Service Extraction from Object-Oriented Monolithic Systems: Supporting Incremental Migration

Migrating large monolithic systems to service-based architecture is a complex process, mainly due to the difficulty of extracting reusable functionality from tightly coupled components. To support this, Service Identification techniques have been proposed to decompose monoliths into service candidates. Implementing these service candidates requires significant restructuring efforts. To address this complexity and build confidence in the target architecture, prior research recommends using an incremental migration approach where services are extracted one at a time. However, incremental migration has been poorly explored in the literature and lacks dedicated tool support. Thus, we explore the idea of a tool-assisted service extraction to support incremental migration, where one service is extracted at each increment. This paper first discusses the challenges associated with incremental migration. Then, it presents a model-based extraction approach aimed at automatically extracting functionality as a service. The approach is supported by a tool prototype evaluated on an industrial system and an open-source project. Our results show that our tool can extract standalone services that are successfully invoked by a reduced version of the monolith.