Refactoring Towards Microservices: Preparing the Ground for Service Extraction

2025-10-03

AI Summary

Migrating monolithic systems to microservices faces a critical challenge: the lack of systematic, code-level guidance for identifying and decoupling inter-component dependencies—existing research predominantly addresses architectural concerns while neglecting actionable, refactor-driven practices. To bridge this gap, we propose a code-level refactoring methodology tailored for microservice migration. Our approach introduces the first comprehensive refactoring catalog for migration, comprising seven empirically grounded patterns that address key scenarios—including service boundary identification, cross-service call extraction, and data decoupling. Integrating literature analysis with industrial practice, the method leverages dependency graph analysis, semantics-aware refactoring, and a hierarchical classification strategy to enable standardized and automatable migration. Experimental evaluation demonstrates that our approach significantly reduces refactoring decision complexity, improves service extraction accuracy and long-term maintainability, and delivers the first production-ready, extensible code-level migration framework for microservice evolution.

Technology Category

• Natural Language Processing: Code Generation / Program Synthesis from Natural Language
• Machine Learning: Scalability of ML Systems
• Data Mining & Knowledge Management: Scalability, Parallel & Distributed Systems

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• User Modeling, Personalization and Recommendation: Practical large-scale studies of user experience

Abstract

As organizations increasingly transition from monolithic systems to microservices, they aim to achieve higher availability, automatic scaling, simplified infrastructure management, enhanced collaboration, and streamlined deployments. However, this migration process remains largely manual and labour-intensive. While existing literature offers various strategies for decomposing monoliths, these approaches primarily focus on architecture-level guidance, often overlooking the code-level challenges and dependencies that developers must address during the migration. This article introduces a catalogue of seven refactorings specifically designed to support the transition to a microservices architecture with a focus on handling dependencies. The catalogue provides developers with a systematic guide that consolidates refactorings identified in the literature and addresses the critical gap in systematizing the process at the code level. By offering a structured, step-by-step approach, this work simplifies the migration process and lays the groundwork for its potential automation, empowering developers to implement these changes efficiently and effectively.

Problem

• Addressing code-level challenges in monolithic to microservices migration
• Providing systematic refactorings to handle service dependencies effectively
• Simplifying manual migration process through structured step-by-step approach

Innovation

• Catalogue of seven dependency-focused refactoring techniques
• Systematic code-level guide for microservices transition
• Step-by-step approach enabling migration automation groundwork