This post shows how to advance from a set of user stories to OpenAPI specifications to API provider stubs via strategic and tactic DDD. This seven-step journey is partially supported and automated in two open source tools, Context Mapper and Microservice Domain-Specific Language (MDSL) Tools. Background information is available here and here.

Prerequisites: The instructions below assume that you have Context Mapper Version 6 and MDSL Tools Version 5 installed.

Step 1: Elicit Functional Requirement(s)

Write a user story in the Context Mapper DSL (CML), as explained in the Context Mapper documentation:

UserStory PaperArchiving { As a "Researcher" I want to create a "PaperItem" with…

This post points you at valuable templates for documenting software architectures as well as a pattern languages that can support their creation.

Architecture Description Formats

When it comes to documenting software architecture requirements and designs, some of my most frequently visited resources are:

1. The twelve-section arc42 template “takes the pain out of documentation” and is accompanied by many hints.
2. ISO/IEC/IEE 42010:2011, defining what frameworks are and making the case for capturing decision rationale. There is a template to ease the creation of 42010-compliant architecture descriptions[1].
3. OpenUP seems to have lost weight in recent years[2]. But it still is a good place to look…

Aspect-Oriented Programming (AOP), Behavior-Driven Development (BDD), CDD, DDD, EDA… can we cook some more “method and practice soup”?

Background and Context

Story 22 on “Diagram-Driven Design” in Gregor Hohpe’s (highly recommend) “Software Architect Elevator” reminded me that I was one of the pundits that once contributed to an “A-Z list of 26 new development strategies” .

This post is a little more conservative and reminds us of actually existing ones.

Are your Designs “Driven”?

Some “driven” methods and styles (past and present) are:¹

• Attribute-Driven Design (ADD) puts quality attributes first; Version 3.0 also covers architectural decisions about frameworks and technologies.
• Behavior-Driven Development (BDD) complements user stories with…

The Design Practice Repository (DPR) on GitHub compiles proven method elements and other knowledge nuggets for API and (micro-)service design — and more general software architecture work.

Update (December 8, 2020): Story splitting and CRC cards now featured, tutorial enhanced with architecture decision record(s), many elements edited and additional background information provided.

Methods: The Good, The Bad and The Why

Read on if you agree:

We all learn well from mistakes — but do these mistakes have to be our own?

You might be thinking that methods (and patterns) are on the other side of cool in the age of Agile, search engines and online developer communities. Who…

What is important when analyzing and designing software architectures, and what is not? This post proposes 5+2 criteria for the architectural significance of requirements (and other artifacts) and applies them to several examples.

Motivation

Let’s assume it is the first day for you on a project that has been running for a while (for instance, one that modernizes some legacy system); you might be an external consultant that has just been hired, or have switched role and project internally. What to work on first?

As a software engineer with architecture responsibilities, I would like to prioritize technical issues quickly so…

Microservice architectures evolved from previous incarnations of Service-Oriented Architectures (SOAs) to promote agility and elasticity. They are often visualized with hexagons and onions (to emphasize service autonomy):

I see such microservices (defined by seven tenets here) as a contemporary implementation approach for Service-Oriented Architecture (SOA) principles and patterns, emphasizing and benefiting from modern software engineering practices such as domain-driven design, containerization and DevOps.

Please read on if you would like to learn why — or disagree.

Revolution! Stagnation! Evolution!

Three rather different positions can be observed, both online and in print:

1. Microservices as a new architectural style competing with SOA and to be…

This post defines microservices via seven tenets, reverse-engineered from books, articles and blogs. It also recapitulates which Service-Oriented Architecture (SOA) principles and patterns I collected to introduce SOA between 2003 and 2009. Such consolidated definitions are required to analyze the SOA style and microservice-based SOA realizations objectively.

What Is in a Microservice?

My paper “Microservices Tenets: Agile Approach to Service Development and deployment” , published in a scientific journal but also openly available, compares several early definitions and distills seven tenets from them:

It is good to know when the most responsible moment for an architectural decision about a pattern or technology has come. But when can a decision be considered done? This post suggests five criteria to help you decide whether you are ready to move on.

The proposal is inspired by the five SMART criteria used in project and people management (but also when eliciting non-functional quality requirements). Let’s look at them one at a time.

Evidence

You have gained reason to believe that the chosen design (selected pattern, technology, product or open source asset and its configuration, that is) will work…