Project Introduction: Bounded Context Canvas
Overview
The Bounded Context Canvas is a strategic tool designed for collaborative use in designing and documenting the architecture of a single bounded context. Bounded contexts are essential in Domain-Driven Design (DDD), helping teams clearly define and separate domains within complex systems. For those unfamiliar with the concept, additional reading is available from Eric Evans’s DDD Reference and Martin Fowler’s article on Bounded Contexts.
The canvas serves as a guide through the workflow of designing a context by prompting decisions on naming conventions, responsibilities, public interfaces, and dependencies. It provides a structured approach to ensure comprehensive coverage of critical design aspects, which may otherwise be overlooked.
Purpose and Usage
- Purpose: The canvas helps articulate the purpose of each context and its relevance from a business perspective. This includes identifying core areas that are crucial for strategic initiatives, thus fostering a shared understanding among team members.
- How to Use: Users should begin with the name and purpose of the context and then proceed through other sections, such as inbound communication and business decisions. The sequential approach aligns the team’s thinking and prioritizes the capture of essential elements.
Key Sections
Naming and Purpose
Creating consensus on the context's name is a fundamental step, as it sets the tone for the entire design process. The purpose outlines the 'why' and 'what' without delving into technical details, ensuring clarity and alignment within the team.
Strategic Classification and Domain Roles
This section helps evaluate the context's strategic importance by classifying it as a core, supporting, or generic domain. It also examines the context's role in the business model, such as being a revenue generator or a compliance enforcer.
Communication and Language
Inbound and outbound communication sections involve how the bounded context interacts via messages and collaborations with other contexts. The ubiquitous language section defines key domain terms, promoting a shared vocabulary that reduces misunderstandings.
Business Decisions and Assumptions
Understanding key business rules and assumptions is critical. These sections ensure that decisions are informed by clear business logic and that underlying assumptions are acknowledged to mitigate risks.
Tools and Resources
Several tools are available to assist with the Bounded Context Canvas:
- HTML and Miro Versions: Online templates are available to facilitate collaborative editing.
- draw.io and Excalidraw Versions: These provide graphical interfaces to visualize and adapt the canvas.
Design Tips
The canvas enables visibility of a design, allowing teams to iteratively improve their understanding and implementation. Some tips include testing the effect of moving elements between contexts and ensuring that the public interface is well-designed, with coherent and optimally sized message types.
Conclusion
The Bounded Context Canvas is a vital resource for those engaged in Domain-Driven Design. Its structured approach, varied tools, and helpful tips foster a collaborative environment aimed at robust context design and stakeholder alignment. This canvas ensures not only effective design but also a way to adapt and evolve designs as teams grow their understanding of complex systems.