How to generate unique sequenceId for your application across multiple instances in KafkaStreams?

Question

I want to generate the unique ordered Id for what we are consuming from the topic, And it should be unique around multiple instances. (Not uuid)

Answer 1

Not sure why you don't wan to use a UUID. But you could use a combination of offset and partition number to compute a unique ID. Something like:

// you need to know upfront how many partitions the input topis has
private final static int NUMBER_OF_PARTITIONS = ...

// within `Transformer#transform()` using `KStream#transform()`
// (also consider to use #transformValues() instead).

// `context` is given via `init()`

long id = context.offset() * NUMBER_OF_PARTITIONS + context.partition();