Fix SIGUSR1 work when ScanInterval=0

cmd/root.go

@@ -53,8 +53,16 @@ func runNavidrome() {
 	db.EnsureLatestVersion()
 
 	var g run.Group
+
 	g.Add(startServer())
-	g.Add(startScanner())
+	g.Add(startSignaler())
+
+	interval := conf.Server.ScanInterval
+	if interval != 0 {
+		g.Add(startScanner(interval))
+	} else {
+		log.Warn("Periodic scan is DISABLED", "interval", interval)
+	}
 
 	if err := g.Run(); err != nil {
 		log.Error("Fatal error in Navidrome. Aborting", err)
@@ -76,20 +84,45 @@ func startServer() (func() error, func(err error)) {
 		}
 }
 
-func startScanner() (func() error, func(err error)) {
-	interval := conf.Server.ScanInterval
+var sigChan = make(chan os.Signal, 1)
+
+func startSignaler() (func() error, func(err error)) {
+	scanner := GetScanner()
+	ctx, cancel := context.WithCancel(context.Background())
+
+	return func() error {
+			for {
+				select {
+				case sig := <-sigChan:
+					log.Info(ctx, "Received signal, triggering a new scan", "signal", sig)
+					start := time.Now()
+					err := scanner.RescanAll(ctx, false)
+					if err != nil {
+						log.Error(ctx, "Error scanning", err)
+					}
+					log.Info(ctx, "Triggered scan complete", "elapsed", time.Since(start).Round(100*time.Millisecond))
+				case <-ctx.Done():
+					break
+				}
+			}
+		}, func(err error) {
+			cancel()
+			if err != nil {
+				log.Error("Shutting down Signaler due to error", err)
+			} else {
+				log.Info("Shutting down Signaler")
+			}
+		}
+}
+
+func startScanner(interval time.Duration) (func() error, func(err error)) {
 	log.Info("Starting scanner", "interval", interval.String())
 	scanner := GetScanner()
 	ctx, cancel := context.WithCancel(context.Background())
 
 	return func() error {
-			if interval != 0 {
-				time.Sleep(2 * time.Second) // Wait 2 seconds before the first scan
-				scanner.Run(ctx, interval)
-			} else {
-				log.Warn("Periodic scan is DISABLED", "interval", interval)
-				<-ctx.Done()
-			}
+			time.Sleep(2 * time.Second) // Wait 2 seconds before the first scan
+			scanner.Run(ctx, interval)
 
 			return nil
 		}, func(err error) {

cmd/signaler_unix.go

@@ -0,0 +1,17 @@
+// +build !windows
+// +build !plan9
+
+package cmd
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+func init() {
+	signals := []os.Signal{
+		syscall.SIGUSR1,
+	}
+	signal.Notify(sigChan, signals...)
+}