go-by-test/racer/racer.go

package racer

import (
	"fmt"
	"net/http"
	"time"
)

func Racer(a, b string) string {
	select {
	// wait until channel closed
	case <-ping(a):
		return a
	case <-ping(b):
		return b
	}
}

func measureResponseTime(url string) time.Duration {
	start := time.Now()
	http.Get(url)
	duration := time.Since(start)
	fmt.Println(duration)
	return duration
}

func ping(url string) chan struct{} {
	ch := make(chan struct{})
	go func() {
		http.Get(url)
		// if got, close channel
		close(ch)
	}()
	return ch
}