wit-debian-gui/os.go

package main

import (
	"bufio"
	"errors"
	"io/ioutil"
	"os"
	"os/exec"
	"strings"

	"go.wit.com/log"
	"github.com/davecgh/go-spew/spew"
)

func runSimpleCommand(s string) {
	cmd := strings.TrimSpace(s)         // this is like 'chomp' in perl
	cmd = strings.TrimSuffix(cmd, "\n") // this is like 'chomp' in perl
	cmdArgs := strings.Fields(cmd)
	runLinuxCommand(cmdArgs)
}

func xterm(cmd string) {
	var tmp []string
	var argsXterm = []string{"nohup", "xterm", "-geometry", geom}
	tmp = append(argsXterm, "-hold", "-e", cmd)
	log.Println("xterm cmd=", cmd)
	go runCommand(tmp)
}

func runCommand(cmdArgs []string) {
	log.Println("runCommand() START", cmdArgs)
	process := exec.Command(cmdArgs[0], cmdArgs[1:len(cmdArgs)]...)
	// process := exec.Command("xterm", "-e", "ping localhost")
	log.Println("runCommand() process.Start()")
	process.Start()
	log.Println("runCommand() process.Wait()")
	err := process.Wait()
	lookupError(err)
	log.Println("runCommand() NEED TO CHECK THE TIME HERE TO SEE IF THIS WORKED")
	log.Println("runCommand() OTHERWISE INFORM THE USER")
	log.Println("runCommand() END", cmdArgs)
}

func lookupError(err error) {
	var (
		ee *exec.ExitError
		pe *os.PathError
	)

	if errors.As(err, &ee) {
		log.Println("ran, but non-zero exit code =", 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("something really bad happened general err = %v", err) // something really bad happened!
		if exitError, ok := err.(*exec.ExitError); ok {
			log.Printf("exitError.ExitCode() is %d\n", exitError.ExitCode())
		}
	} else {
		log.Println("success! // ran without error (exit code zero)")
	}
}

func runLinuxCommand(cmdArgs []string) (string, error) {
	process := exec.Command(cmdArgs[0], cmdArgs[1:len(cmdArgs)]...)

	process.Stdin = os.Stdin
	process.Stderr = os.Stderr

	stdOut, err := process.StdoutPipe()
	if err != nil {
		return "", err
	}

	if err := process.Start(); err != nil {
		return "", err
	}

	bytes, err := ioutil.ReadAll(stdOut)
	if err != nil {
		return "", err
	}
	err = process.Wait()
	lookupError(err)

	log.Println(string(bytes))
	return string(bytes), err
}

func packrSaveFile(packrname string, filename string) error {
	log.Println("packrSaveFile() for", packrname)
	b, _ := packrBox.FindString(packrname)
	log.Println(packrname, "=\n\n", b)
	spew.Dump(b)

	f, err := os.Create(filename)
	if err != nil {
		return err
	}
	defer f.Close()
	w := bufio.NewWriter(f)
	n4, err := w.WriteString(b)
	log.Println("n4 =", n4)
	w.Flush()
	return nil
}

// run something and never return from it
// TODO: pass STDOUT, STDERR, STDIN correctly
// TODO: figure out how to nohup the process and exit
func bash(cmdline string) error {
	log.Println("shell.Run() START " + cmdline)

	cmdArgs := strings.Fields(cmdline)

	process := exec.Command(cmdArgs[0], cmdArgs[1:len(cmdArgs)]...)
	process.Stderr = os.Stderr
	process.Stdin = os.Stdin
	process.Stdout = os.Stdout
	process.Start()
	err := process.Wait()
	log.Println("shell.Exec() err =", err)
	return err
	// os.Exit(0)
}

func sudo(f func() error) error {
	uid := os.Getuid()
	e := "You must be root to do this."
	log.Println(e, "uid =", uid)
	if uid != 0 {
		log.Warn("Permissions Failed", e)
		return errors.New("not root")
	}
	err := f()
	return err
}