Intro to Pattern :: CQRS

Hi guys, in this project that use how to example for see CQRS pattern, I create two microservices where one has a function how to Command, and other how to Query.

NOTA: This project no use many other aspect to consider, such as security, concurrency, data consistence, on so on.

This project is only how to testing. CQRS is a pattern help us separate own system in write and read, but their precise implementation depend on the complexity and specific requirements of the system.

the Project

This project has two microservices, where one is a Command, and other the Query. Each has own database. To synchronize the database, the microservices use the Kafka broker.

Microservice Command

In this service, the system add/edit contact in our DB. Here set to the system how to producer one message to Kafka.

Microservice Query

In this service, the system read the DB. Here set the system how to consumer of kafka.

Resources for use this example

Note: when execute docker cmd, make sure to start Docker Desktop.

For execute resource of database and Kafka environment, can be use to docker compose files:

# For create MySql database
docker-compose -f dc-mysql-container.yml up --build -d

# for create Kafka broker
docker-compose -f dc-kafka-container.yml up --build -d
 
# after started, we can see its health in cmd
docker ps

stop container

For stop all container the use in in this tutorial, can be type in CMD:

# for see our containers, where I get the names of container
docker ps

# for stop, use name of container listing in previous step.
docker stop <name-container-1> 
docker stop <name-container-2> 
#...on so on

# after it, for see if container is stopped
docker ps
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES