statuschecker.go

package main

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

type cfg struct {
	sites   []string
	max     int
	results chan string
	errors  chan error
}

func main() {
	c := cfg{
		sites: []string{
			"https://www.mirkrestikom.ru/", // a slow site
			"https://google.com",
			"https://www.amazon.de",
			"https://www.github.com",
			"https://twitter.com",
			"https://no.such.host.exists",
		},
		results: make(chan string),
		errors:  make(chan error),
		max:     3,
	}

	for _, site := range c.sites {
		go check(site, c.results, c.errors)
	}

	calls := 0

	for {
		select {
		case r := <-c.results:
			fmt.Println("received on results:", r)
		case e := <-c.errors:
			fmt.Println("received on errors:", e.Error())
		}

		calls++

		if calls%len(c.sites) == 0 {
			fmt.Println("Waiting for next cycle ...")
			fmt.Println()
		}

		if calls == c.max*len(c.sites) {
			fmt.Println("Finished.")
			break
		}
	}
}

func check(site string, results chan string, errors chan error) {
	start := time.Now()
	r, err := http.Get(site)

	if err != nil {
		errors <- err
	} else {
		end := time.Since(start)
		results <- fmt.Sprintf("%s: %s [%s]", site, r.Status, end.String())
	}

	time.Sleep(10 * time.Second)

	check(site, results, errors)
}