Apache Pekko Persistence with Scala

This example illustrates event sourcing with Apache Pekko Persistence.

Study the source code of the ShoppingCart.scala. A few things to note:

  • The actor is implemented with the EventSourcedBehavior
  • It defines Command, Event and State
  • Commands define replyTo: ActorRef to send a confirmation when the event has been successfully persisted
  • State is only updated in the event handler
  • withRetention to enable snapshotting
  • onPersistFailure defines restarts with backoff in case of failures

Tests are defined in ShoppingCartSpec.scala. To run the tests, enter:

sbt:pekko-sample-persistence-scala> test

The ShoppingCart application is expanded further in the pekko-sample-cqrs-scala sample. In that sample the events are tagged to be consumed by even processors to build other representations from the events, or publish the events to other services.