navidrome/plugins/lyrics_adapter.go
Deluan Quintão 756df9decf
fix: dedupe and cap concurrent lyrics plugin fetches (#5792)
* fix: dedupe and cap concurrent lyrics plugin fetches

Clients like Finamp prefetch lyrics for several queue tracks at once. The
resulting burst of concurrent plugin calls can rate-limit the primary
lyrics provider into a timeout, making the plugin fall back to a lower
quality source and cache the bad result.

SimpleCache.GetWithLoader now deduplicates concurrent loads of the same
key via singleflight, with every waiter receiving the winner's result or
error. The Jellyfin lyrics loader is detached from the request context so
one cancelled request cannot fail the load for all waiters, and the
lyrics adapter caps in-flight plugin calls at 2 per plugin, queueing the
rest. As a side effect, the cached HTTP client used by the Last.fm,
Deezer and ListenBrainz agents also collapses identical concurrent
requests into a single upstream call.

* fix: harden lyrics concurrency fixes per review

Replace the stringified singleflight keys with a per-cache flight map
keyed by the cache key type itself, eliminating potential key collisions
for non-string keys, the nil-interface assertion panic, and the
stringification overhead. Release the lyrics semaphore slot via defer so
a panicking plugin call cannot leak it, and bound the detached lyrics
load with a one-minute timeout so a hung plugin cannot pin its
singleflight and semaphore slot indefinitely.
2026-07-16 20:10:35 -04:00

80 lines
2.0 KiB
Go

package plugins
import (
"context"
"github.com/navidrome/navidrome/log"
"github.com/navidrome/navidrome/model"
"github.com/navidrome/navidrome/plugins/capabilities"
)
const CapabilityLyrics Capability = "Lyrics"
const (
FuncLyricsGetLyrics = "nd_lyrics_get_lyrics"
)
// maxConcurrentLyricsCalls caps in-flight lyrics calls per plugin: clients prefetch
// lyrics for whole queues, and the resulting burst can rate-limit upstream providers.
const maxConcurrentLyricsCalls = 2
func init() {
registerCapability(
CapabilityLyrics,
FuncLyricsGetLyrics,
)
}
func newLyricsPlugin(p *plugin) *LyricsPlugin {
return &LyricsPlugin{name: p.name, plugin: p}
}
// LyricsPlugin adapts a WASM plugin with the Lyrics capability.
type LyricsPlugin struct {
name string
plugin *plugin
}
// GetLyrics calls the plugin to fetch lyrics, then content-sniffs each response
// via model.ParseLyrics (TTML/SRT/YAML/LRC/plain).
func (l *LyricsPlugin) GetLyrics(ctx context.Context, mf *model.MediaFile) (model.LyricList, error) {
select {
case l.plugin.lyricsSem <- struct{}{}:
defer func() { <-l.plugin.lyricsSem }()
case <-ctx.Done():
return nil, ctx.Err()
}
req := capabilities.GetLyricsRequest{
Track: mediaFileToTrackInfo(l.plugin, mf),
}
resp, err := callPluginFunction[capabilities.GetLyricsRequest, capabilities.GetLyricsResponse](
ctx, l.plugin, FuncLyricsGetLyrics, req,
)
if err != nil {
return nil, err
}
// The lyric text comes from the plugin, not the media file's own tags, so
// attribute logs to both the plugin and the track it was fetched for.
ctx = log.NewContext(ctx, "plugin", l.name, "file", mf.Path)
var result model.LyricList
for _, lt := range resp.Lyrics {
lang := lt.Lang
if lang == "" {
lang = "xxx"
}
parsed, err := model.ParseLyrics(ctx, "", lang, []byte(lt.Text))
if err != nil {
log.Warn(ctx, "Error parsing plugin lyrics", err)
continue
}
for _, lyric := range parsed {
if !lyric.IsEmpty() {
result = append(result, lyric)
}
}
}
return result, nil
}