stupid_goroutine_example.go

package main

import (
	"fmt"
	"math/rand"
)

func main() {
	doneCh := make(chan bool)

	worker := func(n int, msgQueue chan int, printChan chan<- string, doneChan <-chan bool) {
		for {
			msgData := rand.Intn(10)
			select {
			case msg := <-msgQueue:
				printChan <- fmt.Sprintln(n, "receive", msg)
			case msgQueue <- msgData:
				printChan <- fmt.Sprintln(n, "send", msgData)
			case <-doneCh:
				return
			}
		}
	}

	printWorker := func(printChan <-chan string, doneChan <-chan bool) {
		for {
			select {
			case <-doneCh:
				return
			case msg := <-printChan:
				fmt.Print(msg)
			}
		}
	}

	msgChan := make(chan int)
	printChan := make(chan string)
	for i := 0; i < 10; i++ {
		go worker(i, msgChan, printChan, doneCh)
	}
	go printWorker(printChan, doneCh)

	<-doneCh
}