How to split records into different streams, from one topic to different streams?

Question

I have a single source CSV file containing records of different sizes that pushes every record into one source topic. I want to split the records into different KStreams/KTables

Answer 1

You can write a separated Kafka Streams application to split records from the input topic to different KStream or output topics using KStream#branch() operator:

KStream[] branches = streamsBuilder.branch(
        (key, value) -> {filter logic for topic 1 here},
        (key, value) -> {filter logic for topic 2 here},
        (key, value) -> true//get all messages for this branch
);

// KStream branches[0] records for logic 1
// KStream branches[1] records for logic 2
// KStream branches[2] records for logic 3

Or you could manually branch your KStream like this:

KStream inputKStream = streamsBuilder.stream("your_input_topic", Consumed.with(keySerde, valueSerdes));

inputKStream
        .filter((key, value) -> {filter logic for topic 1 here})
        .to("your_1st_output_topic");

inputKStream
        .filter((key, value) -> {filter logic for topic 2 here})
        .to("your_2nd_output_topic");
...