/test-assignment-ps

Primary LanguageGo

PerfectScale test assignment

Assignment

  1. Learn go

    Write a webserver in Go:

    a. Implement the following Apis:

    • /USER/:USERNAME/URL/*ADDRESS
      • your webserver will download the WEB_ADDRESS http response and respond with number of milliseconds the request took.
      • you should store per use statistics:
        • how many requests for this user?
        • how many requests succeeded/failed?
        • total requests time (per success/fail)
    • /USER/:USERNAME/STATS
      • return statistics - number of successful and failed requests, avg req time.
    • /STATS
      • return statistics like above, ignore USER_NAME dimension (total stats of all users)

    b. add a configurable rate limiter - X requests per minute is allowed

    • please add to user stats also number of throttled (=not allowed) requests

  2. Learn k8s

    • k8s tutorial
    • Deploy any k8s, you can use minikube on your laptop (or k3s, or kind..)
    • helm tutorial
    • create helm for your web server
    • deploy your helm chart on minikube. Note that for high availability, we want at least two running instances of the web server (rate limiter is distinct for every instance)
    • port-forward to your service running on k8s and make sure you can access service APIs (should you port-forward to pod? service?)

  3. Learn Prometheus & Grafana ( we can help a bit here).

    a. deploy prometheus and grafana to your cluster ( https://github.com/prometheus-community/helm-charts/tree/main/charts/kube-prometheus-stack)

    b. Create a grafana dashboard

    • Show how much memory / cpu does your service use.

    c. expose number of success / failed requests per endpoint

    • for this you should instrument your webserver with prometheus metrics
    • add to your helm chart a servicemonitor resource (so prometheus can scrape your custom metrics)
    • add graphs to the grafana dashboard above

Throttler solution X limits per minute

map[userID]counter

  1. if below limit - fire request, otherwise skip and add to throttled
if counter[userID] >= limit { 
	throttled += 1
} else { 
	fire request
	counter[userID] += 1
}
  1. counter = 0 after 1 minute
go func() {
	<-timer.After(1*time.Minute)
	mutex.lock
	defer { mutex.unlock }
	counter[userID] = 0
}()