A Domain-Driven Design Simulator for Business Logic-Rich Microservice Systems

TL;DR

This paper introduces a Domain-Driven Design microservice simulator that enables early validation and testing of business logic under various consistency models and deployment topologies, reducing development effort.

Contribution

It presents a novel simulator that isolates core business logic from infrastructure, supporting multiple transactional models and deployment scenarios for microservices.

Findings

The simulator effectively models complex microservice systems with multiple aggregates.

Empirical benchmarks show performance and resilience differences across transactional models.

The approach reduces developer effort in validating business logic early in development.

Abstract

Developing business-logic-rich microservices requires navigating complex trade-offs between data consistency and distributed coordination. Although patterns like Sagas and Transactional Causal Consistency (TCC) provide mechanisms to manage distributed state, validating their behavior before production is challenging. Current architectural simulators prioritize network metrics over domain semantics, whereas industry frameworks demand full-scale infrastructure deployments, preventing early architectural experimentation. To bridge this gap, we introduce a \textit{Domain-Driven Design} (DDD) microservice simulator that isolates core business logic from communication and transactional infrastructure. By modeling microservice systems around aggregates, the simulator allows developers to evaluate identical application code under varying consistency guarantees and network constraints. It features support for multiple transactional models (Sagas, TCC) and seamless transitions across diverse deployment topologies, ranging from centralized execution to fully distributed environments. We validate the simulator through the implementation and rigorous concurrency testing of a complex, multi-aggregate microservice system. Through empirical benchmarks, we quantify the performance, coordination overhead, and resilience of different transactional models across localized and distributed execution environments. The findings confirm that the simulator minimizes developer effort while providing a powerful, deterministic environment for the shift-left validation and optimization of business logic implementation in microservice architectures.