[KAFKA-17131] Cleanup `ProcessorContext` usage

• Type: Improvement
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Component/s: streams
• Labels: needs-kip
• Assignee: Matthias J. Sax
• Reporter: Matthias J. Sax
• Created: 12/Jul/24 23:52
• Updated: 6 days ago 04:05

Description

We did replace `Processor` and related classes with `api.Processor` et al. – However, there is also `ProcessorContext` which was deprecated via KIP-478 (AK 2.7) but not marked as deprecated as it was in use in many other places.

Many of the methods which used the old `ProcessorContext` got removed in AK 4.0 release, and some others are already deprecated.

However, `ProcessorContext` is still in use in internal code, and we should try to refactor internal code (especially for state stores) to move off the old interface, so we can eventually remove it (most likely in AK 5.0).

When we make `ProcessorContext` as deprecated, we can also mark `org.apache.kafka.streams.processor.To` helper class as deprecated, as it's only use by `ProcessorContext` (we need to do a KIP for this).

Issue Links

• is related to: KAFKA-9109 Get Rid of Cast from ProcessorContext to InternalProcessorContext
• is related to: KAFKA-17178 Update KTable.transformValues to new Processor API
• is related to: KAFKA-13722 Update internal interfaces that use ProcessorContext to use StateStoreContext instead
• is related to: KAFKA-13662 Migrate DeserializationExceptionHandler to latest ProcessorContext API
• relates to: KAFKA-12829 Remove Deprecated methods can classes of old Processor API
• relates to: KAFKA-16339 Remove Deprecated "transformer" methods and classes
• relates to: KAFKA-16279 Avoid leaking abstractions of `StateStore`
• links to: GitHub Pull Request #18241