Backend Developer Challenge

Context: If you're seeing this, it means we'd like to see how you would solve a real-world problem. But to be totally clear, we won't be using your code for anything beyond deciding on moving forward in the hiring process.

Request statistics exercise

In this exercise you will build a fully functioning Flask application packaged into a Docker Compose environment.

The Flask app should count every request by URL path and store this metric in Redis. This will form the basis of a component that has a wide range of uses like request limiting, capacity planning, cost accounting, etc.

It should handle the following three sets of endpoints:

• GET /api/* - Simulated API endpoints
• GET /stats/ - Returns JSON report of URL request statistics
• POST /test/{number of requests}/ - Starts a test run to generate fake requests

Spec

1. Record number of requests for every URL handled by the Flask application. Data shall be stored in Redis.
2. The /api/* endpoint should handle URL paths starting with /api/ and followed by an arbitrary number of path segments. Example valid URLs: /api/one/ or /api/product/1/. This is used to emulate what would be real API endpoints. For this exercise only consider GET requests but assume there would be millions of unique URLs. Ignore querystrings.
3. The /stats/ endpoint shall return a JSON response that provides the URL request counts ordered from most requested to least requested.
4. /test/{number of requests}/ is a testing endpoint that will simulate real requests:
   1. A POST request will start a test of {number of requests} GET requests to the local web application
   2. Each simulated request uses a random URL composed of:
      1. /api/ followed by 1 to 6 path segments
      2. Each path segment is a random string pulled from a pool of 3 random strings used by a single test run
      3. Example of URLs in a single test run:
         • /api/xyz/ (Valid: 1 path segment, 1 random string used so far)
         • /api/xyz/abc/def/ (Valid: 3 path segments, 3 random strings used so far)
         • /api/xyz/abc/ghi/ (Invalid: 4 different random strings were used for path segments in this test run)
         • /api/xyz/xyz/xyz/xyz/xyz/xyz/xyz/ (Invalid: 7 path segments)
5. Package files into a fully functioning docker-compose project. To test we should be able to unzip files, run docker-compose up and point our local browser to http://localhost:5000/stats/ to get the initial JSON report.

Grading & Submission

Your solution will be evaluated as if it were a pull request for a feature that would serve customers from production infrastructure. It will be graded on functionality, completeness, documentation, cleanliness, production readiness, and code structure. If you are unsure of a requirement just make a reasonable assumption and add a comment in your code.

Create a .zip of your project and include a README containing an overview of your solution with a self-critique explaining what you would continue iterating on if you had more time.