Measuring the Modeling Complexity of Microservice Choreography and Orchestration: The Case of E-commerce Applications

Abstract

With the increasing popularity of microservices for software application development, businesses are migrating from monolithic approaches towards more scalable and independently deployable applications using microservice architectures. Each microservice is designed to perform one single task. However, these microservices need to be composed together to communicate and deliver complex system functionalities. There are two major approaches to compose microservices, namely choreography and orchestration. Microservice compositions are mainly built around business functionalities, therefore businesses need to choose the right composition style that best serves their business needs.

In this research, we follow a five-step process for conducting a Design Science Research (DSR) methodology to define, develop and evaluate BPMN-based models for microservice compositions. We design a series of BPMN workflows as the artifacts to investigate choreography and orchestration of microservices.

The objective of this research is to compare the complexity of the two leading composition techniques on small, mid-sized, and end-to-end e-commerce scenarios, using complexity metrics from the software engineering and business process literature. More specifically, we use the metrics to assess the complexity of BPMN-based models representing the abovementioned e-commerce scenarios.

An important aspect of our research is the fact that we model, deploy, and run our scenarios to make sure we are assessing the modeling complexity of realistic applications. For that, we rely on Zeebe Modeler and CAMUNDA workflow engine.

Finally, we use the results of our complexity assessment to uncover insights on modeling microservice choreography and orchestration and discuss the impacts of complexity on the modifiability and understandability of the proposed models.