pocket load tester

http_bench.go

package main

import (
	"github.com/VividCortex/gohistogram"
	"net/http"
	"os"
	"time"
)

func main() {
	h := gohistogram.NewHistogram(10)
	println(os.Args[1])

	concurrencyLimit := 50 // Number of simultaneous jobs.
	limiter := make(chan struct{}, concurrencyLimit)

	start := time.Now()
	slow := int64(0)

	results := make(chan float64, 100)
	go func() {
		for f := range results {
			if f > 1000 {
				slow++
			}
			h.Add(f)
		}
	}()


	for i := 0; i < 10000; i++ {
		limiter <- struct{}{} // Reserve limiter slot.
		go func() {
			defer func() {
				<-limiter // Free limiter slot.
			}()

			start := time.Now()
			req, err := http.NewRequest(http.MethodGet, os.Args[1], nil)
			if err != nil {
				println(err.Error())
			}
			resp, err := http.DefaultClient.Do(req)
			if err != nil {
				println(err.Error())
			} else {
				err = resp.Body.Close()
				if err != nil {
					println(err.Error())
				}
			}
			results <- time.Since(start).Seconds() * 1000
		}()

		if time.Since(start) > 30 * time.Second {
			break
		}
	}

	// Wait for goroutines to finish by filling full channel.
	for i := 0; i < cap(limiter); i++ {
		limiter <- struct{}{}
	}

	close(results)

	println("Request latency distribution in ms:")
	println(h.String())
	println("Requests with latency more than 1000ms:", slow)
}