goruntine不同时运行？

我有下面的程序，我是gorountine的新手，我想测试的很简单，我在循环中调用gorountine 100次，如果有一次失败，整个程序失败，否则成功，

fail10Percent

它延迟1秒，如果是4，则检查一个随机数，让它失败

package main

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

func fail10Percent(ch chan int) {
    time.Sleep(1 * time.Second)
    e := rand.Intn(10)
    fmt.Println("Calculating rand.Intn(10) ", e)

    if e == 4 {
        ch <- 0
        return
    }
    ch <- 1
}

func test() {
    for i := 0; i < 100; i++ {
        err := make(chan int)
        go fail10Percent(err)

        res := <-err

        fmt.Println("=== result: ", res)

        if res != 1 {
            fmt.Println("failed")
            return
        }
    }
    fmt.Println("succeeded")
}

func main() {
    test()
}

---

我已经为您注释了代码，以便您能够理解

package main

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

func fail10Percent(ch chan int, w *sync.WaitGroup) {
    defer w.Done()
    num := rand.Intn(10)
    fmt.Println("calculating rand.Intn(10) ", num)
    if num == 4 {
        ch <- 0 // Fail
        return
    }
    ch <- 1 // Pass
}

func test() {
    var ch = make(chan int, 1)
    // Launch the receiver goroutine to listen if goroutine succeeded or failed based on the value sent to ch
    go func() {
        for recv := range ch {
            switch recv {
            // Fail
            case 0:
                fmt.Println("goroutine failed")
            // Pass
            case 1:
                fmt.Println("goroutine succeed")
            }
        }
    }()
    // wg is a WaitGroup
    var wg sync.WaitGroup
    for i := 0; i < 100; i++ {
        wg.Add(1)
        go fail10Percent(ch, &wg)
    }
    // wg.Wait() to wait for all goroutines to complete
    wg.Wait()
    // Close the channel so that the receiver can stop
    close(ch)
}

func main() {
    test()
}

---

因为您使用的是无缓冲通道，所以main只需等待，直到它接收到通道上的内容。我建议您学习围棋和其他围棋基础知识。当goroutine失败时，整个程序都会失败，因为当您检查

res！=1

，您从测试函数返回，导致主goroutine退出，因此程序终止。

package main

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

func fail10Percent(ch chan int, w *sync.WaitGroup) {
    defer w.Done()
    num := rand.Intn(10)
    fmt.Println("calculating rand.Intn(10) ", num)
    if num == 4 {
        ch <- 0 // Fail
        return
    }
    ch <- 1 // Pass
}

func test() {
    var ch = make(chan int, 1)
    // Launch the receiver goroutine to listen if goroutine succeeded or failed based on the value sent to ch
    go func() {
        for recv := range ch {
            switch recv {
            // Fail
            case 0:
                fmt.Println("goroutine failed")
            // Pass
            case 1:
                fmt.Println("goroutine succeed")
            }
        }
    }()
    // wg is a WaitGroup
    var wg sync.WaitGroup
    for i := 0; i < 100; i++ {
        wg.Add(1)
        go fail10Percent(ch, &wg)
    }
    // wg.Wait() to wait for all goroutines to complete
    wg.Wait()
    // Close the channel so that the receiver can stop
    close(ch)
}

func main() {
    test()
}