In Dunning & Friedman’s book Streaming Architecture, they state “a big difference between stream-based and traditional design … is that messaging layer plays a much more prominent role.”
I am streaming architecture’s biggest fan. So many possibilities open up when you de-couple producers from consumers, and let your messaging layer do the heavy lifting on persisting events. To get at some of the finer points I thought it could be fun to compare the open source project Apache Kafka with AWS’ pay-to-play Kinesis. Rather than put a firm barrier between the two, I’d like to move back and forth between them as we build a clearer picture of streaming architecture in action. But first, some facts about each.
Language-support & Installation for Kafka
Before we go to far, let’s get real about language-support. When I first used Kafka, I worked with a Python client called kafka-python, and there’s also Parsely’s pykakfa, amongst others. The being said, you will quickly follow the documentation breadcumbs back to their source, and see that Kafka is written in Scala and Java, and the best documentation on the block (written by Confluent) assumes you are developing in Scala or Java. Even if you plan to work with a Python client, I encourage you install the Confluent platform so you can follow along with their support documentation.
Replaying a kafka topic from a given offset (the unique identifier of a record in a paritition) is one of the great features that shows of Kafka’s persistance. But how do we do it?
A whole world of opportunities open up with Kafka Stream, as the duality of streams and tables (one being able to transform into the other) creates many possibilities for creating streams with enriched, processe data.
Perhaps the biggest terminology is that Kinesis has streams, where Kafka has topics. Kinesis streams can be partitioned into shards, and each shared has it’s own unique partition key. Shards are composed of data records, and each data record is composed of a unique sequence number, partition key, and data blob.