go - 如何获取命令的输出

Question

我正在从Go代码中调用python脚本:

package main
import (
    "os/exec"
    "os"
    "fmt"
    "time"
    "encoding/json"
)

func main() {
    cmd := exec.Command("python","/home/devendra/Desktop/sync/blur_multithread.py","http://4.imimg.com/data4/TP/ED/NSDMERP-28759633/audiovideojocks.png")
    var logs=make(map[string]interface{})
    logs["tes"]=os.Stdout
    _ = cmd.Run()   
    WriteLogs(logs)//Writelog is my function which logs everything in a file
}

func WriteLogs(logs map[string]interface{}){
  currentTime := time.Now().Local()
  jsonLog, err := json.Marshal(logs)
  if err != nil {
    fmt.Println(err.Error())
  }

  jsonLogString := string(jsonLog[:len(jsonLog)])
  logfile := "/home/devendra/ImageServiceLogs/"+ "ImageServiceLogs_" + currentTime.Format("2006-01-02") + ".txt"
  if logfile == "" {
    fmt.Println("Could not find logfile in configuration ...!!!")
  } else {

    jsonLogFile, err := os.OpenFile(logfile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
    defer jsonLogFile.Close()
    if err != nil {
      fmt.Println(err.Error())
    }

    jsonLogFile.WriteString(jsonLogString + "\n")
  }
}

但是当我的python脚本给我输出时，tes字段的日志值是null。如何在我的代码中获取python脚本的输出？

Answer 1

根据官方文档示例，exec.Cmd.Ouput() ([]byte, error)将在命令运行完成后为您提供命令的sdout。

https://golang.org/pkg/os/exec/#Cmd.Output

package main

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

func main() {
    out, err := exec.Command("date").Output()
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("The date is %s\n", out)
}

要同时接收该过程的stdout和stderr，编写者应使用 exec.Cmd.CombinedOutput https://golang.org/pkg/os/exec/#Cmd.CombinedOutput

如果有人想实时接收到其终端的命令输出，则编写者应将 exec.Cmd.Stdout和 exec.Cmd.Stderr属性分别设置为 os.Stdout和 os.Stderr，并调用 exec.Cmd.Run() error方法。

https://golang.org/pkg/os/exec/#Cmd
https://golang.org/pkg/os/exec/#Cmd.Run

package main

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

func main() {
    cmd := exec.Command("date")
    cmd.Stdout = os.Stdout
    cmd.Stderr = os.Stderr
    err := cmd.Run()
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("The date is %s\n", out)
}

要转发输出并同时捕获输出，编写者应寻求 io包的帮助以使用 io.MultiWriter
https://golang.org/pkg/io/#MultiWriter

package main

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

func main() {
    stdout := new(bytes.Bufer)
    stderr := new(bytes.Bufer)
    cmd := exec.Command("date")
    cmd.Stdout = io.MultiWriter(os.Stdout, stdout)
    cmd.Stderr = io.MultiWriter(os.Stderr, stderr)
    err := cmd.Run()
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("The date is %s\n", out)
}

或者，您可以使用 exec.Cmd.{Stdout,Stderr}Pipe()参见官方文档示例 https://golang.org/pkg/os/exec/#Cmd.StdoutPipe