create pool using gorutines,and consumes in async

async_pool.go

package main

import (
	"fmt"
	"sync"
	"time"
)

var wg sync.WaitGroup

func main() {
	ch := make(chan int, 4)
	go produce(ch)
	time.Sleep(2 * time.Second)
	consume(ch)
}

func produce(ch chan int) {
	for i := 0; i < 16; i++ {
		ch <- i
		fmt.Println("successfully wrote", i, "to ch")
	}
	close(ch)

}

func consume(ch chan int) {
	for c := range ch {
		wg.Add(1)
		go doSomething(c)
	}
	wg.Wait()
}

func doSomething(c int) {
	fmt.Println("consume:", c)
	time.Sleep(10 * time.Second)
	wg.Done()
}

create a pool using gorutines, and run in async

compare with the pool gist doc

this run in sync, and keep the pool is always 4 in capacity util the end.

print

successfully wrote 0 to ch
successfully wrote 1 to ch
successfully wrote 2 to ch
successfully wrote 3 to ch
consume: 0
successfully wrote 4 to ch
successfully wrote 5 to ch
consume: 2
consume: 6
consume: 1
consume: 4
consume: 3
successfully wrote 6 to ch
successfully wrote 7 to ch
successfully wrote 8 to ch
successfully wrote 9 to ch
successfully wrote 10 to ch
successfully wrote 11 to ch
consume: 5
consume: 12
consume: 7
consume: 10
consume: 11
successfully wrote 12 to ch
successfully wrote 13 to ch
successfully wrote 14 to ch
successfully wrote 15 to ch
consume: 15
consume: 13
consume: 14
consume: 8
consume: 9