This repository contains an example application that demonstrates how to implement an Event-sourced system using the Axon stack. The Axon stack consists of the Axon Framework, which is used to build the application, and the Axon Server, which is a zero-configuration event store that works out-of-the-box.
The application is implemented on top of Spring Boot and uses the Spring Boot starter for Axon. The programming model of Axon integrates quite nicely with what we expect from a Spring experience - hopefully, you'll see this yourself by consulting the code.
Projections are stored using an in-memory H2 database.
The application itself is minimalistic and implements a simple todo list that allows you to create and close todo items.
First of all, make sure that Docker as well as Docker Compose is installed on your system.
Before you start the example application, you should make sure that you have an instance of Axon Server running. To get you started quickly, this repository contains a docker-compose.yml script that launches Axon Server and exposes the necessary ports to the host system.
Go to src/main/docker and run
$> docker-compose runIf you haven't done this before, this will pull Axon Server 4.2 from DockerHub. After the image is available on your local system, Axon Server should be up and running in a matter of seconds.
Stopping Axon Server is done via
$> docker-compose stopand the remaining container (if you won't fire it up again or want to start with a clean slate) can be removed with
$> docker-compose rm -fThe Axon Dashboard is available at localhost:8024 once Axon Server has been successfully started.
After that, you can start the example application using Maven from the root of the repository.
$> mvn spring-boot:runOf course, you can also build the application via mvn clean install and start the resulting fat JAR.
The application comes with a OpenAPI integration that is available at localhost:8080/swagger-ui.html once the application has successfully started. The API is documented, so you should be able to figure things out for yourself.
The application can be inspected using the Axon Dashboard of your locally running Axon Server instance. Just go to http://localhost:8024, click on the Overview selector in the menu bar to the left and you should see a single connection from the application to Axon Server.
The example application has the H2 console configured. You can take a look at the database at http://localhost:8080/h2-console, connect to the JDBC URL jdbc:h2:mem:testdb and see for yourself what the individual projections store.
This work is released under the terms of the Apache 2.0 license.