Golang: Playing with a queue channel

kanal.go

package main

import (
	"bufio"
	"fmt"
	"math/rand"
	"os"
	"strconv"
	"time"
)

const (
	queueSize       = 9
	numberOfReaders = 3
)

var readerSleepInterval = struct{ min, max int }{0, 2}

var queue = make(chan int, queueSize)
var done = make(chan bool)

func main() {

	fmt.Println("=== Playing with a simple queue ===")
	fmt.Printf("  Queue size: %v\n", queueSize)
	fmt.Printf("  Number of readers: %v\n", numberOfReaders)
	fmt.Printf("  Reader sleep interval from %v to %v seconds\n", readerSleepInterval.min, readerSleepInterval.max)

	fmt.Printf("Forking %v readers\n  ", numberOfReaders)
	for i := 0; i < numberOfReaders; i++ {
		fmt.Printf("#%v ", i)
		go queueReader(i)
	}
	fmt.Println("")

	fmt.Println("Forking the Producer")
	go queueProducer()

	fmt.Println("Waiting for quit from the Producer")
	<-done
	fmt.Println("Done!")
}

// Producer will ask user to input number of items to put in queue
// If number exceeds the queue size, it hang until the queue can
// accept more items, then it will push more items on the queue
func queueProducer() {

	reader := bufio.NewReader(os.Stdin)

	for {
		fmt.Printf("Number of items to add (quit to exit): ")
		bytes, _, err := reader.ReadLine()
		if err != nil {
			fmt.Println(err.Error())
			continue
		}

		val := string(bytes)

		if val == "quit" {
			done <- true
			return
		}

		n, err := strconv.Atoi(val)
		if err != nil {
			fmt.Println("Enter a number, please!")
			continue
		}

		for i := 0; i < n; i++ {
			queue <- i
		}

	}
}

// Reader will read from queue and then pretend to process it for a
// random(ish) number of seconds.
func queueReader(n int) {
	for {
		val := <-queue

		rsi := readerSleepInterval
		s := rand.Intn(rsi.max-rsi.min) + rsi.min

		fmt.Printf("  Reader #%v read %v from queue, processing for %v seconds\n", n, val, s)

		time.Sleep(time.Duration(s) * time.Second)
	}
}