[KAFKA-14264] Refactor coordinator code

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.4.0
• Component/s: clients, consumer
• Labels: consumer-threading-refactor
• Assignee: Philip Nee
• Reporter: Philip Nee
• Created: 28/Sep/22 02:23
• Updated: 20/Oct/23 00:40
• Resolved: 27/Feb/23 19:17

Description

To refactor the consumer, we changed how the coordinator is called.  However, there will be a time period where the old and new implementation need to coexist, so we will need to override some of the methods and create a new implementation of the coordinator.  In particular:

1. ensureCoordinatorReady needs to be non-blocking or we could just use the sendFindCoordinatorRequest.
2. joinGroupIfNeeded needs to be broken up into more find grain stages for the new implementation to work.

We also need to create the coordinator state machine.

Issue Links

• links to: GitHub Pull Request #12862