axiompraxis/borrowanumber

BorrowANumber

Purpose

This was a project where I needed to solve an issue with multiple load performance tests simultaneously (using k6), the test users were experiencing collisions with usernames.

Rather than work out complex logic to have them determine which user number they were, I created this small development server to resolve it, all it does is serve up numbers for them. They borrow a number, and when they're done, they return it for another load test user.

Reminder this is just an example and no guarantees are provided. A Production grade WSGI server like gunicorn would be recommended over this basic flask example.

Example Linux Installation

1. Install Python
2. Install Redis Cluster (I used redis-cluster helm chart from bitnami) and telepresence on a k3s cluster, but regular redis-cluster works fine too.
3. (Optional) - setup virtualenv for your python
4. Install from requirements: pip install -r requirements.txt
5. Create a .env file with your variables:

   REDIS_PASSWORD="secret"
   RANGE_START=10000
   RANGE_AMOUNT=10000

   This example would serve numbers 10000-20000
6. Run the server: python BorrowANumber.py

REST API

The REST API to the example app is described below.

Get list of checked numbers

Request

GET /checked

curl http://localhost:5000/checked

Response headers

Connection: close
Content-Length: 27
Content-Type: application/json
Date: Fri, 01 Mar 2024 00:00:00 GMT
Server: Werkzeug/3.0.1 Python/3.12.0

Response body

{
  "checked_out_numbers": []
}

Check out a new number

Request

GET /check

curl http://localhost:5000/check

Response headers

HTTP/1.1 200 OK
Connection: close
Content-Length: 31
Content-Type: application/json
Date: Fri, 01 Mar 2024 00:00:00 GMT
Server: Werkzeug/3.0.1 Python/3.12.0

Response body

{
    "checked_out_number": "16713"
}

Return a number

Request

POST /return

curl -H "Content-Type: application/json" -XPOST http://localhost:5000/return

Response headers

HTTP/1.1 200 OK
Connection: close
Content-Length: 49
Content-Type: application/json
Date: Fri, 01 Mar 2024 00:00:00 GMT
Server: Werkzeug/3.0.1 Python/3.12.0

Response body

{
  "message": "Number 16713 returned successfully"
}

Reset all numbers

Request

GET /reset

curl http://localhost:5000/reset

Response headers

HTTP/1.1 200 OK
Connection: close
Content-Length: 17
Content-Type: application/json
Date: Fri, 01 Mar 2024 00:00:00 GMT
Server: Werkzeug/3.0.1 Python/3.12.0

Response body

{
  "reset": "true"
}