Interactive Process Shell

iprocshell.go

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"os/exec"
	"sync/atomic"
	"time"
)

var gateOpen uint32

func monitorStdout(pipe io.ReadCloser) {
	scanner := bufio.NewScanner(pipe)

	for scanner.Scan(){
		text := scanner.Text()
		if gateOpen == 1 {
			fmt.Println(text)
		}
	}
}

func startRepl(stdin io.WriteCloser, stdout io.ReadCloser) {
	scanner := bufio.NewScanner(os.Stdin)
	go monitorStdout(stdout)
	fmt.Print("# ")
	for scanner.Scan(){
		cmdtext := scanner.Text()
		if cmdtext == "quit" {
			stdin.Write([]byte{1, 120})
			break
		} else {
			atomic.StoreUint32(&gateOpen, 1)
			time.AfterFunc(1*time.Second, func() {
				atomic.StoreUint32(&gateOpen, 0)
				fmt.Print("# ")
			})
			stdin.Write([]byte{10})
			stdin.Write([]byte(cmdtext))
			stdin.Write([]byte{10})
		}
	}
}

func run(command string, args []string) {
	fmt.Println(command, args)
	cmd := exec.Command(command, args...)
	stdinPipe, _ := cmd.StdinPipe()
	stdoutPipe, _ := cmd.StdoutPipe()

	if err := cmd.Start(); err != nil {
		panic(err)
	}
	startRepl(stdinPipe, stdoutPipe)
	cmd.Process.Kill()
}


func main() {
	if len(os.Args) > 1 {
		cmdToRun := os.Args[1]

		var optionalArgs []string
		if len(os.Args) > 2 {
			optionalArgs = os.Args[2:]
		}
		run(cmdToRun, optionalArgs)	
	}
}