mark-dudu / microservices-hello-world

'Hello World' Application with Spring Boot Microservice Stack

'Hello World' Application with Spring Boot Microservice Stack

This is simple microservice application designed to illustrate the basic concept of Microservice Architecture and to provide a starting point for future development of any business application.

Requirements

This microservice application produces a 'Hello World' messages in JSON format. The second part of the message is replaceable and configurable based on a value in the property file. For example, if the property file is updated and the word 'World ' is replaced with 'Java', the service starts producing 'Hello Java' message.

Solution

The business logic is located in two Microservices:

Microservice Name	Location	Description
HelloWorld Service	/helloworld_service	The main service. It receives client requests, calls GetName service to get the second part of the greeting message, builds the whole message and returns it to the client in JSON format. Note: A Circuit Breaker is used in the GetName call.
GetName Service	/getname_service	Provides the second part of the 'Hello World' message from /config_dir/getname-service.properties file.

This implementation is based on Spring Boot v2.2.2 and Spring Cloud Netflix frameworks.

Deployment

There are several ways to deploy these microservices. The easiest way is to run them on a local machine as normal Java applications.

Here is preferable order to start these microservices with user interface or endpoint URLs:

Microservice Name	Location	Access URL	Description
Discovery Service (Eureka)	/eureka_service	http://localhost:8761/	Provides registration, discovery and load balancing functionality for the other microservices.
Config Service	/config_service	N/A	Provides microservices with externalized configuration information.
Admin Service	/admin_service	http://localhost:8080/	Provides a user interface for for managing and monitoring all microservices within the stack.
GetName Service	/getname_service	http://localhost:8887/	Functional microservice. Retrieves the second part of the 'Hello World' message.
HelloWorld Service	/helloworld_service	http://localhost:8886/	The main functional microservice. Produces a 'Hello World' messages in JSON format. This endpoint URL is accessible from within the microservices stack.
Gateway Service	/gateway_service	http://localhost:9000/	Provides an access to HelloWorld Service endpoint from outside of microservices stack. Usually, for security reason the only open port in the firewall is the port of the Gateway Service.