refactoring-1

introduced pipelines and abstracted download process.go in Downloader interface

server/internal/downloaders/livestream.go

@@ -0,0 +1,205 @@
+package downloaders
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"log/slog"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"slices"
+	"syscall"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/common"
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/config"
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/internal"
+	"github.com/marcopiovanello/yt-dlp-web-ui/v3/server/internal/pipes"
+)
+
+type LiveStreamDownloader struct {
+	progress internal.DownloadProgress
+
+	proc *os.Process
+
+	logConsumer LogConsumer
+
+	pipes []pipes.Pipe
+
+	// embedded
+	DownloaderBase
+}
+
+func NewLiveStreamDownloader(url string, pipes []pipes.Pipe) Downloader {
+	l := &LiveStreamDownloader{
+		logConsumer: NewFFMpegLogConsumer(),
+		pipes:       pipes,
+	}
+	// in base
+	l.Id = uuid.NewString()
+	l.URL = url
+	return l
+}
+
+func (l *LiveStreamDownloader) Start() error {
+	l.SetPending(true)
+
+	baseParams := []string{
+		l.URL,
+		"--newline",
+		"--no-colors",
+		"--no-playlist",
+		"--no-exec",
+	}
+
+	params := append(baseParams, "-o", "-")
+
+	cmd := exec.Command(config.Instance().DownloaderPath, params...)
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+
+	// stdout = media stream
+	media, err := cmd.StdoutPipe()
+	if err != nil {
+		slog.Error("failed to get media stdout", slog.Any("err", err))
+		panic(err)
+	}
+
+	// stderr = log/progress
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		slog.Error("failed to get stderr pipe", slog.Any("err", err))
+		panic(err)
+	}
+
+	if err := cmd.Start(); err != nil {
+		slog.Error("failed to start yt-dlp process", slog.Any("err", err))
+		panic(err)
+	}
+
+	l.proc = cmd.Process
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer func() {
+		l.Complete()
+		cancel()
+	}()
+
+	// --- costruisci pipeline ---
+	reader := io.Reader(media)
+	for _, pipe := range l.pipes {
+		nr, err := pipe.Connect(reader)
+		if err != nil {
+			slog.Error("pipe failed", slog.String("pipe", pipe.Name()), slog.Any("err", err))
+			return err
+		}
+		reader = nr
+	}
+
+	// --- fallback: se nessun FileWriter, scrivi su file ---
+	if !l.hasFileWriter() {
+		go func() {
+			filepath.Join(
+				config.Instance().DownloadPath,
+				fmt.Sprintf("%s (live) %s.mp4", l.Id, time.Now().Format(time.ANSIC)),
+			)
+
+			defaultPath := filepath.Join(config.Instance().DownloadPath)
+			f, err := os.Create(defaultPath)
+			if err != nil {
+				slog.Error("failed to create fallback file", slog.Any("err", err))
+				return
+			}
+			defer f.Close()
+
+			_, err = io.Copy(f, reader)
+			if err != nil {
+				slog.Error("copy error", slog.Any("err", err))
+			}
+			slog.Info("download saved", slog.String("path", defaultPath))
+		}()
+	}
+
+	// --- logs consumer ---
+	logs := make(chan []byte)
+	go produceLogs(stderr, logs)
+	go consumeLogs(ctx, logs, l.logConsumer, l)
+
+	l.progress.Status = internal.StatusLiveStream
+
+	return cmd.Wait()
+}
+
+func (l *LiveStreamDownloader) Stop() error {
+	defer func() {
+		l.progress.Status = internal.StatusCompleted
+		l.Complete()
+	}()
+	// yt-dlp uses multiple child process the parent process
+	// has been spawned with setPgid = true. To properly kill
+	// all subprocesses a SIGTERM need to be sent to the correct
+	// process group
+	if l.proc == nil {
+		return errors.New("*os.Process not set")
+	}
+
+	pgid, err := syscall.Getpgid(l.proc.Pid)
+	if err != nil {
+		return err
+	}
+	if err := syscall.Kill(-pgid, syscall.SIGTERM); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (l *LiveStreamDownloader) Status() *internal.ProcessSnapshot {
+	return &internal.ProcessSnapshot{
+		Id:             l.Id,
+		Info:           l.Metadata,
+		Progress:       l.progress,
+		DownloaderName: "livestream",
+	}
+}
+
+func (l *LiveStreamDownloader) UpdateSavedFilePath(p string) {}
+
+func (l *LiveStreamDownloader) SetOutput(o internal.DownloadOutput)     {}
+func (l *LiveStreamDownloader) SetProgress(p internal.DownloadProgress) { l.progress = p }
+
+func (l *LiveStreamDownloader) SetMetadata(fetcher func(url string) (*common.DownloadMetadata, error)) {
+	l.FetchMetadata(fetcher)
+}
+
+func (l *LiveStreamDownloader) SetPending(p bool) {
+	l.Pending = p
+}
+
+func (l *LiveStreamDownloader) GetId() string  { return l.Id }
+func (l *LiveStreamDownloader) GetUrl() string { return l.URL }
+
+func (l *LiveStreamDownloader) RestoreFromSnapshot(snap *internal.ProcessSnapshot) error {
+	if snap == nil {
+		return errors.New("cannot restore nil snapshot")
+	}
+
+	s := *snap
+
+	l.Id = s.Id
+	l.URL = s.Info.URL
+	l.Metadata = s.Info
+	l.progress = s.Progress
+
+	return nil
+}
+
+func (l *LiveStreamDownloader) IsCompleted() bool { return l.Completed }
+
+func (l *LiveStreamDownloader) hasFileWriter() bool {
+	return slices.ContainsFunc(l.pipes, func(p pipes.Pipe) bool {
+		return p.Name() == "file-writer"
+	})
+}