dongtaochan0777
dongtaochan0777
2017-01-01 12:09
浏览 135
已采纳

在Golang中运行外部python,捕获连续的exec.Command Stdout

So my go script will call an external python like this

cmd = exec.Command("python","game.py")
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
go func(){
    err := cmd.Run()
    if err != nil{
    panic(err)
    }
}()

It runs my python script concurrently which is awesome. But now the problem is, my python script will run infinitely and it will print out some information from time to time. I want to "catch" these Stdout and print them out on my golang terminal. How do I do it concurrently (without waiting my python script to exit)?

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1条回答 默认 最新

  • dt1888
    dt1888 2017-01-01 12:29
    已采纳

    Use cmd.Start() and cmd.Wait() instead of cmd.Run().

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

    Run starts the specified command and waits for it to complete.

    Start starts the specified command but does not wait for it to complete.

    Wait waits for the command to exit. It must have been started by Start.

    And if you want to capture stdout/stderr concurrently, use cmd.StdoutPipe() / cmd.StderrPipe() and read it by bufio.NewScanner()

    package main
    
    import (
        "bufio"
        "fmt"
        "io"
        "os/exec"
    )
    
    func main() {
        cmd := exec.Command("python", "game.py")
        stdout, err := cmd.StdoutPipe()
        if err != nil {
            panic(err)
        }
        stderr, err := cmd.StderrPipe()
        if err != nil {
            panic(err)
        }
        err = cmd.Start()
        if err != nil {
            panic(err)
        }
    
        go copyOutput(stdout)
        go copyOutput(stderr)
        cmd.Wait()
    }
    
    func copyOutput(r io.Reader) {
        scanner := bufio.NewScanner(r)
        for scanner.Scan() {
            fmt.Println(scanner.Text())
        }
    }
    

    The following is a sample python code for reproducing real-time output. The stdout may be buffered in Python. Explicit flush may be required.

    import time
    import sys
    
    while True:
        print "Hello"
        sys.stdout.flush()
        time.sleep(1)
    
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