Timeless principles, agnostic design and the power of CAP's abstractions

I wrote recently about Hexagonal Architecture, alternatively known as Ports & Adapters, in Book Overflow and two architectural patterns in CAP. The core idea is based on having a deliberately agnostic approach to mechanisms, resources and services beyond - located in the outer concentric circles, as it were - a given core service. Think of this in a similar way to "late cut" integration, where the actual location, shape of, and connection to a required service is left until the last minute. The agnostic design approach is not new, and indeed as Daniel mentions in his keynote, has in the past been referred to as "minimal assumptions", which crops up in various disciplines, including statistics & data analysis, where it conveys the approach of "deriving valid conclusions using the fewest possible restrictive parameters"1. This approach brings many advantages, not least the ability for CAP developers to enjoy a tight and rapid development loop, where local-first is the mantra, and…