Algorithms Microservices Spring Boot Application

This project is a test bed for microservices applications running on the latest technologies around Java + Spring + Containers.

Keys focus

1. all microservices
2. all containerized
3. latest versions
4. multiple databases
5. code coverage > 90%
6. clear code
7. build always passing
8. always a work in progress

Techs

• Java 11
• Spring Boot 2.1.0
• Spring Web (using tomcat at moment, thinking about moving to undertow -because of that)
• Spring Cloud (eureka, zuul, etc.)
• Spring DevTool / Actuator (for speeding up the development/restart, etc)
• Spring Admin (for monitoring)
• Spring Security / Oauth2 (for authentication)
• Lombok (for avoiding boilerplate code)
• Swagger-ui / OpenApi (for exposing the rest services in an easy/user-friendly web page)
• Log4j2 (for logging)
• jUnit5 (for testing)
• Docker (generate docker image for the microservices, run the application, etc)
• Kubernetes (run in a k8s cluster)
• MongoDB
• Mysql
• Postgresql

Subject

For avoiding having a poor example of data, the subject of the microservices will be around Algorithms and Data Structures. So, the microservices will implement a few of the basic algorithms (search, sorting, common problems, etc.). I'm using the book Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne, as a base for the algorithms and data structures.

Implementation Notes

1. I know that most of the implementation of the algorithms could be done in static methods, utility classes, etc. However, I will use spring services just to show how that works.
2. I could copy and paste the code from the book and use them. But I will be testing myself to create them and code them in a way which they will be easier to understand (code style, comments, etc).

Code Structure / Subprojects

For making things easier, all microservices projects are subproject/modules from this maven project. That will make things easier than have separated git repositories for each one.

I've also added some module prefix for a better understanding:

• ms- : for microservices
• lib- : for library/jar
• server- : for servers
• app-: for app gateway

Subprojects

app-algorithms > Subproject for the app gateway microservice project.

lib-core > Subproject with few reusable codes for the microservices implementation. Just a library.

lib-data-structures > Subproject with data structures implementation. Just a library.

ms-problems-service > Subproject for the problems microservice.

ms-searching-service > Subproject for the searching microservice.

ms-sorting-service > Subproject for the sorting microservice.

server-admin > Subproject for the server admin.

server-eureka > Subproject for the service discovery - eureka server/service.

See it running

The apps are deployed as containers on the cloud. Please feel free to test it.

Eureka Server:

Admin Server:

App Algorithms:

Searching Service:

Sorting Service:

Problems Service:

Running

Option A)

The faster way, running using the docker images that the last successful build generated.

Step 1) Download the file docker-compose.yml

Step 2) Open a terminal/powershell, go to the directory of the docker-compose.yml file and run:

docker-compose up

It should start up all the services. That is it. Play around and have fun! :)

Option B)

Getting the code and compiling and running it.

Step 1) Clone the code

Step 2) Open a terminal/powershell, go to project root directory and run maven to generate the jars

.\mvnw install docker:build -D maven.test.skip=true

Note: skipping the testing for speeding up

Step 3) Run docker compose to start up all the services

docker-compose up