Density Fullstack Homework Assignment

Goal

Your goal is to build a web application that displays the latest "heartbeat" from a number of sensors.

Assignment

Your task is to accomplish the following:

• Use Django (or some similar Python web framework) to build a web application
• Scaffold a database that includes sensors and heartbeats
  • A sensor is a device in the field. It generally includes a serial number and other metadata
  • A heartbeat is a periodic message used to tell the backend that the sensor is online and provide the current state of the sensor
  • It is left as an exercise to the candidate to define exactly what data is stored (as well as how it is stored) for a sensor and a heartbeat
• Expose an endpoint that can receive "heartbeats" indicating that the sensor is alive and checking in
• Deliver a webpage where a user can view live, updating heartbeats from the sensors.
• Deliver a script that can emulate one or many sensors by sending emulated heartbeats to the "heartbeats" endpoint.

Bonus Points: Build or tell us how you would include a way to alert users if a sensor hasn’t sent a heartbeat in the last 10 minutes.

IoT Fullstack Position

If you are applying for the IoT fullstack position, please follow the assignment above with the following modifications:

• The sensor emulation script should be written in modern C++ using libcurl.
• It is not required to use a front-end framework such as react for the UI. Viewing live heartbeats can be server side rendered HTML tables or whatever is simplest for you. A page refresh is perfectly acceptable to view updates of live heartbeats. We do not expect ajax or websockets to be used.

Backend Only Position

If you are applying for a backend only position, please follow the assignment above with the following modifications:

• It is not required to use a front-end framework such as react for the UI. Viewing live heartbeats can be server side rendered HTML tables or whatever is simplest for you. A page refresh is perfectly acceptable to view updates of live heartbeats. We do not expect ajax or websockets to be used.

Don't Let the Dog Eat Your Homework

Our goal is to understand your thought process, documentation style, and to get a sense of how you reason about a complex system. Please don't spend more than 3-4 hours on this. We'd prefer incomplete work with notes on what you focused on, where you left off, and the limitations of your solution.

If you get stuck or need more information, don't hesitate to reach out for clarity!