如何使用 Channels 让 goroutines 相互通信

Question

我是 Golang 的新手，我正在尝试使用 goroutines 以便它们之间可以交谈。我有一些代码可以启动一个具有 operation1 的 goroutine，我称之为跳舞。当它完成时，它会向另一个 goroutine 发出信号，该 goroutine 执行另一个操作 2，比方说睡眠。

你可以传递一个force dance参数给dance goroutine，但是如果它已经处于dance状态，它就会休眠。

package main

import (
    "fmt"
    "time"
)

func main(){
    test("notdancing", true)
    time.Sleep(10*time.Second)
}
func dance()error{
    fmt.Println("Tapping my feet")
    time.Sleep(10*time.Second)
    return nil
}
func test(status string, forceDance bool) {

这在

时不起作用

   //startSleep := make(chan bool)

为什么需要为频道提供缓冲区长度才能使其正常工作？我试过没有缓冲区长度，但它说如果我不传递 1 作为第二个参数，所有 goroutines 都睡着了。

    startdance := make(chan bool, 1)
    startSleep := make(chan bool, 1)

    if status == "dancing" && forceDance {
        select {
        case startSleep <-true:
            fmt.Println("Would start to sleep now")
        default:
            fmt.Println("Sleep Already started. No need to force")
        }
    }

    if status != "dancing" {
        fmt.Println("Startingdance")
        startdance <- true
    }

    go func() {
        <-startdance
        err := dance()
        if err == nil {
            select {
            case startSleep <- true:
                fmt.Println("Starting Sleeping, dancing completed")
            default:
                fmt.Println("Already started Sleeping")
            }
        } else {
            fmt.Println("Not in a mood to dance today")
        }
    }()

    go func() {
        <-startSleep
        if forceDance {
            fmt.Println("Force sleep because forcing to dance while already dancing")
        }
    }()

}

非常感谢对代码的任何更正以及使用此方法的陷阱。

Answer 1

在无缓冲通道的情况下（未指定大小时）它不能保存值，因为它没有大小。因此 reader 必须在 writing/transmiting 数据通过通道时出现，否则它将阻塞调用。

func main() {
    startDance := make(chan bool)
    startDance <- true
}

但是当您在上面的代码中指定一个大小（比如 1）时，它不会成为死锁，因为它将 space 来保存数据。 ((https://robertbasic.com/blog/buffered-vs-unbuffered-channels-in-golang/) .)(https://www.golang-book.com/books/intro/10) 您可以查看上述网站以更好地了解通道和并发性

package main

import (
    "fmt"
    "time"
)

func main() {
    startDance := make(chan bool)
    startSleep := make(chan bool)
    forceSleep := make(chan bool)
    go startDance1(startDance, forceSleep, startSleep)
    go performSleep(startSleep, startDance)
    startDance <- true
    fmt.Println("now dance is started ")
    forceSleep <- true
    select {}
}

func startDance1(startDance chan bool, forceSleep chan bool, startSleep chan bool) {

    fmt.Println("waiting to start dance")
    select {
    case <-startDance:
        fmt.Println("staring dance")
    }

    for {
        select {
        case <-startDance:
            fmt.Println("starting dance")
        case <-forceSleep:
            fmt.Println("aleardy dancing going to sleep")
            select {
            case startSleep <- true:

            default:
            }
        default:
            //this is just to show working this
            // i added default or else this will go into deadlock
            fmt.Println("dancing")
            time.Sleep(time.Second * 1)
        }
    }
}

func performSleep(startSleep chan bool, startDance chan bool) {
    select {
    case <-startSleep:
        fmt.Println("staring sleep")
    }
    fmt.Println("sleeping for 5 seconds ")
    time.Sleep(time.Second * 5)
    select {
    case startDance <- true:
        fmt.Println("started dance")
    default:
        fmt.Println("failed to start dance ")
    }
}

上面的代码比你的代码稍有改进（我试着按照你的要求做了）。我建议你阅读一些书籍来了解更多关于 go 并发的知识 (https://www.golang-book.com/books/intro/10_

如何使用 Channels 让 goroutines 相互通信

How to make goroutines talk to each other using Channels

go

goroutine