Example
A common technique for using channels is to create some number of workers (or consumers) to read from the channel. Using a sync.WaitGroup is an easy way to wait for those workers to finish running.
package main
import (
"fmt"
"sync"
"time"
)
func main() {
numPiecesOfWork := 20
numWorkers := 5
workCh := make(chan int)
wg := &sync.WaitGroup{}
// Start workers
wg.Add(numWorkers)
for i := 0; i < numWorkers; i++ {
go worker(workCh, wg)
}
// Send work
for i := 0; i < numPiecesOfWork; i++ {
work := i % 10 // invent some work
workCh <- work
}
// Tell workers that no more work is coming
close(workCh)
// Wait for workers to finish
wg.Wait()
fmt.Println("done")
}
func worker(workCh <-chan int, wg *sync.WaitGroup) {
defer wg.Done() // will call wg.Done() right before returning
for work := range workCh { // will wait for work until workCh is closed
doWork(work)
}
}
func doWork(work int) {
time.Sleep(time.Duration(work) * time.Millisecond)
fmt.Println("slept for", work, "milliseconds")
}
