Characterization of bottom-up microservice composition evolution. An approach based on the choreography of BPMN fragments

Abstract

[EN] Microservices need to be composed in order to provide their customers with valuable services. To do so, event-based choreographies are used many times since they help to maintain a lower coupling among microservices. However, this solution rises the composition complexity since the control flow is distributed across microservices and it is difficult to analyze and understand the big picture of it. To improve this problem, a previous work presented an approach that proposed creating the big picture of a composition in a BPMN model, splitting it into BPMN fragments, and distributing these fragments among microservices. A tool-supported architecture was also proposed to achieve that both descriptions of a composition (the big picture and the split one) coexist in a system. In the current work, we present a first step to face the problem of evolving microservice compositions that are created and deployed with our approach. To do so, we need to consider that we can evolve a microservice composition from (1) its big picture (top-down approach) and (2) a particular BPMN fragment (bottom-up approach). We pay special attention to the bottom-up approach and present a characterization of the changes that can be done, analyze the impact that each of them has on the global composition, and propose compensation actions that maintain the integrity of the composition when possible.