product_custome.go

package main

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

type ProductConsumer struct {
	ch chan string
	wg sync.WaitGroup
}

func (pc *ProductConsumer) Product() {
	now := time.Now()

	for c := time.Now(); c.Sub(now) < time.Duration(1 * time.Minute); {
		c = time.Now()
		taskTime := c.UnixNano()
		pc.ch <- fmt.Sprintf("%d task...\n", taskTime)
	}
	//task producted complete then close the channel
	fmt.Println("Product task complete.")
	close(pc.ch)
}

func (pc *ProductConsumer) Consume() {
	cpuNum := runtime.NumCPU()
	pc.startN(cpuNum)
}

func (pc *ProductConsumer) startN(n int) {
	for i := 0; i < n; i++ {
		pc.wg.Add(1)
		go func(n int) {pc.start(n)}(i)
	}
}

func (pc *ProductConsumer) start(n int) {
	defer pc.wg.Done()
	for task := range pc.ch {
		time.Sleep(time.Second)
		fmt.Printf("Consume the %s", task)
	}
	fmt.Printf("Consumer%d is over.\n", n)
}
func main() {
	pc := &ProductConsumer{ch: make(chan string, 100), wg: sync.WaitGroup{}}
	go pc.Product()
	pc.Consume()
	defer func() {
		pc.wg.Wait()
		fmt.Println("Main is over.")
	}()
}