EdsonF / cqrs-example

CQRS: Command Query Responsibility Segregation - Node.js at Scale

cqrs-example

CQRS with Denormalizer example repo for the Node.js at Scale blog series

Requirements

• Node.js
• RabbitMQ: brew install rabbitmq

Usage

npm start

In this example you can see how an imaginary user service emits change events. A denormalizer listens for these change events and stores a subset of the user (name only) in a Reporting Database for further client queries.

Because of eventually consistency the Reporting Database is may out of sync.

Inputs

Create user:  { name: 'John Doe', state: 'default' }
Update user's state:  { state: 'churn' }
Rename user:  { name: 'John Smith' }

Output

Running...
User in user service database { id: 'aaa', name: 'John Smith', state: 'churn' }
User in Reporting Database { name: 'John Smith' }