I heard someone mentioning Eric Evans and DDD (Domain Driven Design) a few times and so I decided to see what’s its all about. It took me a while to get through the book, partly because I’m a slow reader, partly because the book is long and partly because the read is dry. As I was working through the book, I often wondered to myself: “is this still relevant?”.
Lots of described techniques are common place in everyday software development, however some of them evolved, for example: Microservice. It represents a bounded-context and due to the nature of a microservice, it is separated and doesn’t share objects or internals. Translators, entities, value objects and aggregates are fairly standard on projects I’ve been in so far. Layered architecture, frameworks, team work, supplier-consumer team relations, managers, refactoring and ivory tower architects are fascinating subjects, but again been there and done that. I’m not a history buff but I do enjoy it and so I find myself smiling reading through some parts, lets not forget the book is almost 20 years old. I did find an answer to one lurking question I had for a while: “why less capable engineers tend to accumulate in a legacy but still important, core software systems?” and let me say, Eric nailed it.
So some techniques might be dated but in my mind still relevant, however all of it is just peripheral stuff. What about the core? What about domain? Well this is where things get muddy for me. As I read through examples and discussions, I understood the value of good design, born in ubiquitous language, with help of business specialists, capable fearless engineers with commitment to deep thinking and forever deepening understanding of a business model. In theory DDD is the best thing that can ever happen on a project, however in reality (and by some degree of the author’s own admissions and disclaimers), DDD is not always the best choice or even a possibility. In my mind too many things must align in order for DDD to happen and bare fruit. In any system with many moving parts, there are things that can and typically will go wrong, especially when we are talking about creative work and human operated system.
But is the book still relevant? I think so, I would not be putting it on the top of “must read before programming”, but it still be on the list. I’m sure that commitment to deep thinking and modelling will not be going away any time soon. On top of it, perhaps as an industry we are no long bounded by monolith, but bounded-context is here to stay in one form or another.
In a nutshell:
-: long, dry read
-/+: relevance of some ideas in present software development
+: methodology to design and implementation
+: covers lots of aspects of system development
+: plenty of discussions
=: the book is good, I think people aspiring to be or current architects will reap lots of benefits. Few things feel dated but lots is still very much applicable and valuable. There are lots of books and materials that hold (IMHO) more value for developers in early and middle stages of learning the craft. But at some point Domain Driven Design should be considered.
Title: Domain-Driven Design: Tackling Complexity in the Heart of Software
Author: Eric Evans
I took few notes during the read: