Doing microservices with JHipster

Today many companies are developing applications using Microservices, and Microservices with spring boot is chosen by many big companies in Vietnam.
In JHipster framework, Microservices is also supported. JHipster is a free and open-source application generator used to quickly develop modern web applications and Microservices using Angular or React (JavaScript library) and the Spring Framework.

Some technologies and tools are:

• Yeoman, a front-end scaffolding tool
• Spring Boot
• Angular 8, ReactJS: frontend Javascript frameworks.
• Swagger, for API documentation
• Maven, Npm, Yarn, Gulp and Bower are dependency managers and build tools
• Jasmine, Protractor, Cucumber and Gatling are test frameworks
• Liquibase is for database versioning

We need to  install Java 8, Git (version control system), NodeJS, Yeoman, Yarn and may be Gulp and Bower also on the computer.

Microservices vs Monolithic architecture

The first question JHipster will ask you is the kind of application you want to generate. You have the choice between two architecture styles:

• A “monolithic” architecture uses a single, one-size-fits-all application, which contains both the front-end code, and the back-end Spring Boot code.
• A “microservices” architecture splits the front-end and the back-end, so that it’s easier for your application to scale and survive infrastructure issues.

A “monolithic” application is much easier to work on, so if you don’t have any specific requirements, this is the option we recommend, and our default option.
However, A “monolithic” application is still an Spring Boot application with Microservices support.

Microservices architecture overview

The JHipster microservices architecture works in the following way:

• A gateway is a JHipster-generated application (using application type microservice gateway when you generate it) that handles Web traffic, and serves an Angular/React application. There can be several different gateways, if you want to follow the Backends for Frontends pattern, but that’s not mandatory.
• Traefik is a modern HTTP reverse proxy and load balancer that can work with a gateway.
• The JHipster Registry is a runtime application on which all applications registers and get their configuration from. It also provides runtime monitoring dashboards.
• Consul is a service discovery service, as well as a key/value store. It can be used as an alternative to the JHipster Registry.
• JHipster UAA is a JHipster-based User Authentication and Authorization system, which uses the OAuth2 protocol.
• Microservices are JHipster-generated applications (using application type microservice application when you generate them), that handle REST requests. They are stateless, and several instances of them can be launched in parallel to handle heavy loads.
• The JHipster Console is a monitoring & alerting console, based on the ELK stack.

In the diagram below, the green components are specific to your application and the blue components provide its underlying infrastructure.

From above picture, we can see that Eureka Server has been wrapped into Jhipster Registry, because the standard architecture of Eureka Server is something like following:

Docker installation

Guide to install docker on windows: https://docs.docker.com/toolbox/toolbox_install_windows/, https://github.com/docker/toolbox/releases
After installation, click on shortcut on desktop of computer to start docker

Then the terminal will appear with messages

Type the docker run hello-world command and press RETURN.

In the first times, It will show errors and then download hello-world example. If you run that command in the second times, It will show above messages. That means the installation of docker is okay.

Install Compose on Windows desktop systems
Docker Desktop for Windows and Docker Toolbox already include Compose along with other Docker apps, so most Windows users do not need to install Compose separately. Docker install instructions for these are here:

• Get Docker Desktop for Windows
• Get Docker Toolbox (for older systems)

Links:
https://www.jhipster.tech/microservices-architecture/
https://spring.io/blog/2015/07/14/microservices-with-spring

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