Example projects using the Kafka extension

Axon Framework
1

Hi All,

Please share links to open source projects which use the Kafka extension.
We are looking to make use of it in our project and want to see illustrative examples with other people’s code to get a better idea of its usage.

I’ve created this thread with the intent of it being a reference one for links. Hopefully over time it grows and other people searching are redirected here!

Thanks!

2

Hi,

There is the example from the main repo. Additionally you might take a look at this branch, which had a few modules using the extension. Is there anything in particular you are looking for?

3

Hi,

I guess my initial questions are quite basic:

  • Can you use Kafka as the actual EventStore with the Axon Framework?
  • Or do you use it only for event listening components (to maintain projections/etc)?
  • When using Kafka to distribute messages, what is the normal way to do the message routing for commands and queries? Do people usually use Axon Server with Kafka?

I would much rather just use Axon Server but it is not possible in my current env.

4

With or without the Axon Framework, you can never use just Kafka as an event store. There is no concurrency control, and no efficient way to get the events for a single aggregate. The Kafka Extension only provides a distributed event bus using Kafka.

Typically it seems when using the Kafka Extension, either the JGroups or Spring Cloud extension is used for a distributed command bus. As there is no distributed query bus, except for the Axon Server one, they tend to not use queries, or only locally.