Custom Kafka Streams State Restore Logic

[Upesh Desai]

Hello all,

I am currently working on creating a new InMemoryWindowStore, by extending the 
default in memory window store. One of the roadblocks I’ve run into is finding 
a way to add some custom logic when the state store is being restored from the 
changelog. I know that this is possible if I completely write the store logic 
from scratch, but we really only want to add a tiny bit of custom logic, and do 
not want to have to replicate all the existing logic.

Is there a simple way for this to be done? I see the default implementation in 
the InMemoryWindowStore :

context.register(
    root,
    (RecordBatchingStateRestoreCallback) records -> {
        for (final ConsumerRecord<byte[], byte[]> record : records) {
            put(
                Bytes.wrap(extractStoreKeyBytes(record.key())),
                record.value(),
                extractStoreTimestamp(record.key())
            );
            ChangelogRecordDeserializationHelper.applyChecksAndUpdatePosition(
                record,
                consistencyEnabled,
                position
            );
        }
    }
);


Thanks in advance!
Upesh

Upesh Desai
Senior Software Developer
ude...@itrsgroup.com
www.itrsgroup.com
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