clientsConfiguration, especially client configuration
org/apache/kafka/common/serialization
org/apache/kafka/common
org/apache/kafka/common/errors
org/apache/kafka/clients/producer
org/apache/kafka/clients/consumer (eventually, once stable)
Monitoring
Command line tools and arguments
- Anything else that will likely break existing users in some way when they upgrade
Proposed Changes
Request: provide subscribe(Pattern pattern) overload, similar to subscribe(Collection<String> topics),
Today, for a consumer to subscribe to topics based on a regular expression (i.e. Pattern), the only method option also requires to pass in a ConsumerRebalanceListener. This is not user-friendly to require this second argument. It seems new NoOpConsumerRebalanceListener() has to be used.
Use case: multi datacenter, allowing easier subscription to multiple topics prefixed with datacenter names, just by using a pattern subscription.
Public Interfaces
The org.apache.kafka.clients.consumer.KafkaConsumer class will have a new method overload: subscribe(Pattern pattern)
Proposed Changes
The org.apache.kafka.clients.consumer.KafkaConsumer class should have a new method overload: subscribe(Pattern pattern) that calls subscribe(Pattern pattern, ConsumerRebalanceListener listener) with new NoOpConsumerRebalanceListener() as the second argumentDescribe the new thing you want to do in appropriate detail. This may be fairly extensive and have large subsections of its own. Or it may be a few sentences. Use judgement based on the scope of the change.
Compatibility, Deprecation, and Migration Plan
- What impact (if any) will there be on existing users?
- If we are changing behavior how will we phase out the older behavior?
- If we need special migration tools, describe them here.
- When will we remove the existing behavior?
Rejected Alternatives
- No breaking change is expected.
- No mandatory migration is necessary.
- No existing behavior will be deprecated or removed.
Rejected Alternatives
n/aIf there are alternative ways of accomplishing the same thing, what were they? The purpose of this section is to motivate why the design is the way it is and not some other way.