This application can be run using the docker-compose file. Copy the file named, plc-code-challenge-compose.yml file, and it will automatically pull the dependent images (redis, zookeeper and apache kafka) and run all containers. The following command needs to run

docker-compose -f plc-code-challenge-compose.yml up

Now from the browser, check the Swagger-UI for api docs. Also browse the H2-db-console. User can register from the /register api and use his credential to generate JWT token from /authenticate api in AuthenticationController. For testing purpose an user will be automatically created with following credential.

username: test

password: 123

Database credential:

username: root

password: root123

JWT Token sample:

Bearer eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJ0ZXN0IiwiZXhwIjoxNjkzMDg3NDc0LCJpYXQiOjE2OTMwNjk0NzR9.cQ3a55lKfd4UjzmIiZ9JSzvJ5Y-leVCbx4zs6lHjlf8Ft8wZ9oBDONWZ0_y0jxl-rXqICSAJM7r6iWvLbYhguw

This application is built using Spring Boot 2.7 and Maven is used as build tool. Following dependencies are added in this module

• spring-boot-starter-web
• swagger2
• spring-boot-starter-security
• jwt
• spring-boot-starter-cache
• spring-boot-starter-data-redis
• spring-kafka
• h2 database

Asynchronous execution is used to handle a large number of battery registrations concurrently.

@Async
@Override
public void saveRequest(BatterySaveRequest model){
    ...
    }

and the asycronous configuration is maintained seperately in AsyncConfig class. For this demo application 2 core with maximum 2 pool size is used.

This application is developed by implement JWT-based authentication and authorization for the API. This token will work on top of spring security and everytime used needs to authenticate and use the token as Bearer in subsequent api request.

Redis cache server is used to improve the query performance.

This application used apacke kafka for producing and consuming the message. Once the battery capacity will update, a message will be sent to kafka server and in this module a listener is added to listen the message. Spring default configuration is used for kakfa streaming.

@KafkaListener(topics = Constants.TOPIC_NAME, groupId = Constants.GROUP_ID)
void listeningCapacityUpdate(String message){
    logger.info("Capacity update listening.");
    ...
    }

This version control of this project is maintained gitlab and a CI/CD pipeline is used to test, build and deploy a image to gitlab registry. From this registry user can pull the image and run the containers. A docker-compose file is developed to run as standalone and added in this project folder.

Swagger2 is used to generate the REST API documents for RESTful web services.

Multiple test case are added in this project.