Evolution without Big Bang: Hexagonal, Strangler and governance

Evolution without Big Bang: Hexagonal, Strangler and governance Series: Part 5 of 5 — CQRS and architecture for AI agents. Reading time: ~7 min. In the previous article we covered Event Sourcing and materialization in Elixir. This last article covers Hexagonal Architecture, Strangler Fig, Evolutionary Architectures, Fitness Functions, Ports & Adapters in practice, and closes the series with conclusion and takeaway. Hexagonal Architecture (Ports and Adapters) and surgical migrations Knowing that CQRS confines and compartmentalizes complexity addresses part of the problem; the ongoing challenge is dealing with dependent infrastructure without rigidifying the software. In this context the Hexagonal Architecture pattern fits orthogonally, also known as Ports and Adapters, conceived by Alistair Cockburn. The essence of Hexagonal Architecture strictly forbids infrastructure concerns, libraries and framework abstractions from leaking into domain logic (the core or hexagon). At the heart o