[FLINK-38447] Add table sink support for Elasticsearch 8 connector

[lwn3148]

Currently, the Elasticsearch 8 connector lacks a Table API sink implementation. This contribution adds a Table sink to the connector. To maintain configuration consistency with existing Elasticsearch connectors (e.g., ES 6/7), some utility classes and configuration definitions were directly reused from the base module, but the configuration options are adapted to the capabilities of the Elasticsearch8AsyncSink.

Key configuration changes include:

Removed options not supported by Elasticsearch8AsyncSink:

• sink.bulk-flush.backoff.strategy
• sink.bulk-flush.backoff.max-retries
• sink.bulk-flush.backoff.delay

Added new options:

• sink.bulk-flush.max-buffered-actions
• ssl.certificate-fingerprint

Retained and aligned all other options with the Elasticsearch8AsyncSink configuration.

[boring-cyborg]

Thanks for opening this pull request! Please check out our contributing guidelines. (https://flink.apache.org/contributing/how-to-contribute.html)

[daniq87]

Is there an ETA for merging this ? I see there is a single commit from Sep 27th.
We are trying to upgrade or ElasticSearch instance from 7.X to 8.X but we are blocked because of this.

Keep in mind that 7.17.11 version is under End of maintenance since April 15th 2025 and it will reach End of support term next Jan 15 2026

[lwn3148]

This PR has been open for a while. Would you be able to review this PR when convenient? @liuml07 @mtfelisb

[liuml07]

I can take a look after Thanksgiving. But I do not have write permission, so a second review is required.

[lwn3148]

Thanks! Enjoy the holiday!

I can take a look after Thanksgiving. But I do not have write permission, so a second review is required.