go语言将cmd stdout和stderr作为字符串返回而不是打印到控制台

本文介绍: go语言将cmd stdout和stderr作为字符串返回而不是打印到控制台

go语言将cmd stdout和stderr作为字符串返回而不是打印到控制台

1、直接打印到控制台

从 golang 应用程序中执行 bash 命令，现在 stdout 和 stderr 直接进入控制台：

cmd.Stdout = os.Stdout 
cmd.Stderr = os.Stderr

package main

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

func main() {
	ok, outString, errString := runBashCommandAndKillIfTooSlow("dir", 2000)
	fmt.Println("ok")
	fmt.Println(ok)
	fmt.Println("outString")
	fmt.Println(outString)
	fmt.Println("errString")
	fmt.Println(errString)
}

/*
	run bash command and kill it if it works longer than "killInMilliSeconds" milliseconds
*/
func runBashCommandAndKillIfTooSlow(command string, killInMilliSeconds time.Duration) (okResult bool, stdout, stderr string) {
	fmt.Println("running bash command...")
	fmt.Println(command)
	// Linux
	// cmd := exec.Command("sh", "-c", command)
	// Windows
	cmd := exec.Command("cmd", "/C", command)
	cmd.Stdout = os.Stdout // cmd.Stdout -> stdout
	cmd.Stderr = os.Stderr // cmd.Stderr -> stderr
	okResult = true
	err := cmd.Start()
	log.Printf("Waiting for command to finish...")
	done := make(chan error, 1)
	go func() {
		done <- cmd.Wait()
	}()
	select {
	case <-time.After(killInMilliSeconds * time.Millisecond):
		if err := cmd.Process.Kill(); err != nil {
			log.Fatal("failed to kill: ", err)
			okResult = false
		}
		// allow goroutine to exit
		<-done
		log.Println("process killed")
	case err := <-done:
		if err != nil {
			log.Printf("process done with error = %v", err)
			okResult = false
		}
	}
	if err != nil {
		log.Fatal(err)
		okResult = false
	}
	return
}

如果 bash 命令太慢( killInMilliSeconds 参数)，程序应该保持其终止 bash 命令的能力。

希望 stdout 和 stderr 作为字符串变量从 runBashCommandAndKillIfTooSlow 函数返回，而不立即打印到控

制台，如何实现。

2、不打印到控制台

将输出设置为 strings.Builder 或 bytes.Buffer：

var outbuf, errbuf strings.Builder // or bytes.Buffer
cmd.Stdout = &outbuf
cmd.Stderr = &errbuf

运行命令后，您可以通过调用 Builder.String() 获取字符串形式的标准输出和标准错误：

stdout := outbuf.String()
stderr := errbuf.String()

package main

import (
	"fmt"
	"log"
	"os/exec"
	"strings"
	"time"
)

func main() {
	ok, outString, errString := runBashCommandAndKillIfTooSlow("dir", 2000)
	fmt.Println("ok")
	fmt.Println(ok)
	fmt.Println("outString")
	fmt.Println(outString)
	fmt.Println("errString")
	fmt.Println(errString)
}

/*
	run bash command and kill it if it works longer than "killInMilliSeconds" milliseconds
*/
func runBashCommandAndKillIfTooSlow(command string, killInMilliSeconds time.Duration) (okResult bool, stdout, stderr string) {
	fmt.Println("running bash command...")
	fmt.Println(command)
	// Linux
	// cmd := exec.Command("sh", "-c", command)
	// Windows
	cmd := exec.Command("cmd", "/C", command)
	var outBuf, errBuf strings.Builder // or bytes.Buffer
	cmd.Stdout = &outBuf
	cmd.Stderr = &errBuf
	okResult = true
	err := cmd.Start()
	log.Printf("Waiting for command to finish...")
	done := make(chan error, 1)
	go func() {
		done <- cmd.Wait()
	}()
	select {
	case <-time.After(killInMilliSeconds * time.Millisecond):
		if err := cmd.Process.Kill(); err != nil {
			log.Fatal("failed to kill: ", err)
			okResult = false
		}
		// allow goroutine to exit
		<-done
		log.Println("process killed")
	case err := <-done:
		if err != nil {
			log.Printf("process done with error = %v", err)
			okResult = false
		}
	}
	if err != nil {
		log.Fatal(err)
		okResult = false
	}
	stdout = outBuf.String()
	stderr = errBuf.String()
	return
}