Use singleton in other places as well

cmd/root.go

@@ -10,6 +10,7 @@ import (
 	"github.com/navidrome/navidrome/consts"
 	"github.com/navidrome/navidrome/db"
 	"github.com/navidrome/navidrome/log"
+	"github.com/navidrome/navidrome/scheduler"
 	"github.com/oklog/run"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
@@ -121,10 +122,10 @@ func startSignaler() (func() error, func(err error)) {
 
 func schedulePeriodicScan(schedule string) {
 	scanner := GetScanner()
-	scheduler := GetScheduler()
+	schedulerInstance := scheduler.GetInstance()
 
 	log.Info("Scheduling periodic scan", "schedule", schedule)
-	err := scheduler.Add(schedule, func() {
+	err := schedulerInstance.Add(schedule, func() {
 		_ = scanner.RescanAll(context.Background(), false)
 	})
 	if err != nil {
@@ -140,11 +141,11 @@ func schedulePeriodicScan(schedule string) {
 
 func startScheduler() (func() error, func(err error)) {
 	log.Info("Starting scheduler")
-	scheduler := GetScheduler()
+	schedulerInstance := scheduler.GetInstance()
 	ctx, cancel := context.WithCancel(context.Background())
 
 	return func() error {
-			scheduler.Run(ctx)
+			schedulerInstance.Run(ctx)
 
 			return nil
 		}, func(err error) {

cmd/wire_gen.go

@@ -13,7 +13,6 @@ import (
 	"github.com/navidrome/navidrome/core/transcoder"
 	"github.com/navidrome/navidrome/persistence"
 	"github.com/navidrome/navidrome/scanner"
-	"github.com/navidrome/navidrome/scheduler"
 	"github.com/navidrome/navidrome/server"
 	"github.com/navidrome/navidrome/server/events"
 	"github.com/navidrome/navidrome/server/nativeapi"
@@ -31,7 +30,7 @@ func CreateServer(musicFolder string) *server.Server {
 
 func CreateNativeAPIRouter() *nativeapi.Router {
 	dataStore := persistence.New()
-	broker := GetBroker()
+	broker := events.GetBroker()
 	share := core.NewShare(dataStore)
 	router := nativeapi.New(dataStore, broker, share)
 	return router
@@ -48,8 +47,8 @@ func CreateSubsonicAPIRouter() *subsonic.Router {
 	players := core.NewPlayers(dataStore)
 	externalMetadata := core.NewExternalMetadata(dataStore)
 	scanner := GetScanner()
-	broker := GetBroker()
-	scrobblerScrobbler := scrobbler.New(dataStore)
+	broker := events.GetBroker()
+	scrobblerScrobbler := scrobbler.GetInstance(dataStore)
 	router := subsonic.New(dataStore, artwork, mediaStreamer, archiver, players, externalMetadata, scanner, broker, scrobblerScrobbler)
 	return router
 }
@@ -65,24 +64,14 @@ func createScanner() scanner.Scanner {
 	artworkCache := core.GetImageCache()
 	artwork := core.NewArtwork(dataStore, artworkCache)
 	cacheWarmer := core.NewCacheWarmer(artwork, artworkCache)
-	broker := GetBroker()
+	broker := events.GetBroker()
 	scannerScanner := scanner.New(dataStore, cacheWarmer, broker)
 	return scannerScanner
 }
 
-func createBroker() events.Broker {
-	broker := events.NewBroker()
-	return broker
-}
-
-func createScheduler() scheduler.Scheduler {
-	schedulerScheduler := scheduler.New()
-	return schedulerScheduler
-}
-
 // wire_injectors.go:
 
-var allProviders = wire.NewSet(core.Set, subsonic.New, nativeapi.New, persistence.New, lastfm.NewRouter, GetBroker)
+var allProviders = wire.NewSet(core.Set, subsonic.New, nativeapi.New, persistence.New, lastfm.NewRouter, events.GetBroker)
 
 // Scanner must be a Singleton
 var (
@@ -96,29 +85,3 @@ func GetScanner() scanner.Scanner {
 	})
 	return scannerInstance
 }
-
-// Broker must be a Singleton
-var (
-	onceBroker     sync.Once
-	brokerInstance events.Broker
-)
-
-func GetBroker() events.Broker {
-	onceBroker.Do(func() {
-		brokerInstance = createBroker()
-	})
-	return brokerInstance
-}
-
-// Scheduler must be a Singleton
-var (
-	onceScheduler     sync.Once
-	schedulerInstance scheduler.Scheduler
-)
-
-func GetScheduler() scheduler.Scheduler {
-	onceScheduler.Do(func() {
-		schedulerInstance = createScheduler()
-	})
-	return schedulerInstance
-}

cmd/wire_injectors.go

@@ -5,14 +5,14 @@ package cmd
 import (
 	"sync"
 
+	"github.com/navidrome/navidrome/server/events"
+
 	"github.com/google/wire"
 	"github.com/navidrome/navidrome/core"
 	"github.com/navidrome/navidrome/core/agents/lastfm"
 	"github.com/navidrome/navidrome/persistence"
 	"github.com/navidrome/navidrome/scanner"
-	"github.com/navidrome/navidrome/scheduler"
 	"github.com/navidrome/navidrome/server"
-	"github.com/navidrome/navidrome/server/events"
 	"github.com/navidrome/navidrome/server/nativeapi"
 	"github.com/navidrome/navidrome/server/subsonic"
 )
@@ -23,7 +23,7 @@ var allProviders = wire.NewSet(
 	nativeapi.New,
 	persistence.New,
 	lastfm.NewRouter,
-	GetBroker,
+	events.GetBroker,
 )
 
 func CreateServer(musicFolder string) *server.Server {
@@ -71,41 +71,3 @@ func createScanner() scanner.Scanner {
 		scanner.New,
 	))
 }
-
-// Broker must be a Singleton
-var (
-	onceBroker     sync.Once
-	brokerInstance events.Broker
-)
-
-func GetBroker() events.Broker {
-	onceBroker.Do(func() {
-		brokerInstance = createBroker()
-	})
-	return brokerInstance
-}
-
-func createBroker() events.Broker {
-	panic(wire.Build(
-		events.NewBroker,
-	))
-}
-
-// Scheduler must be a Singleton
-var (
-	onceScheduler     sync.Once
-	schedulerInstance scheduler.Scheduler
-)
-
-func GetScheduler() scheduler.Scheduler {
-	onceScheduler.Do(func() {
-		schedulerInstance = createScheduler()
-	})
-	return schedulerInstance
-}
-
-func createScheduler() scheduler.Scheduler {
-	panic(wire.Build(
-		scheduler.New,
-	))
-}

core/scrobbler/scrobbler.go

@@ -32,7 +32,7 @@ type scrobbler struct {
 	playMap *ttlcache.Cache
 }
 
-func New(ds model.DataStore) Scrobbler {
+func GetInstance(ds model.DataStore) Scrobbler {
 	instance := singleton.Get(scrobbler{}, func() interface{} {
 		m := ttlcache.NewCache()
 		m.SkipTTLExtensionOnHit(true)

core/wire_providers.go

@@ -16,6 +16,6 @@ var Set = wire.NewSet(
 	NewCacheWarmer,
 	NewPlayers,
 	transcoder.New,
-	scrobbler.New,
+	scrobbler.GetInstance,
 	NewShare,
 )

scheduler/scheduler.go

@@ -3,6 +3,7 @@ package scheduler
 import (
 	"context"
 
+	"github.com/navidrome/navidrome/utils/singleton"
 	"github.com/robfig/cron/v3"
 )
 
@@ -11,11 +12,14 @@ type Scheduler interface {
 	Add(crontab string, cmd func()) error
 }
 
-func New() Scheduler {
+func GetInstance() Scheduler {
+	instance := singleton.Get(&scheduler{}, func() interface{} {
 		c := cron.New(cron.WithLogger(&logger{}))
 		return &scheduler{
 			c: c,
 		}
+	})
+	return instance.(*scheduler)
 }
 
 type scheduler struct {

server/events/sse.go

@@ -10,6 +10,8 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/navidrome/navidrome/utils/singleton"
+
 	"code.cloudfoundry.org/go-diodes"
 	"github.com/google/uuid"
 	"github.com/navidrome/navidrome/consts"
@@ -69,7 +71,8 @@ type broker struct {
 	unsubscribing clientsChan
 }
 
-func NewBroker() Broker {
+func GetBroker() Broker {
+	instance := singleton.Get(&broker{}, func() interface{} {
 		// Instantiate a broker
 		broker := &broker{
 			publish:       make(messageChan, 100),
@@ -79,8 +82,10 @@ func NewBroker() Broker {
 
 		// Set it running - listening and broadcasting events
 		go broker.listen()
-
 		return broker
+	})
+
+	return instance.(*broker)
 }
 
 func (b *broker) SendMessage(ctx context.Context, evt Event) {