DDD – Domain-Driven Design

Published on: Jan 02, 2023

DDD: Domain-Driven Design for Microservices Modeling

Even though the Domain-Driven design paradigm existed before microservices, it complements the design. Modeling the appropriate level of granularity for a domain in microservices is complex, and microservices may be either too thin or too fat. 

As a result, in this respect, the DDD offers concepts, methodologies, and patterns that aid in comprehending the business domains’ processes, functions, and rules, which will be transformed into services and logic in the business domain microservices. 

Using Domain Driven design and the development that follows Large, complicated projects that call for the engagement of domain experts to gather their expertise and translate it into product features are where the domain-driven design method will work best. 

With the assistance of subject-matter specialists, the DDD technique enables breaking down domain knowledge and modeling the general understanding before execution. The technical team and the business stakeholders may communicate perfectly by using the appropriate artifacts to define the issue area. 

The DDD terminology, such as Domain, Subdomain, Ubiquities language, Bounded context, Aggregate, Value Objects, and Entities, will be introduced to the team. 

From our experience dealing with domain experts, it is crucial to constantly communicate with specialists familiar with the real-world application of the technology we are developing. Additionally, think of the domain expert as a co-developer because they are familiar with the issue rather than programmers. 

We concentrated on the following guidelines and actions while we worked with domain-driven design: 

  • Pay attention to locating and defining the Domain’s borders. 
  • Concentrate on comprehending the fundamental logic included inside the Domain. 
  • Develop a domain model and test it using actual situations and examples. 
  • Find the areas where the business is cooperating. 

Regarding modeling methodologies, while building models, try to provide the simplest solution to challenges encountered in the actual world. Follow the experts’ first breakdown to comprehend and prevent over-factorizing the discovered business entities. 

Review all the discovered business domains and entities later in the modeling activity, then balance the business entities’ responsibilities equally. They prevent anemic domains and maintain a balance between size and size. Opportunities for responsibility redistribution and restructuring will arise as the system expands. 

When adjusting the microservices boundaries, remember that the advantages of isolating deployments and modifying some system elements without impacting other components are the most powerful features of this design. 

Therefore, it is wise to place the advantages we want to attain in relation to our job. Based on this viewpoint, it is necessary to anticipate which system components will change simultaneously and clarify their roles, distinctions, and interactions. 

It is true that when society and business develop, certain presumptions may come true or change. To preserve the entire system’s balance and maintainability, the team must consider having the support of business owners and the ability to adapt, change, or refactor domains. 

We might highlight that several teams have an upfront collaborative effort for the analysis and design phase when discussing the difficulties and possible problems you can encounter while using DDD for microservices. For DDD to be justified, the advantages must balance the work needed to complete the modeling and design. 

Additionally, during this phase—which has to be streamlined—the technical team and the business specialists will need to work together. Using the Event Storming method is the best answer for this. These sessions include organized dialogue between developers and domain specialists to establish models and constrained contexts or limits. 

The event storming sessions aim to map out the events, instructions, and processes while also identifying the many sub-domains, borders, and events that make up the business entities that will adhere to the data model. 

The technical team also has the chance to ask questions and see any areas where the ideas could overlap. The domain language and the business processes are only now becoming clear.