Go queue with a buffered channel

queue.go

package main

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

func produce(q chan<- int, n int) {
	var a int
	for a < n {
		q <- a
		a++
	}

	close(q)
}

func consume(q <-chan int, wg *sync.WaitGroup) {
	for a := range q {
		time.Sleep(time.Millisecond * time.Duration(rand.Intn(1000)))
		fmt.Println(a)
	}

	wg.Done()
}

func main() {
	const (
		numberOfConsumers = 9
		numberItems       = 100
		queueCapacity     = numberOfConsumers * 3
	)

	q := make(chan int, queueCapacity)
	var wg sync.WaitGroup
	go produce(q, numberItems)
	for i := 0; i < numberOfConsumers; i++ {
		wg.Add(1)
		go consume(q, &wg)
	}

	wg.Wait()
}