Challenge description

You are required to write a web API with 2 endpoints:

A “Set timer” endpoint.
- Receives a JSON containing hours, minutes, seconds and web url
- This endpoint should return a JSON with a single field - “id"
- This endpoint should define an internal timer, which shoots a webhook to the defined URL after the time ends (a POST HTTP call with an empty body)
- For example:

POST /timers {hours: 4, minutes: 0, seconds: 1, url:"https://someserver.com"}

should return

{id: 1}

After 4 hours and 1 second, server should call

POST https://someserver.com/1

The counter id should be appended to the URL, i.e.: https://someserver.com/:counter_id

A “Get timer status” endpoint
- Receives timer id in the URL, as the resource id
- Returns a JSON with the amount of seconds left until the timer expires. If timer already expired, returns “0”
- For example:

GET /timers/1

Should return

   {id: 1, time_left: 645}

The timers should persist.
If we shut down the process and restart it, timers should be saved.
If a timer should have fired when the server was down, the server should fire the web hook after initializing.

Notes:

Please use Python/ Javascript / Typescript / Java or C#.
Please add a readme with clear execution instructions (solution will be tested in macos environment).
If you’re using another language, please package accordingly so we could install and run it with minimum friction (ie packed in docker).
Solutions will be measured by code structure and by their ability to handle large scale (large number of timers).
Feel free to add any extra functionality you wish.
You’re welcome to approach me for any questions you may have.