获取退出代码 - 转到

Question

我正在使用这个包:os/exec http://golang.org/pkg/os/exec/来在操作系统中执行命令,但我似乎找不到获取退出代码的方法.我可以读取输出

即.

package main

import(
    "os/exec"
    "bytes"
    "fmt"
    "log"
    )

func main() {
    cmd := exec.Command("somecommand", "parameter")
    var out bytes.Buffer
    cmd.Stdout = &out
    if err := cmd.Run() ; err != nil {
        //log.Fatal( cmd.ProcessState.Success() )
        log.Fatal( err )
    }
    fmt.Printf("%q\n", out.String() )
}

Answer 1

很容易确定退出代码是否为0或其他内容.在第一种情况下,cmd.Wait()将返回nil(除非在设置管道时出现另一个错误).

不幸的是,在错误情况下,没有独立于平台的方法来获取退出代码.这也是它不属于API的原因.以下代码片段适用于Linux,但我没有在其他平台上测试过:

package main

import "os/exec"
import "log"
import "syscall"

func main() {
    cmd := exec.Command("git", "blub")

    if err := cmd.Start(); err != nil {
        log.Fatalf("cmd.Start: %v", err)
    }

    if err := cmd.Wait(); err != nil {
        if exiterr, ok := err.(*exec.ExitError); ok {
            // The program has exited with an exit code != 0

            // This works on both Unix and Windows. Although package
            // syscall is generally platform dependent, WaitStatus is
            // defined for both Unix and Windows and in both cases has
            // an ExitStatus() method with the same signature.
            if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
                log.Printf("Exit Status: %d", status.ExitStatus())
            }
        } else {
            log.Fatalf("cmd.Wait: %v", err)
        }
    }
}

只要遵循 的 API 文档,以了解更多:)

Answer 2

从golang版本1.12开始，退出代码可以以本机方式和跨平台方式使用。请参见ExitError和ExitCode（）。

ExitCode返回已退出进程的退出代码；如果该进程尚未退出或被信号终止，则返回-1。

if err := cmd.Run() ; err != nil {
    if exitError, ok := err.(*exec.ExitError); ok {
        return exitError.ExitCode()
    }
}

Answer 3

这是我基于@ tux21b的答案的增强版本

utils/cmd.go

package utils

import (
    "bytes"
    "log"
    "os/exec"
    "syscall"
)

const defaultFailedCode = 1

func RunCommand(name string, args ...string) (stdout string, stderr string, exitCode int) {
    log.Println("run command:", name, args)
    var outbuf, errbuf bytes.Buffer
    cmd := exec.Command(name, args...)
    cmd.Stdout = &outbuf
    cmd.Stderr = &errbuf

    err := cmd.Run()
    stdout = outbuf.String()
    stderr = errbuf.String()

    if err != nil {
        // try to get the exit code
        if exitError, ok := err.(*exec.ExitError); ok {
            ws := exitError.Sys().(syscall.WaitStatus)
            exitCode = ws.ExitStatus()
        } else {
            // This will happen (in OSX) if `name` is not available in $PATH,
            // in this situation, exit code could not be get, and stderr will be
            // empty string very likely, so we use the default fail code, and format err
            // to string and set to stderr
            log.Printf("Could not get exit code for failed program: %v, %v", name, args)
            exitCode = defaultFailedCode
            if stderr == "" {
                stderr = err.Error()
            }
        }
    } else {
        // success, exitCode should be 0 if go is ok
        ws := cmd.ProcessState.Sys().(syscall.WaitStatus)
        exitCode = ws.ExitStatus()
    }
    log.Printf("command result, stdout: %v, stderr: %v, exitCode: %v", stdout, stderr, exitCode)
    return
}

我已经在OSX上测试了它,如果它在其他平台上没有按预期工作,请告诉我,以便我们可以做得更好.

Answer 4

2019 年 9 月，Go 1.13引入了errors.As，它支持错误“解包”——便于在嵌套调用链中查找精确错误。

因此，要在运行外部命令时提取和检查两个最常见的错误：

• os.PathError
• exec.ExitError

err := cmd.Run()

var (
    ee *exec.ExitError
    pe *os.PathError
)

if errors.As(err, &ee) {
    log.Println("exit code error:", ee.ExitCode()) // ran, but non-zero exit code

} else if errors.As(err, &pe) {
    log.Printf("os.PathError: %v", pe) // "no such file ...", "permission denied" etc.

} else if err != nil {
    log.Printf("general error: %v", err) // something really bad happened!

} else {
    log.Println("success!") // ran without error (exit code zero)
}