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Charlotte Hibert

Erwin de Gier

Reactive CQRS and Event Sourcing [Workshop]

Charlotte Hibert & Erwin de Gier - Trifork

Using events is a powerful alternative to REST-based communication in microservices. However, it comes with its own challenges: For instance, dealing with eventual consistency, synchronisation of state, and writing code which can handle asynchronous business logic.

In this workshop we will use Spring 5’s powerful reactive features (such as WebFlux and Project Reactor) to build an event-driven microservice application. We make use of the Axon Framework for implementing CQRS and Event Sourcing. Spring WebFlux is used to handle scenarios were we need the translation from asynchronous domain services to synchronous responses in the mobile app. We chose this approach, because it provides a better user experience when feedback is immediately available after performing an action.

In the workshop we will make use of a working sample application. In different exercises the attendees will add features to this application.

The attendees of this workshop can expect to learn about: - How reactive programming helps with asynchronous flows
- How to use Spring WebFlux with CQRS and Event Sourcing
- How to use Axon framework together with the Spring stack


- JDK 8 or higher
- Docker

Nice to have:

CQRS & Spring experience