refactor(config): make the artwork tuning options dev flags

ArtworkWorkerConcurrency and ArtworkExternalMaxRPS become
DevArtworkWorkerConcurrency and DevArtworkExternalMaxRPS, joining the
other DevArtwork* flags. Their defaults should not need tuning, so they
do not belong in the documented, user-facing option set.

conf/configuration.go

@@ -62,8 +62,6 @@ type configOptions struct {
 	ImageCacheSize                  string
 	AlbumPlayCountMode              string
 	EnableArtworkPrecache           bool
-	ArtworkWorkerConcurrency        int
-	ArtworkExternalMaxRPS           int
 	AutoImportPlaylists             bool
 	DefaultPlaylistPublicVisibility bool
 	PlaylistsPath                   string
@@ -146,6 +144,8 @@ type configOptions struct {
 	DevArtworkThrottleBacklogLimit    int
 	DevArtworkThrottleBacklogTimeout  time.Duration
 	DevArtworkThrottleBuffered        bool
+	DevArtworkWorkerConcurrency       int
+	DevArtworkExternalMaxRPS          int
 	DevArtistInfoTimeToLive           time.Duration
 	DevAlbumInfoTimeToLive            time.Duration
 	DevExternalScanner                bool
@@ -1075,10 +1075,10 @@ func setViperDefaults() {
 	viper.SetDefault("devartworkthrottlebuffered", true)
 	// Half the CPU count (min 2), so local resolution scales with the host but stays under the
 	// SQLite pool (MaxOpenConns) — leaving connections for the scanner, scrobbles and the UI.
-	viper.SetDefault("artworkworkerconcurrency", max(2, runtime.NumCPU()/2))
+	viper.SetDefault("devartworkworkerconcurrency", max(2, runtime.NumCPU()/2))
 	// External RPS gates outbound calls to third-party services (per service); it is bounded by
 	// their tolerance, not the host, so it stays a small constant regardless of CPU count.
-	viper.SetDefault("artworkexternalmaxrps", 2)
+	viper.SetDefault("devartworkexternalmaxrps", 2)
 	viper.SetDefault("devartistinfotimetolive", consts.ArtistInfoTimeToLive)
 	viper.SetDefault("devalbuminfotimetolive", consts.AlbumInfoTimeToLive)
 	viper.SetDefault("devexternalscanner", true)

core/artwork/e2e/acquire_serve_test.go

@@ -65,7 +65,7 @@ var _ = Describe("Acquisition → serve loop", func() {
 		conf.Server.CoverArtPriority = "cover.jpg"
 		conf.Server.ArtistArtPriority = "artist.png" // keeps artist resolution offline
 		conf.Server.EnableMediaFileCoverArt = true
-		conf.Server.ArtworkWorkerConcurrency = 1
+		conf.Server.DevArtworkWorkerConcurrency = 1
 
 		folderRepo = &fakeFolderRepo{}
 		libRepo = &tests.MockLibraryRepo{}

core/artwork/e2e/resolution_harness_test.go

@@ -90,7 +90,7 @@ func setupResolutionHarness() {
 	conf.Server.ImageCacheSize = "0"
 	conf.Server.EnableExternalServices = false
 	conf.Server.EnableMediaFileCoverArt = true
-	conf.Server.ArtworkWorkerConcurrency = 1
+	conf.Server.DevArtworkWorkerConcurrency = 1
 
 	rctx = request.WithUser(GinkgoT().Context(), model.User{ID: "admin-1", UserName: "admin", IsAdmin: true})
 	harness.TruncateDB(userTables)

core/artwork/gate.go

@@ -67,7 +67,7 @@ func (w *Worker) gateFor(name string) *extGate {
 	if g, ok := w.gates[name]; ok {
 		return g
 	}
-	rps := conf.Server.ArtworkExternalMaxRPS
+	rps := conf.Server.DevArtworkExternalMaxRPS
 	limit := rate.Inf
 	if rps > 0 {
 		limit = rate.Limit(rps)

core/artwork/worker.go

@@ -71,9 +71,9 @@ func NewWorker(ds model.DataStore, store *ImageStore, ag *agents.Agents, ffmpeg
 // rate-limit permit, so a sleeping lookup would crowd out a cover sitting on disk.
 func newDrainPools() []*drainPool {
 	budget := conf.MaxOpenConns() // floored at 4, so both remainders below stay positive
-	local := min(max(1, conf.Server.ArtworkWorkerConcurrency), budget-1)
+	local := min(max(1, conf.Server.DevArtworkWorkerConcurrency), budget-1)
 	// More external slots than the rate allows would only sleep in the limiter.
-	external := min(max(2, 2*conf.Server.ArtworkExternalMaxRPS), budget-local)
+	external := min(max(2, 2*conf.Server.DevArtworkExternalMaxRPS), budget-local)
 	return []*drainPool{
 		{name: "local", kinds: localDrainKinds, concurrency: local, wake: make(chan struct{}, 1)},
 		{name: "external", kinds: externalDrainKinds, concurrency: external, wake: make(chan struct{}, 1)},

core/artwork/worker_test.go

@@ -145,7 +145,7 @@ var _ = Describe("Worker", func() {
 		ds.MockedAlbum = tests.CreateMockAlbumRepo()
 		store = NewImageStore(GinkgoT().TempDir())
 		conf.Server.CoverArtPriority = "cover.jpg, embedded"
-		conf.Server.ArtworkExternalMaxRPS = 1000 // keep the limiter out of the way of behavior tests
+		conf.Server.DevArtworkExternalMaxRPS = 1000 // keep the limiter out of the way of behavior tests
 		broker = &fakeEventBroker{}
 		imgCache = &recordingCache{FileCache: cache.NewFileCache("WorkerTest", "100MB", "images", 0,
 			func(ctx context.Context, arg cache.Item) (io.Reader, error) {

server/subsonic/e2e/subsonic_artwork_test.go

@@ -93,7 +93,7 @@ var _ = Describe("Artwork Serving", Ordered, func() {
 		conf.Server.CoverArtPriority = "cover.jpg"
 		conf.Server.ArtistArtPriority = "artist.png" // offline: artists resolve absent, out of scope here
 		conf.Server.EnableMediaFileCoverArt = false
-		conf.Server.ArtworkWorkerConcurrency = 1
+		conf.Server.DevArtworkWorkerConcurrency = 1
 		conf.Server.CacheFolder = conf.NewDir(GinkgoT().TempDir())
 		conf.Server.EnableSharing = true
 		conf.Server.DevArtworkMaxRequests = 100