Launch tasks and wait for finish

tasks.go

//
// Example thanks to DMorsing on #go-nuts Freenode channel
// http://play.golang.org/p/dmUfGKnbZ3
//
package main

import "fmt"
import "time"
import "math/rand"
import "sync"

var wg sync.WaitGroup

func task(ch chan bool, cancel chan struct{}) {

	defer wg.Done()

	for i := 0; i < rand.Int()%10+1; i++ {

		time.Sleep(1 * time.Second)
		// some result that was probably way expensive to calculate
		result := true
		select {
		case ch <- result:
		case <-cancel:
		}
	}
}

func main() {
	resultch := make(chan bool)
	cancelch := make(chan struct{})
	fmt.Println("Launching tasks")

	wg.Add(3)

	go task(resultch, cancelch)
	go task(resultch, cancelch)
	go task(resultch, cancelch)

	i := <-resultch
	fmt.Println("got result, it was", i)
	close(cancelch)
	fmt.Println("Quitting main...")

	wg.Wait()

}