load test for server

go_load_test.go

package main

import (
	"flag"
	"fmt"
	"io"
	"net/http"
	"os"
	"runtime"
	"sync"
	"sync/atomic"
	"time"
)

func main() {
	runtime.GOMAXPROCS(runtime.NumCPU())
	var yes int32 = 0
	var no int32 = 0
	wg := sync.WaitGroup{}

	var worker int
	var url string
	var times int

	flag.IntVar(&times, "times", 0, "test times")
	flag.IntVar(&worker, "worker", 0, "routine count")
	flag.StringVar(&url, "url", "", "url to test")

	flag.Parse()
	if worker == 0 {
		fmt.Println("Err: no worker")
		return
	}
	if times == 0 {
		fmt.Println("Err: no times")
		return
	}
	if url == "" {
		fmt.Println("Err: no url")
		return
	}
	for i := 1; i <= times; i++ {
		if i%worker == 0 {
			wg.Wait()
		}
		wg.Add(1)
		go func() {
			defer wg.Done()
			start := time.Now()
			var err error = nil
			resp, respErr := http.Get(url)
			if respErr != nil {
				err = respErr
			} else {
				defer resp.Body.Close()
				devOut, devErr := os.OpenFile("/dev/null", os.O_WRONLY, 0666)
				if devErr != nil {
					err = devErr
				} else {
					defer devOut.Close()
					_, cpErr := io.Copy(devOut, resp.Body)
					if cpErr != nil {
						err = cpErr
					}
				}
			}

			if err != nil {
				fmt.Println(fmt.Sprintf("%s\t%s", err, time.Since(start)))
				atomic.AddInt32(&no, 1)
			} else {
				fmt.Println(time.Since(start))
				atomic.AddInt32(&yes, 1)
			}

		}()
	}
	wg.Wait()
	fmt.Println()
	fmt.Println("Ok:\t", yes)
	fmt.Println("Fail:\t", no)
}