Applying the database-first variant of the Event Sourcing pattern with DynamoDB

In the previous recipe, Applying the event-first variant of the Event Sourcing pattern, we discussed how the Event Sourcing pattern allows us to design eventually consistent systems that are composed of a chain of atomic steps. Distributed transactions are not supported in cloud-native systems, because they do not scale effectively. Therefore, each step must update one, and only one, system. In this recipe, we will leverage the database-first variant of the Event Sourcing pattern, where the atomic unit of work is writing to a single cloud-native database. A cloud-native database provides a change data capture mechanism that allows further logic to be atomically triggered that publishes an appropriate domain event to the event stream for further downstream processing. In this recipe, we will demonstrate implementing this pattern with AWS DynamoDB and DynamoDB Streams.