Fundamentals of Software Architecture

Chapter 7. Scope of Architecture Characteristics

A prevailing axiomatic assumption in the software architecture world had traditionally placed the scope of architecture characteristics at the system level. For example, when architects talk about scalability, they generally couch that discussion around the scalability of the entire system. That was a safe assumption a decade ago, when virtually all systems were monolithic. With the advent of modern engineering techniques and the architecture styles they enabled, such as microservices, the scope of architecture characteristics has narrowed considerably. This is a prime example of an axiom slowly becoming outdated as the software development ecosystem continues its relentless evolution.

During the writing of the Building Evolutionary Architectures book, the authors needed a technique to measure the structural evolvability of particular architecture styles. None of the existing measures offered the correct level of detail. In “Structural Measures”, we discuss a variety of code-level metrics that allow architects to analyze structural aspects of an architecture. However, all these metrics only reveal low-level details about the code, and cannot evaluate dependent components (such as databases) outside the code base that still impact many architecture characteristics, especially operational ones. For example, no matter how much an architect puts effort into designing a performant or elastic code base, if the system uses a database that ...