update

core/agents/agents.go

@@ -0,0 +1,374 @@
+package agents
+
+import (
+	"context"
+	"slices"
+	"strings"
+	"time"
+
+	"github.com/navidrome/navidrome/conf"
+	"github.com/navidrome/navidrome/consts"
+	"github.com/navidrome/navidrome/log"
+	"github.com/navidrome/navidrome/model"
+	"github.com/navidrome/navidrome/utils"
+	"github.com/navidrome/navidrome/utils/singleton"
+)
+
+// PluginLoader defines an interface for loading plugins
+type PluginLoader interface {
+	// PluginNames returns the names of all plugins that implement a particular service
+	PluginNames(capability string) []string
+	// LoadMediaAgent loads and returns a media agent plugin
+	LoadMediaAgent(name string) (Interface, bool)
+}
+
+type Agents struct {
+	ds           model.DataStore
+	pluginLoader PluginLoader
+}
+
+// GetAgents returns the singleton instance of Agents
+func GetAgents(ds model.DataStore, pluginLoader PluginLoader) *Agents {
+	return singleton.GetInstance(func() *Agents {
+		return createAgents(ds, pluginLoader)
+	})
+}
+
+// createAgents creates a new Agents instance. Used in tests
+func createAgents(ds model.DataStore, pluginLoader PluginLoader) *Agents {
+	return &Agents{
+		ds:           ds,
+		pluginLoader: pluginLoader,
+	}
+}
+
+// enabledAgent represents an enabled agent with its type information
+type enabledAgent struct {
+	name     string
+	isPlugin bool
+}
+
+// getEnabledAgentNames returns the current list of enabled agents, including:
+// 1. Built-in agents and plugins from config (in the specified order)
+// 2. Always include LocalAgentName
+// 3. If config is empty, include ONLY LocalAgentName
+// Each enabledAgent contains the name and whether it's a plugin (true) or built-in (false)
+func (a *Agents) getEnabledAgentNames() []enabledAgent {
+	// If no agents configured, ONLY use the local agent
+	if conf.Server.Agents == "" {
+		return []enabledAgent{{name: LocalAgentName, isPlugin: false}}
+	}
+
+	// Get all available plugin names
+	var availablePlugins []string
+	if a.pluginLoader != nil {
+		availablePlugins = a.pluginLoader.PluginNames("MetadataAgent")
+	}
+
+	configuredAgents := strings.Split(conf.Server.Agents, ",")
+
+	// Always add LocalAgentName if not already included
+	hasLocalAgent := slices.Contains(configuredAgents, LocalAgentName)
+	if !hasLocalAgent {
+		configuredAgents = append(configuredAgents, LocalAgentName)
+	}
+
+	// Filter to only include valid agents (built-in or plugins)
+	var validAgents []enabledAgent
+	for _, name := range configuredAgents {
+		// Check if it's a built-in agent
+		isBuiltIn := Map[name] != nil
+
+		// Check if it's a plugin
+		isPlugin := slices.Contains(availablePlugins, name)
+
+		if isBuiltIn {
+			validAgents = append(validAgents, enabledAgent{name: name, isPlugin: false})
+		} else if isPlugin {
+			validAgents = append(validAgents, enabledAgent{name: name, isPlugin: true})
+		} else {
+			log.Debug("Unknown agent ignored", "name", name)
+		}
+	}
+	return validAgents
+}
+
+func (a *Agents) getAgent(ea enabledAgent) Interface {
+	if ea.isPlugin {
+		// Try to load WASM plugin agent (if plugin loader is available)
+		if a.pluginLoader != nil {
+			agent, ok := a.pluginLoader.LoadMediaAgent(ea.name)
+			if ok && agent != nil {
+				return agent
+			}
+		}
+	} else {
+		// Try to get built-in agent
+		constructor, ok := Map[ea.name]
+		if ok {
+			agent := constructor(a.ds)
+			if agent != nil {
+				return agent
+			}
+			log.Debug("Built-in agent not available. Missing configuration?", "name", ea.name)
+		}
+	}
+
+	return nil
+}
+
+func (a *Agents) AgentName() string {
+	return "agents"
+}
+
+func (a *Agents) GetArtistMBID(ctx context.Context, id string, name string) (string, error) {
+	switch id {
+	case consts.UnknownArtistID:
+		return "", ErrNotFound
+	case consts.VariousArtistsID:
+		return "", nil
+	}
+	start := time.Now()
+	for _, enabledAgent := range a.getEnabledAgentNames() {
+		ag := a.getAgent(enabledAgent)
+		if ag == nil {
+			continue
+		}
+		if utils.IsCtxDone(ctx) {
+			break
+		}
+		retriever, ok := ag.(ArtistMBIDRetriever)
+		if !ok {
+			continue
+		}
+		mbid, err := retriever.GetArtistMBID(ctx, id, name)
+		if mbid != "" && err == nil {
+			log.Debug(ctx, "Got MBID", "agent", ag.AgentName(), "artist", name, "mbid", mbid, "elapsed", time.Since(start))
+			return mbid, nil
+		}
+	}
+	return "", ErrNotFound
+}
+
+func (a *Agents) GetArtistURL(ctx context.Context, id, name, mbid string) (string, error) {
+	switch id {
+	case consts.UnknownArtistID:
+		return "", ErrNotFound
+	case consts.VariousArtistsID:
+		return "", nil
+	}
+	start := time.Now()
+	for _, enabledAgent := range a.getEnabledAgentNames() {
+		ag := a.getAgent(enabledAgent)
+		if ag == nil {
+			continue
+		}
+		if utils.IsCtxDone(ctx) {
+			break
+		}
+		retriever, ok := ag.(ArtistURLRetriever)
+		if !ok {
+			continue
+		}
+		url, err := retriever.GetArtistURL(ctx, id, name, mbid)
+		if url != "" && err == nil {
+			log.Debug(ctx, "Got External Url", "agent", ag.AgentName(), "artist", name, "url", url, "elapsed", time.Since(start))
+			return url, nil
+		}
+	}
+	return "", ErrNotFound
+}
+
+func (a *Agents) GetArtistBiography(ctx context.Context, id, name, mbid string) (string, error) {
+	switch id {
+	case consts.UnknownArtistID:
+		return "", ErrNotFound
+	case consts.VariousArtistsID:
+		return "", nil
+	}
+	start := time.Now()
+	for _, enabledAgent := range a.getEnabledAgentNames() {
+		ag := a.getAgent(enabledAgent)
+		if ag == nil {
+			continue
+		}
+		if utils.IsCtxDone(ctx) {
+			break
+		}
+		retriever, ok := ag.(ArtistBiographyRetriever)
+		if !ok {
+			continue
+		}
+		bio, err := retriever.GetArtistBiography(ctx, id, name, mbid)
+		if err == nil {
+			log.Debug(ctx, "Got Biography", "agent", ag.AgentName(), "artist", name, "len", len(bio), "elapsed", time.Since(start))
+			return bio, nil
+		}
+	}
+	return "", ErrNotFound
+}
+
+// GetSimilarArtists returns similar artists by id, name, and/or mbid. Because some artists returned from an enabled
+// agent may not exist in the database, return at most limit * conf.Server.DevExternalArtistFetchMultiplier items.
+func (a *Agents) GetSimilarArtists(ctx context.Context, id, name, mbid string, limit int) ([]Artist, error) {
+	switch id {
+	case consts.UnknownArtistID:
+		return nil, ErrNotFound
+	case consts.VariousArtistsID:
+		return nil, nil
+	}
+
+	overLimit := int(float64(limit) * conf.Server.DevExternalArtistFetchMultiplier)
+
+	start := time.Now()
+	for _, enabledAgent := range a.getEnabledAgentNames() {
+		ag := a.getAgent(enabledAgent)
+		if ag == nil {
+			continue
+		}
+		if utils.IsCtxDone(ctx) {
+			break
+		}
+		retriever, ok := ag.(ArtistSimilarRetriever)
+		if !ok {
+			continue
+		}
+		similar, err := retriever.GetSimilarArtists(ctx, id, name, mbid, overLimit)
+		if len(similar) > 0 && err == nil {
+			if log.IsGreaterOrEqualTo(log.LevelTrace) {
+				log.Debug(ctx, "Got Similar Artists", "agent", ag.AgentName(), "artist", name, "similar", similar, "elapsed", time.Since(start))
+			} else {
+				log.Debug(ctx, "Got Similar Artists", "agent", ag.AgentName(), "artist", name, "similarReceived", len(similar), "elapsed", time.Since(start))
+			}
+			return similar, err
+		}
+	}
+	return nil, ErrNotFound
+}
+
+func (a *Agents) GetArtistImages(ctx context.Context, id, name, mbid string) ([]ExternalImage, error) {
+	switch id {
+	case consts.UnknownArtistID:
+		return nil, ErrNotFound
+	case consts.VariousArtistsID:
+		return nil, nil
+	}
+	start := time.Now()
+	for _, enabledAgent := range a.getEnabledAgentNames() {
+		ag := a.getAgent(enabledAgent)
+		if ag == nil {
+			continue
+		}
+		if utils.IsCtxDone(ctx) {
+			break
+		}
+		retriever, ok := ag.(ArtistImageRetriever)
+		if !ok {
+			continue
+		}
+		images, err := retriever.GetArtistImages(ctx, id, name, mbid)
+		if len(images) > 0 && err == nil {
+			log.Debug(ctx, "Got Images", "agent", ag.AgentName(), "artist", name, "images", images, "elapsed", time.Since(start))
+			return images, nil
+		}
+	}
+	return nil, ErrNotFound
+}
+
+// GetArtistTopSongs returns top songs by id, name, and/or mbid. Because some songs returned from an enabled
+// agent may not exist in the database, return at most limit * conf.Server.DevExternalArtistFetchMultiplier items.
+func (a *Agents) GetArtistTopSongs(ctx context.Context, id, artistName, mbid string, count int) ([]Song, error) {
+	switch id {
+	case consts.UnknownArtistID:
+		return nil, ErrNotFound
+	case consts.VariousArtistsID:
+		return nil, nil
+	}
+
+	overLimit := int(float64(count) * conf.Server.DevExternalArtistFetchMultiplier)
+
+	start := time.Now()
+	for _, enabledAgent := range a.getEnabledAgentNames() {
+		ag := a.getAgent(enabledAgent)
+		if ag == nil {
+			continue
+		}
+		if utils.IsCtxDone(ctx) {
+			break
+		}
+		retriever, ok := ag.(ArtistTopSongsRetriever)
+		if !ok {
+			continue
+		}
+		songs, err := retriever.GetArtistTopSongs(ctx, id, artistName, mbid, overLimit)
+		if len(songs) > 0 && err == nil {
+			log.Debug(ctx, "Got Top Songs", "agent", ag.AgentName(), "artist", artistName, "songs", songs, "elapsed", time.Since(start))
+			return songs, nil
+		}
+	}
+	return nil, ErrNotFound
+}
+
+func (a *Agents) GetAlbumInfo(ctx context.Context, name, artist, mbid string) (*AlbumInfo, error) {
+	if name == consts.UnknownAlbum {
+		return nil, ErrNotFound
+	}
+	start := time.Now()
+	for _, enabledAgent := range a.getEnabledAgentNames() {
+		ag := a.getAgent(enabledAgent)
+		if ag == nil {
+			continue
+		}
+		if utils.IsCtxDone(ctx) {
+			break
+		}
+		retriever, ok := ag.(AlbumInfoRetriever)
+		if !ok {
+			continue
+		}
+		album, err := retriever.GetAlbumInfo(ctx, name, artist, mbid)
+		if err == nil {
+			log.Debug(ctx, "Got Album Info", "agent", ag.AgentName(), "album", name, "artist", artist,
+				"mbid", mbid, "elapsed", time.Since(start))
+			return album, nil
+		}
+	}
+	return nil, ErrNotFound
+}
+
+func (a *Agents) GetAlbumImages(ctx context.Context, name, artist, mbid string) ([]ExternalImage, error) {
+	if name == consts.UnknownAlbum {
+		return nil, ErrNotFound
+	}
+	start := time.Now()
+	for _, enabledAgent := range a.getEnabledAgentNames() {
+		ag := a.getAgent(enabledAgent)
+		if ag == nil {
+			continue
+		}
+		if utils.IsCtxDone(ctx) {
+			break
+		}
+		retriever, ok := ag.(AlbumImageRetriever)
+		if !ok {
+			continue
+		}
+		images, err := retriever.GetAlbumImages(ctx, name, artist, mbid)
+		if len(images) > 0 && err == nil {
+			log.Debug(ctx, "Got Album Images", "agent", ag.AgentName(), "album", name, "artist", artist,
+				"mbid", mbid, "elapsed", time.Since(start))
+			return images, nil
+		}
+	}
+	return nil, ErrNotFound
+}
+
+var _ Interface = (*Agents)(nil)
+var _ ArtistMBIDRetriever = (*Agents)(nil)
+var _ ArtistURLRetriever = (*Agents)(nil)
+var _ ArtistBiographyRetriever = (*Agents)(nil)
+var _ ArtistSimilarRetriever = (*Agents)(nil)
+var _ ArtistImageRetriever = (*Agents)(nil)
+var _ ArtistTopSongsRetriever = (*Agents)(nil)
+var _ AlbumInfoRetriever = (*Agents)(nil)
+var _ AlbumImageRetriever = (*Agents)(nil)