Saulo Soares de Toledo

• Soares De Toledo, Saulo; Martini, Antonio & Sjøberg, Dag (2021). Identifying architectural technical debt, principal, and interest in microservices: A multiple-case study. Journal of Systems and Software.  ISSN 0164-1212.  177 . doi: 10.1016/j.jss.2021.110968 Full text in Research Archive. Show summary

  Background: Using a microservices architecture is a popular strategy for software organizations to deliver value to their customers fast and continuously. However, scientific knowledge on how to manage architectural debt in microservices is scarce. Objectives: In the context of microservices applications, this paper aims to identify architectural technical debts (ATDs), their costs, and their most common solutions. Method: We conducted an exploratory multiple case study by conducting 25 interviews with practitioners working with microservices in seven large companies. Results: We found 16 ATD issues, their negative impact (interest), and common solutions to repay each debt together with the related costs (principal). Two examples of critical ATD issues found were the use of shared databases that, if not properly planned, leads to potential breaks on services every time the database schema changes and bad API designs, which leads to coupling among teams. We identified ATDs occurring in different domains and stages of development and created a map of the relationships among those debts. Conclusion: The findings may guide organizations in developing microservices systems that better manage and avoid architectural debts.

• Soares De Toledo, Saulo; Martini, Antonio & I. K. Sjøberg, Dag (2020). Improving Agility by Managing Shared Libraries in Microservices, In Maria Paasivaara & Philippe Kruchten (ed.),  Lecture Notes in Business Information Processing, vol 396.  Springer Berlin/Heidelberg.  ISBN 978-3-030-58857-1.  Conference proceedings.  s 195 - 202 Full text in Research Archive. Show summary

  Using microservices is a way of supporting an agile architecture. However, if the microservices development is not properly managed, the teams’ development velocity may be affected, reducing agility and increasing architectural technical debt. This paper investigates how to manage the use of shared libraries in microservices to improve agility during development. We interviewed practitioners from four large international companies involved in microservices projects to identify problems when using shared libraries. Our results show that the participating companies had issues with shared libraries as follows: coupling among teams, delays on fixes due to overhead on libraries development teams, and need to maintain many versions of the libraries. Our results highlight that the use of shared libraries may hinder agility on microservices. Thus, their use should be restricted to situations where shared libraries cannot be replaced by a microservice and the costs of replicating the code on each service is very high.

• Soares De Toledo, Saulo; Martini, Antonio; Przybyszewska, Agata & Sjøberg, Dag (2019). Architectural Technical Debt in Microservices: A Case Study in a Large Company, In Paris Avgeriou & Klaus Schmid (ed.),  Proceedings of the Second International Conference on Technical Debt.  IEEE Press.  ISBN 978-1-7281-3371-3.  kapittel. Full text in Research Archive. Show summary

  Introduction: Software companies aim to achieve continuous delivery to constantly provide value to their customers. A popular strategy is to use microservices architecture. However, such an architecture is also subject to debt, which hinders the continuous delivery process and thus negatively affects the software released to the customers. Objectives: The aim of this study is to identify issues, solutions and risks related to Architecture Technical Debt in microservices. Method: We conducted an exploratory case study of a real life project with about 1000 services in a large, international company. Through qualitative analysis of documents and interviews, we investigated Architecture Technical Debt in the communication layer of a system with microservices architecture. Results: Our main contributions are a list of Architecture Technical Debt issues specific for the communication layer in a system with microservices architecture, as well as their associated negative impact (interest), a solution to repay the debt and the its cost (principal). Among the found Architecture Technical Debt issues were the existence of business logic in the communication layer and a high amount of point-to-point connections between services. The studied solution consists of the implementation of different canonical models specific to different domains, the removal of business logic from the communication layer, and migration from services to use the communication layer correctly. We also contributed with a list of possible risks that can affect the payment of the debt, as lack of funding and inadequate prioritization. Conclusion: We found issues, solutions and possible risks that are specific for microservices architectures not yet encountered in the current literature. Our results may be useful for practitioners that want to avoid or repay Technical Debt in their microservices architecture.

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