fetch a list of urls in parallel by go

parallel-fetcher.go

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"sync"
)

func check(err error) {
	if err != nil {
		log.Fatal(err)
		return
	}
}

func fetchUrls(urls []string) <-chan string {
	out := make(chan string)

	var wg sync.WaitGroup
	wg.Add(len(urls))
	for _, url := range urls {
		// Increment the WaitGroup counter.
		// Launch a goroutine to fetch the URL.
		go func(url string) {
			// Decrement the counter when the goroutine completes.
			defer wg.Done()
			// Fetch the URL.
			resp, err := http.Get(url)
			check(err)
			defer resp.Body.Close()
			body, err := ioutil.ReadAll(resp.Body)
			check(err)
			out <- string(body)
		}(url)
	}
	// Wait for all HTTP fetches to complete.
	go func() {
		wg.Wait()
		defer close(out)
	}()

	return out
}

func main() {

	urls := []string{"https://httpbin.org/uuid", "https://httpbin.org/uuid"}
	body := fetchUrls(urls)

	for v := range body {
		fmt.Println(v)
	}

}