api.md

kafka-streams.js Documentation

1. Relation to most.js

   • Similarities

2. Relation to JAVA (kafka) kafka-streams

   • Similarities

3. Relation to Flink

   • Similarities

4. How to get started

   • Getting started
   • Using the examples

5. Documentation (is still WIP)

   • Dealing with Message Schemas
   • HTML-Documentation
   • MD-Documentation
   • Using the native client
   • SSL support
   • SASL and Kerberos

1. most.js

Relation to most

Both KStream and KTable classes depend on StreamDSL that internally wraps around most.js's observable/stream as .stream$ class-member.

A large amount of stream operators that most.js offers are available as functions of KStream & KTable - however they are not always equal and they NEVER return a new KStream or KTable instance -> this is a big difference compared to most.js.

Join and window operatios, like .merge() and .window() actually do return a new KStream or KTable instance as of their nature.

You can find the most.js project here

2. Apache kafka-streams

Relation to kafka-streams

In its core kafka-streams.js tried to adopt the behaviour and API of the original kafa-streams lib that is part of Kafka. Due to the nature of NodeJS and observables to decision was made to simply mimic the API of the original, but not exactly port it 1:1.

Therefore you can expect almost the same functionality under key-components like KStream and KTable but not exactly the same API. E.g. KafkaStreams's role as factory.

You can find the Apache Kafka project here

3. Apache Flink

Relation to Flink

Kafka-streams actually implements the concept of ẁindows to enable merge operations. However the Flink project (also a stream-processing framework similar to kafka-streams) has a different and more advanced approach at windows. kafka-streams.js offers window operations to merge streams, but it also tries to offer additional windowing features similar to what Flink offers.

You can find the Apache Flink project here

4. How to get started

Getting started

A good place to start using this lib is the Quick Start Tutorial, besides the examples.

The examples

The /examples should work out of the box, however they require you to have a local-setup that works with the tests. So take a quick look at /test/test-config.js and if you do not yet have a local Zookeeper + Kafka Broker running, take a look at /kafka-setup/docker-compose.yml running ./start.sh will start a local combination.