go - 将恢复传递给上层 goroutine golang

Question

我创建了一个示例，在该示例中我同时运行函数，在其中我会 panic 并恢复:

package main

import "fmt"

func main() {
    // "main" recovery
    defer func() {
        if r := recover(); r != nil {
            fmt.Println("main goroutine paniced:", r)
        }
    }()

    // running function concurrently inside which I panic
    chanStr := make(chan string)
    go func() {
        // this "internal" goroutin recovery
        defer func() {
            if r := recover(); r != nil {
                fmt.Println("internal goroutine paniced:", r)
            }
            chanStr <- "hello world"
        }()
        // panicking and wanting recovery not only in "internal" recovery but in "main" recovery as well
        panic("NOT main goroutine")
    }()
    // waiting for chan with "internal" goroutine panicking and recovery
    str := <-chanStr
    fmt.Println(str)

    // panic("main")
}

它给出输出:

internal goroutine panicked: NOT main goroutine
hello world

是否可以更改我的代码以将传递从“内部”恢复为“主要”？换句话说，我希望它写到控制台:

internal goroutine paniced: NOT main goroutine
main goroutine paniced: main
hello world

我试图通过完全删除“内部”恢复功能来实现这一点，但在这种情况下，“主要”恢复不会恢复“内部”goroutine 内的 panic 。

Playground

更新

我尝试遵循@Momer 的建议并通过 channel 发送错误并在主 goroutine 中处理它，而不是试图引发 panic :

package main

import (
    "errors"
    "fmt"
)

func main() {
    // "main" recovery
    defer func() {
        if r := recover(); r != nil {
            fmt.Println("main goroutine paniced:", r)
        }
    }()

    // running func concarantly inside which I panic
    chanStr := make(chan string)
    chanErr := make(chan error)
    var err error
    go func() {
        // this "internal" goroutin recovery
        defer func() {
            if r := recover(); r != nil {
                fmt.Println("internal goroutine paniced:", r)
                switch t := r.(type) {
                case string:
                    fmt.Println("err is string")
                    err = errors.New(t)
                case error:
                    fmt.Println("err is error")
                    err = t
                default:
                    fmt.Println("err is unknown")
                    err = errors.New("Unknown error")
                }

                chanErr <- err
                chanStr <- ""
            }
        }()
        // panicing and wanting recovery not only in "internal" recovery but in "main" recovery as well
        panic("NOT main goroutine")
        chanStr <- "hello world"
        chanErr <- nil

    }()
    // waiting for chan with "internal" goroutin panicing and recovery
    str := <-chanStr
    err = <-chanErr
    fmt.Println(str)
    fmt.Println(err)

    // panic("main")
}

报错

all goroutines are asleep - deadlock

完整输出:

go run /goPath/parentRecoverty2.go
internal goroutine paniced: NOT main goroutine
err is string
fatal error: all goroutines are asleep - deadlock!

goroutine 1 [chan receive]:
main.main()
    /goPath/parentRecoverty2.go:48 +0x1d4

goroutine 5 [chan send]:
main.func·002()
    /goPath/parentRecoverty2.go:37 +0x407
main.func·003()
    /goPath/parentRecoverty2.go:42 +0x130
created by main.main
    /goPath/parentRecoverty2.go:46 +0x190
exit status 2

Update playground

Answer 1

我将 golang 中的 panic/recover 视为 java 或 c++ 中的 try/catch/final block 。

更多详情，您可以访问Handling panics (from Golang spec) .

因此您可以将 panic 传递给方法的调用者。下面是一个简单的代码，希望对您有所帮助

注意:在函数 Foo() 中，我使用 recover() 来捕捉出错的地方，然后重新 panic 以便稍后在外部调用者中捕捉它。

package main

import (
    "fmt"
    "time"
)

func Foo() {
    defer func() {
        if x := recover(); x != nil {
            fmt.Printf("Runtime panic: %v \n", x)
            panic("Ah oh ... Panic in defer")
        }
    }()
    panic("Panic in Foo() !")
}

func Game() {
    defer func(){
        fmt.Println("Clean up in Game()")
    }()

    defer func() {
        if x := recover(); x != nil {
            fmt.Println("Catch recover panic !!! In Game()")
        }
    }()
    Foo()

}

func main() {

    defer func() {
        fmt.Println("Program Quit ... ")
    }()

    fmt.Println("-----------Split-------------")
    go Game()
    time.Sleep(1 * time.Millisecond)
    fmt.Println("-----------Split-------------")
}