go_waitgroup_parallel_url_fetch_concurrency_quickstart.go

1package main
2
3import (
4	"sync"
5	"net/http"
6)
7
8func main() {
9	var wg sync.WaitGroup
10	var urls = []string{
11		"http://www.golang.org/",
12		"http://www.google.com/",
13		"http://www.somewhere.com/",
14	}
15	for _, url := range urls {
16		// Increment the WaitGroup counter.
17		wg.Add(1)
18		// Launch a goroutine to fetch the URL.
19		go func(url string) {
20			// Decrement the counter when the goroutine completes.
21			defer wg.Done()
22			// Fetch the URL.
23			http.Get(url)
24		}(url)
25	}
26	// Wait for all HTTP fetches to complete.
27	wg.Wait()
28}