Workshop on Event-Driven Design in Madrid

A few days ago I ran a small workshop on software design for the awesome folks at h4ckademy.

Audience was very diverse - heterogeneous backgrounds, different levels of experience (recent college graduates and professionals with 10+ years in software) and different minds (from designers to console hackers).

We decided to run a crash course in software design, focusing on the practical ideas that could be explained quickly and in a coherent manner.

EDD Workshop in Madrid

The plan looked like this:

  1. Essence of software design - principles of Domain-Driven Design, fast iterations, importance of feedback, focus on contexts, boundaries and contracts. Divide and conquer. Domain events and API contracts as the core part of interchange contexts.
  2. Event Storming Session - collaborative exercise on analyzing a new business domain and building a useful model: contexts, domain events, API contracts.
  3. Practical application of event-driven model - split domain implementation into modules; capture behaviors with runnable specifications expressed via domain-events and API contracts; scale design to handle more features, team members and higher loads; high availability.
  4. CQRS Beers - an informal discussion, focused on QA, actual code and implementation details. We talked about ReactJS/Flux vs AngularJS and the other MV* frameworks, career paths of a developer, building reputation, working remotely and dealing with burn-outs.

The workshop went well, I enjoyed presenting to such a diverse audience and doing exercises together. Many thanks to Israel Gutiérrez for inviting me over for such an event.

What could be improved

To make this workshop better:

  • allocate more time for the same amount of material (we had to rush through some concepts) or reduce the amount of material for this time-frame;
  • explore more than one problem domain in exercises, switching people between teams;
  • dedicate a block of ~15-20 minutes to front-end problems and designs.

Things that worked out very well and should be kept:

  • mixing presentations with QA and collaborative exercises - this allows to keep people more involved in the process, cover more material;
  • CQRS Beers - that format works very well for relaxed discussions (as proven by the years of experience :) );
  • event-storming - it is one of the best parts of the design process, thanks to the EU DDD community, there is a lot of fun and interactivity;
  • following the reasoning sequence from "foundational design principles at bird-view" to "collaborative design exercise" and then to "practical applications"; maybe it could be extended with hand-on exercises for longer workshops.

References

These additional materials contain more information on the topics covered during the workshop. They can also provide answers to some questions we didn't have time to address.

  • HappyPancake Story - story of a HappyPancake project, covering many aspects of event-driven design, "micro-services", specifications and event-driven UI. Check this story, the others and simply browse the site.
  • Being The Worst - light-hearted podcast on domain-driven design, implementation patterns and learning how to build a task manager. We are still doing it.
  • Domain-driven Design - the foundational book by Eric Evans on DDD methodology and related patterns. Start reading it with the chapter on context Mapping. Keep in mind that "Domain Events" weren't considered to be very important when the book was written (things have changed since then).
  • Implementing DDD - newer book by Vaughn Vernon, addressing some concerns and questions which appeared since the "Blue Book" came out. Don't read the appendix on Event Sourcing, material there is very outdated.
  • Ziobrando's Lair - blog by Alberto Brandolini, a great guy and an experienced DDD practitioner that coined term "event storming".
  • Sample TODO app in ReactJS/Flux - front-end sample that I showed during the CQRS Beers. It is work in progress.
  • Sample modular backend for TODO app - work in progress, but already includes these specification tests I showed during the workshop.

References above are most closely aligned with the material given during the workshop. If you have more specific questions, please don't hesitate to get in touch.

Responses

h4ckademy:

Very funny workshop about event-driven design with @abdullin Enjoying it a lot!

h4ckademy:

... A lot of fun and learning, both at the workshop and the beers!

Ruben H:

Great fun yesterday learning EDD with @abdullin at @h4ckademy

Feedback

Anonymous:

  • What did you like the most? When you explained how to implement a microservices architecture with a DDD approach.
  • What else would you like to hear about? More in depth event treatment, techniques and tools.

Anonymous:

  • What did you like the most? I liked a lot a general map of how the architecture is made. It was very clear, and interesting. Also i enjoyed play with the architecture over the table splitted in teams of a company, it's great to have a hands-on game.
  • What could make this workshop better for you? The workshop was excellent, but to make it even better, maybe could be possible to make a little application or at least the basic architecture of event driven design, just to have a feeling with the architecture.
  • What else would you like to hear about? I would like to know more use cases and maybe a real stories of implementing this kind of architecture in real projects.

Ruben H:

  • What did you like the most? First part, where you explained how to design an app/software using DDD.
  • What could make this workshop better for you? More time on event-storming session.
  • What else would you like to hear about? Compare DDD to other methods that also allow to design and implement app/software.

Víctor Pérez:

  • What did you like the most? It gives you a general overview of how to join bussiness and development worlds in a verbose way.
  • What could make this workshop better for you? Maybe longer, but it was already adjusted to our needs, so maybe there's no reason for changes.

Rubén Antón:

  • What did you like the most? The explanation was really good and easy to follow for everyone. But the part I liked the most was the event storming one. It showed off how valuable can be in order to understand the domain and the acceptance tests we could write later on.
  • What could make this workshop better for you? I'd love to hear more about the architecture inside the microservices.
  • What else would you like to hear about?

If you were at the workshop and want to share your feedback, please don't hesitate to get in touch with me via twitter @abdullin or email:rinat@abdullin.com.

- by .