Elements of Sustainability for Public Sector Software – Mosaic Enterprise Architecture, Macroservices, and Low-Code

Abstract

Public sector is a large consumer for software. In countries such as Finland, many of the systems are made to order by consultancy companies that participate in public tenders. These tenders initiated by the state, cities, and other public sector organizations. Furthermore, as public sector tasks are often decomposed to various actors, each and every one of them makes their purchase based on their own needs. In this paper, we argue that to maintain software sustainability in this context, there is a need for three key elements. Firstly, there is a need for an enterprise architecture where independent services from various vendors are can be easily deployed and integrated. Secondly, these services are build in a such manner that they can interact via well-defined APIs, but need no direct access to other services. Finally, techniques that support systematic, rapid development and deployment are needed.

Constant Software Updates vs. Public Software Acquisition

“…Examples are many. Modularity allows changing internals of a module without harming other modules that rely on its services (Parnas, 1972). Inheritance enables making new variants of a baseline module that differ from the baseline a bit or combine things that go hand in hand in design (Taivalsaari, 1996).…”

“…Instead of acquiring one, massive system that is completely managed by the vendor that delivering it, it is possible to decompose the needs to a collection of subsystems, each consisting of functions of meaningful size. These subsystems can be regarded as macroservices (Setälä et al, 2021), in analogy to microservices mentioned above. However, while microservices are the smallest meaningful operational units in the implementation sense, macroservices are the smallest meaningful software systems to be tendered and subcontracted.…”