Decomposite patterns

Question 1

Decomposition patterns

Answer 1

Decompose by business capability

Decompose by subdomain

Question 2

Decompose by business capability: context

Answer 2

You are developing a large, complex application and want to use the microservice architecture.

Question 3

Decompose by business capability: problem

Answer 3

How to decompose an application into services?

Question 4

Decompose by business capability: forces

Answer 4

The architecture must be stable
Services must be cohesive
Services must conform to the Common Closure Principle
Services must be loosely coupled
A service should be testable
Each service be small enough to be developed by a “two pizza” team
Each team that owns one or more services must be autonomous.

Question 5

Decompose by business capability: solution

Answer 5

Define services corresponding to business capabilities.
* It is something that a business does in order to generate value
A business capability often corresponds to a business object, e.g.
Business capabilities are often organized into a multi-level hierarchy. For example, an enterprise application might have top-level categories such as Product/Service development, Product/Service delivery, Demand generation, etc.

Question 6

Decompose by business capability: example

Answer 6

The business capabilities of an online store include:
* Product catalog management
* Inventory management
* Order management
* Delivery management
…

Question 7

Decompose by business capability: result

Answer 7

Stable architecture since the business capabilities are relatively stable
Development teams are cross-functional, autonomous, and organized around delivering business value rather than technical features
Services are cohesive and loosely coupled

Question 8

Decompose by business capability: issues

Answer 8

How to identify business capabilities?
Good starting points for identifying business capabilities are:
organization structure - different groups within an organization might correspond to business capabilities or business capability groups.
high-level domain model - business capabilities often correspond to domain objects

Question 9

Decompose by business capability: related patterns

Answer 9

The Decompose by subdomain pattern is an alternative pattern

Question 10

Decompose by business subdomain: context

Answer 10

You are developing a large, complex application and want to use the microservice architecture.

Question 11

Decompose by business subdomain: problem

Answer 11

How to decompose an application into services?

Question 12

Decompose by business subdomain: forces

Answer 12

The architecture must be stable
Services must be cohesive
Services must conform to the Common Closure Principle
Services must be loosely coupled
A service should be testable
Each service be small enough to be developed by a “two pizza” team
Each team that owns one or more services must be autonomous.

Question 13

Decompose by business subdomain: solution

Answer 13

Define services corresponding to Domain-Driven Design (DDD) subdomains.
Each subdomain corresponds to a different part of the business.
Subdomains can be classified as follows:
* Core - key differentiator for the business and the most valuable part of the application
* Supporting - related to what the business does but not a differentiator. These can be implemented in-house or outsourced.
* Generic - not specific to the business and are ideally implemented using off the shelf software

Question 14

Decompose by business subdomain: example

Answer 14

The subdomains of an online store include:

• Product catalog
• Inventory management
• Order management
• Delivery management
• …

Question 15

Decompose by business subdomain: result

Answer 15

Stable architecture since the business capabilities are relatively stable
Development teams are cross-functional, autonomous, and organized around delivering business value rather than technical features
Services are cohesive and loosely coupled

Question 16

Decompose by business subdomain: issues

Answer 16

How to identify the subdomains?
Good starting points for identifying subdomains are:
* organization structure - different groups within an organization might correspond to subdomains
* high-level domain model - subdomains often have a key domain object

Question 17

Decompose by business subdomain: related

Answer 17

The Decompose by business capability pattern is an alternative pattern