We build increasingly sophisticated architectures and web applications but rely on HTTP and the humble string to hold them together. We apply widely understood data formats (XML, JSON) to our requests and responses so both sides understand structure but how does each party declare its expectations of the content of the message? What’s more, how do we avoid a excessive coupling between components and the data formats they share?

Attendees of this talk will come away with a better understanding of why it is so important to think about integration and an idea of some of the ways we can get smarter about the division of responsibilities in our systems. This will include tools and techniques like consumer contracts and generative testing that allow us to better reason about uncertainties, test our assumptions and localise faults in our systems.

Code smells in other languages like Java are well understood and documented but what about Clojure? Does the language make all these problems and smells go away? For many of us starting to write our first production Lisp, the territory is unfamiliar and smells are not immediately apparent. In this talk, I explain why we should start to think about Clojure smells and describe some of the patterns that might make the list. (Warning: may contain depictions of unsightly code and offensive parentheses.)

The goal of this talk is to start to start the discussion off about what kinds of smells and anti-patterns could show up in Clojure code, what to do about them and what they may tell you about underlying issues. I don’t intend to create a full catalogue, more to make a start and see what other anti-patterns other people have noticed.

References: Martin Fowler on Code Smells: https://martinfowler.com/bliki/CodeSmell.html (also the book chapter authored with Kent Beck in Refactoring https://www.amazon.com/Refactoring-Improving-Design-Existing-Code/dp/0201485672)