fix: address race conditions and design issues in PlaylistGenerator

Rename PlaylistInfo.OwnerUserID to OwnerUsername so plugins provide
usernames instead of internal user IDs, with server-side resolution via
FindByUsername. Fix race condition on playlistGenerators map by using
write lock in startPlaylistGenerators and moving map access inside the
lock in unloadPlugin/Stop. Add context and WaitGroup to the orchestrator
for proper cancellation and goroutine tracking. Include owner_id in the
plugin playlist unique index. Use SetTracks instead of direct assignment
to refresh playlist duration/size/song count stats.

db/migrations/20260305051806_add_plugin_playlist_fields.go

@@ -12,15 +12,15 @@ func init() {
 }
 
 func upAddPluginPlaylistFields(ctx context.Context, tx *sql.Tx) error {
-	_, err := tx.ExecContext(ctx, `ALTER TABLE playlist ADD COLUMN plugin_id VARCHAR(255) DEFAULT '';`)
+	_, err := tx.ExecContext(ctx, `ALTER TABLE playlist ADD COLUMN plugin_id VARCHAR(255) NOT NULL DEFAULT '';`)
 	if err != nil {
 		return err
 	}
-	_, err = tx.ExecContext(ctx, `ALTER TABLE playlist ADD COLUMN plugin_playlist_id VARCHAR(255) DEFAULT '';`)
+	_, err = tx.ExecContext(ctx, `ALTER TABLE playlist ADD COLUMN plugin_playlist_id VARCHAR(255) NOT NULL DEFAULT '';`)
 	if err != nil {
 		return err
 	}
-	_, err = tx.ExecContext(ctx, `CREATE UNIQUE INDEX IF NOT EXISTS idx_playlist_plugin ON playlist(plugin_id, plugin_playlist_id) WHERE plugin_id != '';`)
+	_, err = tx.ExecContext(ctx, `CREATE UNIQUE INDEX IF NOT EXISTS idx_playlist_plugin ON playlist(plugin_id, plugin_playlist_id, owner_id) WHERE plugin_id != '';`)
 	return err
 }
 

plugins/capabilities/playlist_generator.go

@@ -32,8 +32,8 @@ type GetPlaylistsResponse struct {
 type PlaylistInfo struct {
 	// ID is the plugin-scoped unique identifier for this playlist.
 	ID string `json:"id"`
-	// OwnerUserID is the Navidrome user ID that owns this playlist.
+	// OwnerUsername is the Navidrome username that owns this playlist.
-	OwnerUserID string `json:"ownerUserId"`
+	OwnerUsername string `json:"ownerUsername"`
 }
 
 // GetPlaylistRequest is the request for GetPlaylist.

plugins/capabilities/playlist_generator.yaml

@@ -79,12 +79,12 @@ components:
                 id:
                     type: string
                     description: ID is the plugin-scoped unique identifier for this playlist.
-                ownerUserId:
+                ownerUsername:
                     type: string
-                    description: OwnerUserID is the Navidrome user ID that owns this playlist.
+                    description: OwnerUsername is the Navidrome username that owns this playlist.
             required:
                 - id
-                - ownerUserId
+                - ownerUsername
         SongRef:
             description: SongRef is a reference to a song with metadata for matching.
             properties:

plugins/manager.go

@@ -185,16 +185,16 @@ func (m *Manager) Start(ctx context.Context) error {
 
 // startPlaylistGenerators starts orchestrators for all plugins with the PlaylistGenerator capability.
 func (m *Manager) startPlaylistGenerators(ctx context.Context) {
-	m.mu.RLock()
+	m.mu.Lock()
-	defer m.mu.RUnlock()
+	defer m.mu.Unlock()
 
 	for name, p := range m.plugins {
 		if !hasCapability(p.capabilities, CapabilityPlaylistGenerator) {
 			continue
 		}
-		orch := newPlaylistGeneratorOrchestrator(name, p, m.ds)
+		orch := newPlaylistGeneratorOrchestrator(name, p, m.ds, ctx)
 		m.playlistGenerators[name] = orch
-		go orch.discoverAndSync(ctx)
+		orch.wg.Go(func() { orch.discoverAndSync(orch.ctx) })
 	}
 }
 
@@ -209,9 +209,12 @@ func (m *Manager) Stop() error {
 	}
 
 	// Stop all playlist generator orchestrators
-	for name, orch := range m.playlistGenerators {
+	m.mu.Lock()
+	orchestrators := m.playlistGenerators
+	m.playlistGenerators = make(map[string]*playlistGeneratorOrchestrator)
+	m.mu.Unlock()
+	for _, orch := range orchestrators {
 		orch.stop()
-		delete(m.playlistGenerators, name)
 	}
 
 	// Stop file watcher
@@ -585,12 +588,15 @@ func (m *Manager) unloadPlugin(name string) error {
 		return fmt.Errorf("plugin %q not found", name)
 	}
 	delete(m.plugins, name)
+
+	// Extract playlist generator orchestrator under lock
+	orch := m.playlistGenerators[name]
+	delete(m.playlistGenerators, name)
 	m.mu.Unlock()
 
-	// Stop playlist generator orchestrator if any
+	// Stop playlist generator orchestrator outside lock
-	if orch, ok := m.playlistGenerators[name]; ok {
+	if orch != nil {
 		orch.stop()
-		delete(m.playlistGenerators, name)
 	}
 
 	// Run cleanup functions

plugins/pdk/go/playlistgenerator/playlistgenerator.go

@@ -49,8 +49,8 @@ type GetPlaylistsResponse struct {
 type PlaylistInfo struct {
 	// ID is the plugin-scoped unique identifier for this playlist.
 	ID string `json:"id"`
-	// OwnerUserID is the Navidrome user ID that owns this playlist.
+	// OwnerUsername is the Navidrome username that owns this playlist.
-	OwnerUserID string `json:"ownerUserId"`
+	OwnerUsername string `json:"ownerUsername"`
 }
 
 // SongRef is a reference to a song with metadata for matching.

plugins/pdk/go/playlistgenerator/playlistgenerator_stub.go

@@ -46,8 +46,8 @@ type GetPlaylistsResponse struct {
 type PlaylistInfo struct {
 	// ID is the plugin-scoped unique identifier for this playlist.
 	ID string `json:"id"`
-	// OwnerUserID is the Navidrome user ID that owns this playlist.
+	// OwnerUsername is the Navidrome username that owns this playlist.
-	OwnerUserID string `json:"ownerUserId"`
+	OwnerUsername string `json:"ownerUsername"`
 }
 
 // SongRef is a reference to a song with metadata for matching.

plugins/pdk/rust/nd-pdk-capabilities/src/playlistgenerator.rs

@@ -71,9 +71,9 @@ pub struct PlaylistInfo {
     /// ID is the plugin-scoped unique identifier for this playlist.
     #[serde(default)]
     pub id: String,
-    /// OwnerUserID is the Navidrome user ID that owns this playlist.
+    /// OwnerUsername is the Navidrome username that owns this playlist.
     #[serde(default)]
-    pub owner_user_id: String,
+    pub owner_username: String,
 }
 /// SongRef is a reference to a song with metadata for matching.
 #[derive(Debug, Clone, Default, Serialize, Deserialize)]

plugins/playlist_generator.go

@@ -3,6 +3,7 @@ package plugins
 import (
 	"context"
 	"fmt"
+	"sync"
 	"time"
 
 	"github.com/navidrome/navidrome/core/matcher"
@@ -33,16 +34,22 @@ type playlistGeneratorOrchestrator struct {
 	plugin         *plugin
 	ds             model.DataStore
 	matcher        *matcher.Matcher
+	ctx            context.Context
+	cancel         context.CancelFunc
+	wg             sync.WaitGroup
 	refreshTimers  map[string]*time.Timer // keyed by playlist DB ID
 	discoveryTimer *time.Timer
 }
 
-func newPlaylistGeneratorOrchestrator(pluginName string, p *plugin, ds model.DataStore) *playlistGeneratorOrchestrator {
+func newPlaylistGeneratorOrchestrator(pluginName string, p *plugin, ds model.DataStore, parentCtx context.Context) *playlistGeneratorOrchestrator {
+	ctx, cancel := context.WithCancel(parentCtx)
 	return &playlistGeneratorOrchestrator{
 		pluginName:    pluginName,
 		plugin:        p,
 		ds:            ds,
 		matcher:       matcher.New(ds),
+		ctx:           ctx,
+		cancel:        cancel,
 		refreshTimers: make(map[string]*time.Timer),
 	}
 }
@@ -58,8 +65,16 @@ func (o *playlistGeneratorOrchestrator) discoverAndSync(ctx context.Context) {
 	}
 
 	for _, info := range resp.Playlists {
-		dbID := id.NewHash(o.pluginName, info.ID, info.OwnerUserID)
+		// Resolve username to user ID
-		o.syncPlaylist(ctx, info, dbID)
+		user, err := o.ds.User(adminContext(ctx)).FindByUsername(info.OwnerUsername)
+		if err != nil {
+			log.Error(ctx, "Failed to resolve playlist owner", "plugin", o.pluginName,
+				"playlistID", info.ID, "username", info.OwnerUsername, err)
+			continue
+		}
+		ownerID := user.ID
+		dbID := id.NewHash(o.pluginName, info.ID, ownerID)
+		o.syncPlaylist(ctx, info, dbID, ownerID)
 	}
 
 	// Schedule re-discovery if RefreshInterval > 0
@@ -69,7 +84,7 @@ func (o *playlistGeneratorOrchestrator) discoverAndSync(ctx context.Context) {
 }
 
 // syncPlaylist calls GetPlaylist, matches tracks, and upserts the playlist in the DB.
-func (o *playlistGeneratorOrchestrator) syncPlaylist(ctx context.Context, info capabilities.PlaylistInfo, dbID string) {
+func (o *playlistGeneratorOrchestrator) syncPlaylist(ctx context.Context, info capabilities.PlaylistInfo, dbID string, ownerID string) {
 	resp, err := callPluginFunction[capabilities.GetPlaylistRequest, capabilities.GetPlaylistResponse](
 		ctx, o.plugin, FuncPlaylistGeneratorGetPlaylist, capabilities.GetPlaylistRequest{ID: info.ID},
 	)
@@ -91,7 +106,7 @@ func (o *playlistGeneratorOrchestrator) syncPlaylist(ctx context.Context, info c
 		ID:               dbID,
 		Name:             resp.Name,
 		Comment:          resp.Description,
-		OwnerID:          info.OwnerUserID,
+		OwnerID:          ownerID,
 		Public:           false,
 		ExternalImageURL: resp.CoverArtURL,
 		PluginID:         o.pluginName,
@@ -108,7 +123,7 @@ func (o *playlistGeneratorOrchestrator) syncPlaylist(ctx context.Context, info c
 			MediaFile:   mf,
 		}
 	}
-	pls.Tracks = tracks
+	pls.SetTracks(tracks)
 
 	// Upsert via repository
 	plsRepo := o.ds.Playlist(ctx)
@@ -118,7 +133,7 @@ func (o *playlistGeneratorOrchestrator) syncPlaylist(ctx context.Context, info c
 	}
 
 	log.Info(ctx, "Synced plugin playlist", "plugin", o.pluginName, "playlistID", info.ID,
-		"name", resp.Name, "tracks", len(matched), "owner", info.OwnerUserID)
+		"name", resp.Name, "tracks", len(matched), "owner", ownerID)
 
 	// Schedule refresh if ValidUntil > 0
 	if resp.ValidUntil > 0 {
@@ -127,17 +142,17 @@ func (o *playlistGeneratorOrchestrator) syncPlaylist(ctx context.Context, info c
 		if delay <= 0 {
 			delay = 1 * time.Second // Already expired, refresh soon
 		}
-		o.schedulePlaylistRefresh(ctx, info, dbID, delay)
+		o.schedulePlaylistRefresh(ctx, info, dbID, ownerID, delay)
 	}
 }
 
-func (o *playlistGeneratorOrchestrator) schedulePlaylistRefresh(_ context.Context, info capabilities.PlaylistInfo, dbID string, delay time.Duration) {
+func (o *playlistGeneratorOrchestrator) schedulePlaylistRefresh(_ context.Context, info capabilities.PlaylistInfo, dbID string, ownerID string, delay time.Duration) {
 	// Cancel existing timer if any
 	if timer, ok := o.refreshTimers[dbID]; ok {
 		timer.Stop()
 	}
 	o.refreshTimers[dbID] = time.AfterFunc(delay, func() {
-		o.syncPlaylist(context.Background(), info, dbID)
+		o.wg.Go(func() { o.syncPlaylist(o.ctx, info, dbID, ownerID) })
 	})
 }
 
@@ -146,16 +161,18 @@ func (o *playlistGeneratorOrchestrator) scheduleDiscovery(_ context.Context, del
 		o.discoveryTimer.Stop()
 	}
 	o.discoveryTimer = time.AfterFunc(delay, func() {
-		o.discoverAndSync(context.Background())
+		o.wg.Go(func() { o.discoverAndSync(o.ctx) })
 	})
 }
 
-// stop cancels all timers.
+// stop cancels the context, stops all timers, and waits for in-flight goroutines.
 func (o *playlistGeneratorOrchestrator) stop() {
+	o.cancel()
 	if o.discoveryTimer != nil {
 		o.discoveryTimer.Stop()
 	}
 	for _, timer := range o.refreshTimers {
 		timer.Stop()
 	}
+	o.wg.Wait()
 }

plugins/plugins_suite_test.go

@@ -133,7 +133,13 @@ func createTestManagerWithPluginsAndMetrics(pluginConfig map[string]map[string]s
 	mockPluginRepo := tests.CreateMockPluginRepo()
 	mockPluginRepo.Permitted = true
 	mockPluginRepo.SetData(enabledPlugins)
-	dataStore := &tests.MockDataStore{MockedPlugin: mockPluginRepo}
+
+	// Pre-seed a mock user repo with a default user so that
+	// PlaylistGenerator's discoverAndSync can resolve usernames.
+	mockUserRepo := tests.CreateMockUserRepo()
+	_ = mockUserRepo.Put(&model.User{ID: "user-1", UserName: "admin"})
+
+	dataStore := &tests.MockDataStore{MockedPlugin: mockPluginRepo, MockedUser: mockUserRepo}
 
 	// Create and start manager
 	manager := &Manager{

plugins/testdata/test-playlist-generator/main.go

@@ -21,16 +21,16 @@ func (t *testPlaylistGenerator) GetPlaylists(_ pg.GetPlaylistsRequest) (pg.GetPl
 		return pg.GetPlaylistsResponse{}, fmt.Errorf("%s", errMsg)
 	}
 
-	// Get the owner user ID from config (defaults to "user-1")
+	// Get the owner username from config (defaults to "admin")
-	ownerID := "user-1"
+	ownerUsername := "admin"
-	if id, ok := pdk.GetConfig("owner_id"); ok && id != "" {
+	if u, ok := pdk.GetConfig("owner_username"); ok && u != "" {
-		ownerID = id
+		ownerUsername = u
 	}
 
 	return pg.GetPlaylistsResponse{
 		Playlists: []pg.PlaylistInfo{
-			{ID: "daily-mix-1", OwnerUserID: ownerID},
+			{ID: "daily-mix-1", OwnerUsername: ownerUsername},
-			{ID: "daily-mix-2", OwnerUserID: ownerID},
+			{ID: "daily-mix-2", OwnerUsername: ownerUsername},
 		},
 		RefreshInterval: 0, // No re-discovery in tests
 	}, nil