Waiting machine is an application that enables the management of people waiting in line to ride the train. This is a demo application for Grafana and Prometheus presentation (ex. JavaCro 22).

Implemented features are:

• Queue management: add a user to queue and fetch all users that are currently in queue
• Report endpoint for managers: this endpoint will either return success or an error
• Entrance scheduler: dummy counter of people who entered amusement park
• Queue scheduler which will put people to ride
• Overcrowded scheduler that checks if there is an overcrowded queue

Waiting machine is written in Java using Spring Boot framework.

Running the project will require both Java and Docker (docker-compose) installed on the system:

• Java/JDK 17+
• Docker and docker compose

Run Docker compose command to start PostgreSQL database, Prometheus server and Grafana application:

docker-compose up

To start Waiting machine server, run Maven wrapper command which will build everything and serve web application on localhost:8080

./mvnw spring-boot:run

In this project there is Postman collection file: WaitingMachine.postman_collection.json. You can use it for playing with backend endpoints.

Health check is implemented using Spring Actuator and exposed on actuator/health endpoint:

http://localhost:8080/actuator/health

Also, project is packed with Grafana and Prometheus monitoring tools. Both technologies are run from docker-compose and already set-up for the project.

Prometheus can be accessed from: http://localhost:19090

Grafana can be accessed from: http://localhost:13000 with username admin and password admin.