Golang concurrency

concurrency.go

package main

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

func main() {
	start := time.Now()

	channel := make(chan string)

	sites := []struct{ name, url string }{
		{"Go", "http://golang.org"},
		{"Haskell", "http://haskell.org"},
		{"Python", "http://python.org"},
	}

	for _, site := range sites {
		go get(site.name, site.url, channel)
	}

	for i := 0; i < len(sites); i++ {
		fmt.Print(<-channel)
	}

	duration := time.Since(start).Seconds()
	fmt.Printf("Finished in %.2f seconds", duration)
}

func get(name, url string, channel chan<- string) {
	start := time.Now()
	res, err := http.Get(url)

	if err != nil {
		channel <- fmt.Sprintf("%s: %s", name, err)
		return
	}

	size, _ := io.Copy(ioutil.Discard, res.Body)
	res.Body.Close()

	duration := time.Since(start).Seconds()
	channel <- fmt.Sprintf("%s (%s) [%d bytes in %.2fs]\n", name, url, size, duration)
}