dwelling-radio/internal/radio/liquidsoap/liquidsoap.go

package liquidsoap

import (
	"os"
	"os/exec"
	"syscall"
	"time"

	"github.com/pkg/errors"
)

var ErrNotRunning = errors.New("liquidsoap is not running")

type Liquidsoap struct {
	command *exec.Cmd
}

func NewLiquidsoap(liquidsoapPath, scriptPath string) (*Liquidsoap, error) {
	if _, err := exec.LookPath(liquidsoapPath); err != nil {
		return nil, err
	}

	cmd := exec.Command(liquidsoapPath, scriptPath)

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

	// If there are errors in a script this time will be sufficient to wait
	// for them to occure.
	time.Sleep(4 * time.Second)

	if _, err := os.FindProcess(cmd.Process.Pid); err != nil {
		if err_wait := cmd.Wait(); err != nil {
			return nil, errors.Wrap(err, err_wait.Error())
		}
		return nil, err
	}

	return &Liquidsoap{
		command: cmd}, nil
}

func (l *Liquidsoap) Stop() error {
	if !l.IsRunning() {
		return ErrNotRunning
	}

	if err := l.command.Process.Signal(syscall.SIGINT); err != nil {
		return err
	}

	if err := l.command.Wait(); err != nil {
		return err
	}

	return nil
}

func (l *Liquidsoap) IsRunning() bool {
	return l.command.Process != nil && l.command.ProcessState == nil
}