Go Semaphore

package main
import (
	"fmt"
	"sync"
	"time"
)
type semaphore chan bool
func (s semaphore) acquire() {
	s <- true
}
func (s semaphore) release() {
	<-s
}
func main() {
	s := make(semaphore, 10) // Only 10 goroutines will be active at a time
	wg := new(sync.WaitGroup)
	wg.Add(100) // There will be 100 executions before exiting
	for i := 0; i < 100; i++ {
		s.acquire()
		go func(i int, s semaphore, wg *sync.WaitGroup) {
			defer wg.Done()
			defer s.release()
			doWork(i)
		}(i, s, wg)
	}
	wg.Wait()
}
func doWork(i int) {
	fmt.Printf("i=%d\n", i)
	time.Sleep(500 * time.Millisecond)
}

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