Toy Robot Simulator

Introduction

This is a solution for the Toy Robot Simulator challenge for my job application. It is not a production-ready service, many things are simplified and guessed from the challenge description. In normal circumstances these assumptions need to be clarified.

Task

Create a Spring Boot application with a REST interface to simulate a toy robot, with the following functionality on the robot:

• PLACE x,y,facing
• MOVE
• LEFT
• RIGHT
• REPORT

The robot is moving on an empty 5x5 table. Any actions, which would lead the robot to fall off the table, must be prevented.

API documentation

The application is deployed on Heroku and provides a Swagger definition. Swagger UI is available:

https://toy-robot.herokuapp.com/swagger-ui.html

Example calls

A Postman collection is attached for easy access.

Report position

curl -X GET "https://toy-robot.herokuapp.com/robot" -H "accept: application/json"

Place on a position

curl -X PUT "https://toy-robot.herokuapp.com/robot" -H "accept: application/json" -H "Content-Type: application/json" -d "{ \"x\": 2, \"y\": 2, \"direction\": \"NORTH\"}"

Execute a command

curl -X POST "https://toy-robot.herokuapp.com/robot/commands" -H "accept: application/json" -H "Content-Type: application/json" -d "{ \"command\": \"MOVE\"}"

Maintenance

Build

./gradlew clean build

Run

./gradlew bootRun

Design decisions and assumptions

• No bulk operation needs to be supported
• Service is manipulating one and only one robot moving on 5x5 table
• Invalid moves do return HTTP errors and never alter the state of the robot
• No need for persistence
• Because the scope is very limited, classes are not structured in packages

Room for improvements

• User-friendly validation (now: fail at first validation violation)
• Transactional operations
• Monitoring: health and metrics