Supporting a Hybrid Composition of Microservices. The EUCalipTool Platform

[EN] To provide complex and elaborated functionalities, Microservices may cooperate with each other either by following a centralized (orchestration) or decentralized (choreography) approach. It seems that the decentralized nature of microservices makes the choreography approach more appropriate to achieve such cooperation, where lighter solutions based on events and message queues are used. However, orchestration through the usage of a process model facilitates the analysis of the composition when this is modified. To benefit from the goodness of these two approaches, this paper presents a hybrid solution based on the choreography of business process pieces that are obtained from a previously defined description of the complete microservice composition. To support this solution, the EUCalipTool platform is presented.This work has been developed with the financial support of the Spanish State Research Agency under the project TIN2017-84094-R and co-financed with ERDF.Valderas, P.; Torres Bosch, MV.; Pelechano Ferragud, V. (2020). Supporting a Hybrid Composition of Microservices. The EUCalipTool Platform. Journal of Software Engineering Research and Development. 8(1):1-14. https://doi.org/10.5753/jserd.2020.457S1148

Measuring the modeling complexity of microservice choreography and orchestration: The case of e-commerce applications

Context: 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 needs. Hence, this research uses existing complexity metrics from the software engineering and business process modeling domains on small, mid-sized, and end-to-end e-commerce scenarios to analyze and compare the level of complexity of microservice Orchestration and Choreography using Business Process Modeling Notation (BPMN). Objective: Comparing 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. Method: This research follows a five-step process for conducting a Design Science Research (DSR) methodology to define, develop and evaluate BPMN-based models for microservice compositions. Results: A series of BPMN workflows are designed as artifacts to investigate microservice Choreography and Orchestration. The results derived from the complexity evaluation of our proposed models show a higher level of complexity in orchestrating microservices for e-commerce applications given the number of services used in modeling Orchestration compared to Choreography. Conclusion: This research uncovers insights on modeling microservice Choreography and Orchestration and discusses the impacts of complexity on the modifiability and understandability of the proposed models. Keywords: Microservice, Microservice Composition, Choreography, Orchestration, Complexity Metric, BPMN