core/sys/sys.go

package sys

import (
	"fmt"
	"io"
	"os"
	"os/exec"
	"os/signal"
	"syscall"

	"golang.org/x/sys/unix"
)

var TERM_WIDTH = 0

func RunCmd(cmd *exec.Cmd) int {
	cmd.Stdin = os.Stdin
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	return ManageStatusCmd(cmd, cmd.Run())
}

func RunShellCmd(call string) int {
	cmd := exec.Command("sh", "-c", call)
	cmd.Stdin = os.Stdin
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	return ManageStatusCmd(cmd, cmd.Run())
}

func ManageStatusCmd(cmd *exec.Cmd, err error) int {
	if err == nil {
		return 0
	}
	// Figure out the exit code
	if ws, ok := cmd.ProcessState.Sys().(syscall.WaitStatus); ok {
		if ws.Exited() {
			return ws.ExitStatus()
		}
		if ws.Signaled() {
			return -int(ws.Signal())
		}
	}
	return -1
}

func RunInteractiveCmd(cmd string, withStderr bool) int {
	fmt.Printf(" == go before command : %s\n", cmd)
	icmd := exec.Command("bash", "-c", cmd)
	icmd.Stdin = os.Stdin
	icmd.Stdout = os.Stdout
	if withStderr {
		icmd.Stderr = os.Stderr
	}
	return ManageStatusCmd(icmd, icmd.Run())
}

func PipeCmd(cmd1 *exec.Cmd, cmd2 *exec.Cmd, buffers ...io.Writer) {
	fmt.Println("> Pipe Commands")
	if len(buffers) > 0 {
		pr, pw := io.Pipe()
		cmd1.Stdout = pw
		cmd2.Stdin = pr
		cmd2.Stdout = buffers[0]
		if len(buffers) > 1 {
			cmd2.Stderr = buffers[1]
		}

		cmd1.Start()
		cmd2.Start()

		go func() {
			defer pw.Close()
			err1 := cmd1.Wait()
			if err1 != nil {
				fmt.Printf("error1 : %v\n", err1)
			}
		}()

		err2 := cmd2.Wait()
		if err2 != nil {
			fmt.Printf("error2 : %v\n", err2)
		}
		fmt.Println("< Pipe Commands")
	}
}

func UpdateTermSize() error {
	ws, err := unix.IoctlGetWinsize(syscall.Stdout, unix.TIOCGWINSZ)
	if err != nil {
		return err
	}
	TERM_WIDTH = int(ws.Col)
	return nil
}

func HandleTermChange(sigwinch chan os.Signal) {
	// set signal handler
	signal.Notify(sigwinch, syscall.SIGWINCH)
	go func() {
		for {
			if _, ok := <-sigwinch; !ok {
				return
			}
			_ = UpdateTermSize()
			fmt.Printf("TERM WIDTH : %d\n", TERM_WIDTH)
		}
	}()
}

func HandleSigKill(done chan os.Signal) {
	signal.Notify(done, syscall.SIGINT, syscall.SIGTERM)
	go func() {
		<-done // Will block here until user hits ctrl+c
		cmd := exec.Command("tput", "cnorm")
		RunCmd(cmd)
		cmd = exec.Command("tput", "-x", "clear")
		RunCmd(cmd)
		os.Exit(0)
	}()
}