[KAFKA-9776] Producer could automatically downgrade TxnOffsetCommitRequest with internal flag

• Type: Sub-task
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.6.0
• Component/s: producer
• Assignee: Boyang Chen
• Reporter: Matthias J. Sax
• Created: 27/Mar/20 18:35
• Updated: 03/Apr/20 17:33
• Resolved: 03/Apr/20 17:33

Description

When using transactions with a 2.5 producer against 2.4 (or older) brokers, it is not possible to call `producer.commitTransaction(..., ConsumerGroupMetadata)` but only the old API `producer.commitTransaction(..., String applicationId)` is supported.

This implies that a developer needs to know the broker version when writing an application or write additional code to call the one or the other API depending on the broker version (the developer would need to write code to figure out the broker version, too).

We should change the producer to automatically downgrade to the older TxnOffsetCommitRequest if `commitTransaction(..., ConsumerGroupMetadata)` is used against older brokers to avoid an `UnsupportedVersionException`.

Issue Links

• links to: GitHub Pull Request #8375