Background knowledge

A consumer is a process that attaches to a topic via a subscription and then receives messages. The reader interface for Pulsar enables applications to manually manage cursors. More knowledge of the Reader and Consumer interface can be found in the Pulsar Client doc.

Motivation

Add the getLastMessageIds API for Reader. This will help to increase the flexibility of reader usage.

Goals

In Scope

Add the getLastMessageIds API for Reader.

Out of Scope

None.

High Level Design

Implement the getLastMessageIds method for Reader by internally invoking the Consumer interface.

Detailed Design

Design & Implementation Details

    @Override
    public List<TopicMessageId> getLastMessageIds() throws PulsarClientException {
        return consumer.getLastMessageIds();
    }

    @Override
    public CompletableFuture<List<TopicMessageId>> getLastMessageIdsAsync() {
        return consumer.getLastMessageIdsAsync();
    }

Public-facing Changes

Public API

    /**
     * Get all the last message id of the topics the reader subscribed.
     *
     * @return the list of TopicMessageId instances of all the topics that the reader subscribed
     * @throws PulsarClientException if failed to get last message id.
     * @apiNote It's guaranteed that the owner topic of each TopicMessageId in the returned list is different from owner
     *   topics of other TopicMessageId instances
     */
    List<TopicMessageId> getLastMessageIds() throws PulsarClientException;

    /**
     * The asynchronous version of {@link Reader#getLastMessageIds()}.
     */
    CompletableFuture<List<TopicMessageId>> getLastMessageIdsAsync();

Binary protocol

Configuration

CLI

Metrics

Monitoring

Security Considerations

Backward & Forward Compatibility

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Alternatives

General Notes

Links

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