golang之recover时显示调用栈信息

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这是一个创建于的文章，其中的信息可能已经有所发展或是发生改变。

package main

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

func main() {
    defer fmt.Println("defer main") // will this be called when panic?
    var user = os.Getenv("USER_")

    wg := sync.WaitGroup{}
    wg.Add(1)
    go func(wgPtr *sync.WaitGroup) {
        defer func() {
            fmt.Println("go defer")
            wgPtr.Done()
        }()
        defer func() {
            fmt.Println("defer here")
        }()

        defer func() {
            fmt.Println("defer caller")
            if x := recover(); x != nil {
                fmt.Println("recover success.")
                buf := make([]byte, 1<<16)
                runtime.Stack(buf, true)
                fmt.Println("buf", string(buf))
            }
        }()

        if user == "" {
            panic("should set user env.")
        }
        fmt.Println("after panic")
    }(&wg)
    wg.Wait()
    time.Sleep(1 * time.Second)
    fmt.Printf("get result %v\r\n", user)
}

输出结果：

dev@dev-VirtualBox test $ go run test_panic_recover.go 
defer caller
recover success.
buf goroutine 6 [running]:
main.main.func1.3()
        /home/dev/test/test_panic_recover.go:31 +0x154
panic(0x4a2ce0, 0x4de010)
        /usr/local/go/src/runtime/panic.go:969 +0x166
main.main.func1(0xc000014070, 0x0, 0xc000014110)
        /home/dev/test/test_panic_recover.go:37 +0x129
created by main.main
        /home/dev/test/test_panic_recover.go:17 +0x13b

goroutine 1 [semacquire]:
sync.runtime_Semacquire(0xc000014118)
        /usr/local/go/src/runtime/sema.go:56 +0x42
sync.(*WaitGroup).Wait(0xc000014110)
        /usr/local/go/src/sync/waitgroup.go:130 +0x64
main.main()
        /home/dev/test/test_panic_recover.go:41 +0x149

defer here
go defer
get result 
defer main

其中调用栈第一行的信息 /home/dev/test/test_panic_recover.go:31，其实就是runtime.Stack(buf, true)的位置，以后的信息就是panic的发生地方和调用地方等等。

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