update

scanner/external.go

@@ -0,0 +1,101 @@
+package scanner
+
+import (
+	"context"
+	"encoding/gob"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+
+	"github.com/navidrome/navidrome/conf"
+	"github.com/navidrome/navidrome/log"
+	"github.com/navidrome/navidrome/model"
+)
+
+// scannerExternal is a scanner that runs an external process to do the scanning. It is used to avoid
+// memory leaks or retention in the main process, as the scanner can consume a lot of memory. The
+// external process will be spawned with the same executable as the current process, and will run
+// the "scan" command with the "--subprocess" flag.
+//
+// The external process will send progress updates to the main process through its STDOUT, and the main
+// process will forward them to the caller.
+type scannerExternal struct{}
+
+func (s *scannerExternal) scanFolders(ctx context.Context, fullScan bool, targets []model.ScanTarget, progress chan<- *ProgressInfo) {
+	s.scan(ctx, fullScan, targets, progress)
+}
+
+func (s *scannerExternal) scan(ctx context.Context, fullScan bool, targets []model.ScanTarget, progress chan<- *ProgressInfo) {
+	exe, err := os.Executable()
+	if err != nil {
+		progress <- &ProgressInfo{Error: fmt.Sprintf("failed to get executable path: %s", err)}
+		return
+	}
+
+	// Build command arguments
+	args := []string{
+		"scan",
+		"--nobanner", "--subprocess",
+		"--configfile", conf.Server.ConfigFile,
+		"--datafolder", conf.Server.DataFolder,
+		"--cachefolder", conf.Server.CacheFolder,
+	}
+
+	// Add targets if provided
+	if len(targets) > 0 {
+		for _, target := range targets {
+			args = append(args, "-t", target.String())
+		}
+		log.Debug(ctx, "Spawning external scanner process with targets", "fullScan", fullScan, "path", exe, "targets", targets)
+	} else {
+		log.Debug(ctx, "Spawning external scanner process", "fullScan", fullScan, "path", exe)
+	}
+
+	// Add full scan flag if needed
+	if fullScan {
+		args = append(args, "--full")
+	}
+
+	cmd := exec.CommandContext(ctx, exe, args...)
+
+	in, out := io.Pipe()
+	defer in.Close()
+	defer out.Close()
+	cmd.Stdout = out
+	cmd.Stderr = os.Stderr
+
+	if err := cmd.Start(); err != nil {
+		progress <- &ProgressInfo{Error: fmt.Sprintf("failed to start scanner process: %s", err)}
+		return
+	}
+	go s.wait(cmd, out)
+
+	decoder := gob.NewDecoder(in)
+	for {
+		var p ProgressInfo
+		if err := decoder.Decode(&p); err != nil {
+			if !errors.Is(err, io.EOF) {
+				progress <- &ProgressInfo{Error: fmt.Sprintf("failed to read status from scanner: %s", err)}
+			}
+			break
+		}
+		progress <- &p
+	}
+}
+
+func (s *scannerExternal) wait(cmd *exec.Cmd, out *io.PipeWriter) {
+	if err := cmd.Wait(); err != nil {
+		var exitErr *exec.ExitError
+		if errors.As(err, &exitErr) {
+			_ = out.CloseWithError(fmt.Errorf("%s exited with non-zero status code: %w", cmd, exitErr))
+		} else {
+			_ = out.CloseWithError(fmt.Errorf("waiting %s cmd: %w", cmd, err))
+		}
+		return
+	}
+	_ = out.Close()
+}
+
+var _ scanner = (*scannerExternal)(nil)