README.md

REST API service for the Change Machine

API specification

$ make run-local
poetry run uvicorn change_machine_service.api:app --reload
INFO:     Will watch for changes in these directories: ['/Users/a.yushkovskiy/gh/atemate/case-change-machine']
INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:     Started reloader process [34193] using WatchFiles
INFO:     Started server process [34197]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
...

$ curl 'localhost:8000/api/v1/pay?eur_inserted=10&product_price_eur=4.9' | jq
{
  "total_coins": 4,
  "total_eur": 5.1,
  "coins": [
    {
      "count": 2,
      "value": 2,
      "value_in_cents": 200,
      "name": "euro",
      "type": "coin"
    },
    {
      "count": 1,
      "value": 1,
      "value_in_cents": 100,
      "name": "euro",
      "type": "coin"
    },
    {
      "count": 1,
      "value": 10,
      "value_in_cents": 10,
      "name": "cent",
      "type": "coin"
    }
  ]
}

For more complete API specification please check http://127.0.0.1:8000/api/v1/docs

Configuration

See src/chg-service/change_machine_service/settings.py, which can be overloaded using environment variables with the server restart. For example:

• specify the change-computation algorithm: export CHG_ALGORITHM="greedy_search"
• specify log file path (defaults to none): export SRV_LOG_FILE="/path/to/log.ndjson"

Load testing

Reports not recorded, but when tested in local docker, the server holds ~300 rps with latency ~50 ms: