Adam Warski, "Transactional event sourcing using Slick (audit log for free!)"

Description: Event sourcing is a great alternative to traditional “CRUD”-type architectures. The central concept is a persistent stream of events, which drives all changes to the read model and running any kind of business logic. There’s a lot of technical and business benefits to such an approach, such as being able to re-create the state of the system at any point in time, or keeping a detailed audit log of all actions.

Typically, implementations of event sourcing are presented using a NoSQL data storage, which is great for many use cases (e.g. using Akka Persistence + Cassandra). However, nothing stops us from using a relational database and SQL! In many applications (especially “enterprise”), this brings many benefits, such as powerful and familiar query capabilities and higher guarantees around data consistency.

In this mainly live-coding talk we’ll see one way of implementing transactional event sourcing using the `slick-eventsourcing` micro-framework, introducing the core concepts: command handlers, read model updates and event listeners, and how to use them to build an event-sourced application. We’ll see how Slick’s `DBAction` and Scala flexibility makes it possible to provide an elegant DSL to build the system from simple functions with minimum dependencies.

Adam about himself: "I am one of the co-founders of SoftwareMill, where I code mainly using Scala and other interesting technologies. I am involved in open-source projects, such as Macwire, Supler, ElasticMQ and others. I have been a speaker at major conferences, such as JavaOne, Devoxx and ScalaDays.

Apart from writing closed- and open-source software, in my free time I try to read the Internet on various (functional) programming-related subjects, any ideas or insights usually end up on my blog: http://www.warski.org/blog "

Schedule

• 6:30-7:00 - networking
• 7:00-7:10 - announcements etc
• 7:10-~8:40 - talk
• 8:40-9:00 - networking