Phoenix Games Publishing Platform Backend Developer Trial Task

Our top individual contributor Gabriel Schweinsteinburgberger recently started to develop a new service called User Profile API. Unfortunately for us, Gabriel got spontaneously married during his spiritual journey to Tibet. He decided to give up developing software in favor of running a mountain goats farm with his newly wedded wife. A lot of changes for the good for Gabriel, but we still have to deliver the project on time without his valuable contributions.

Project domain

The idea of the User Profile API is to accept commands from various sources and update the user profile according to them. The user profile is a collection of properties associated with the userId. User profiles can be created on the fly when user is first time seen by the service.

User Profile API was born to live to decouple operations on the user profile and its storage from the logic responsible for extracting the data from the outside world.

We foresee the following command types needed from the start and more types added in the future:

replace to replace the value of a certain property of the user profile.

{
  "userId": "de4310e5-b139-441a-99db-77c9c4a5fada",
  "type": "replace",
  "properties": {
    "currentGold": 500,
    "currentGems": 800
  }
}

increment increments the current value in the profile. This command can also take negative numbers to decrement the value.

{
  "userId": "de4310e5-b139-441a-99db-77c9c4a5fada",
  "type": "increment",
  "properties": {
    "battleFought": 10,
    "questsNotCompleted": -1
  }
}

collect adds values to a list of the values in the user profile property:

{
  "userId": "de4310e5-b139-441a-99db-77c9c4a5fada",
  "type": "collect",
  "properties": {
    "inventory": ["sword1", "sword2", "shield1"],
    "tools": ["tool1", "tool2"]
  }
}

Multiple applications generate commands to update the user profile and send them to User Profile API over HTTP. One example of such applications is a streaming application that listens to the stream of user activity events and sent the command when certain criteria are met. For example, for the user property called numberOfLogins, the streaming application can listen to login events and send an increment command to User Profile API when such an event occurs.

Another example is an ETL application which is run periodically and extracts information from the database to populate averagePlayTimePerWeek property by sending replace commands to User Profile API.

What is already done

There is a project which is set up in the following way:

Java 17 LTS (with support for jenv, if it's your thing)
Gradle with Shadow, JaCoCo, and test-logger plugins
Dropwizard
dropwizard-guicey which brings Guice power to Dropwizard
JUnit 5, Mockito, AssertJ and JsonUnit
GitHub action to build, run checks and tests

These parts of the application are already implemented:

General project setup is done
UserResource is able to return the profile of the user.
UserProfileDaoInMemory implements storage of the user profile in memory.
There are examples of fixture usage, integration tests, and mocking.

Your goal

Add the following components:
- Endpoint to accept commands. We also thought about receiving commands in batches.
- Logic to process different command types and update the user profile accordingly.
Design code in a way that will make adding new command types easy.
Maintain a coherent coding style and keep the test coverage level.

You are expected to work in your own Git repository and send us a link to it when you are done. Feel free to commit as often and as granularly as you want, we like to see how the progress was.

Please don't fork this repository (otherwise other candidates will see your code), but use it as a template instead .

In the end, we will print the diff and send it to Gabriel Schweinsteinburgberger via paper mail in a desperate hope that he will decide to come back to software development.

A bit more serious

This is a trial task for a developer position, so the story behind it is a fake.
We provide feedback on the trial task regardless of the result since we think it's the least we can do for the candidates that heavily invested time into the trial task.
Trial task will not be compensated or paid.

How to?

Run tests

./gradlew test

Run checks and tests

./gradlew check

Run application

./gradlew run --args='server'

or without Gradle:

./gradlew build
java -jar ./build/libs/userprofile-api-1.0.0-SNAPSHOT.jar server

How to make a request to a running application

curl http://localhost:8080/users/some-user-id/profile

wyworak/user-profile-api