Software Architecture: The Hard Parts

High static coupling implies that the elements inside the architecture quantum are tightly wired together, which is really an aspect of contracts.

While experience is useful, scenario analysis is one of an architect’s most powerful tools to allow iterative design without building whole systems. By modeling likely scenarios, an architect can discover if a particular solution will, in fact, work well.

Static coupling Represents how static dependencies resolve within the architecture via contracts. These dependencies include operating system, frameworks, and/or libraries delivered via transitive dependency management, and any other operational requirement to allow the quantum to operate.

Architects must watch out for composite architecture characteristics—ones that aren’t objectively measurable but are really composites of other measurable things. For example, “agility” isn’t measurable, but if an architect starts pulling the broad term agility apart, the goal is for teams to be able to respond quickly and confidently to change, ei

The authors built many distributed systems a few decades ago when they first became popular, yet decision making in modern microservices seems more difficult, and we wanted to figure out why. We eventually realized that, back in the early days of distributed architecture, we mostly still persisted data in a single relational database. However, in m

Architects shouldn’t constantly seek out silver-bullet solutions to their problems; they are as rare now as in 1986, when Fred Brooks coined the term: There is no single development, in either technology or management technique, which by itself promises even one order of magnitude [tenfold] improvement within a decade in productivity, in reliabilit

static coupling analyzes operational dependencies, and dynamic coupling analyzes communication dependencies.

An architecture quantum is an independently deployable artifact with high functional cohesion, high static coupling, and synchronous dynamic coupling. A common example of an architecture quantum is a well-formed microservice within a workflow.

Building services that model bounded contexts required a subtle but important change to the way architects designed distributed systems because now transactionality is a first-class architectural concern. In many of the distributed systems architects designed prior to microservices, event handlers typically connected to a single relational database