navidrome/plugins/lyrics_adapter_test.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

167 lines
5.1 KiB
Go

//go:build !windows
package plugins
import (
"context"
"github.com/navidrome/navidrome/model"
. "github.com/onsi/ginkgo/v2"
. "github.com/onsi/gomega"
)
var _ = Describe("LyricsPlugin", Ordered, func() {
var (
lyricsManager *Manager
provider *LyricsPlugin
)
BeforeAll(func() {
lyricsManager, _ = createTestManagerWithPlugins(nil,
"test-lyrics"+PackageExtension,
"test-metadata-agent"+PackageExtension,
)
p, ok := lyricsManager.LoadLyricsProvider("test-lyrics")
Expect(ok).To(BeTrue())
provider = p.(*LyricsPlugin)
})
Describe("LoadLyricsProvider", func() {
It("returns a lyrics provider for a plugin with Lyrics capability", func() {
Expect(provider).ToNot(BeNil())
})
It("returns false for a plugin without Lyrics capability", func() {
_, ok := lyricsManager.LoadLyricsProvider("test-metadata-agent")
Expect(ok).To(BeFalse())
})
It("returns false for non-existent plugin", func() {
_, ok := lyricsManager.LoadLyricsProvider("non-existent")
Expect(ok).To(BeFalse())
})
})
Describe("GetLyrics", func() {
It("successfully returns lyrics from the plugin", func() {
track := &model.MediaFile{
ID: "track-1",
Title: "Test Song",
Artist: "Test Artist",
}
result, err := provider.GetLyrics(GinkgoT().Context(), track)
Expect(err).ToNot(HaveOccurred())
Expect(result).To(HaveLen(1))
Expect(result[0].Line).ToNot(BeEmpty())
Expect(result[0].Line[0].Value).To(ContainSubstring("Test Song"))
})
It("defaults language to 'xxx' when plugin does not provide one", func() {
manager, _ := createTestManagerWithPlugins(map[string]map[string]string{
"test-lyrics": {"no_lang": "true"},
}, "test-lyrics"+PackageExtension)
p, ok := manager.LoadLyricsProvider("test-lyrics")
Expect(ok).To(BeTrue())
track := &model.MediaFile{ID: "track-1", Title: "Test Song", Artist: "Test Artist"}
result, err := p.GetLyrics(GinkgoT().Context(), track)
Expect(err).ToNot(HaveOccurred())
Expect(result).To(HaveLen(1))
Expect(result[0].Lang).To(Equal("xxx"))
})
It("blocks new calls while the per-plugin concurrency cap is saturated", func() {
sem := provider.plugin.lyricsSem
for range cap(sem) {
sem <- struct{}{}
}
ctx := GinkgoT().Context()
track := &model.MediaFile{ID: "track-1", Title: "Test Song", Artist: "Test Artist"}
done := make(chan error, 1)
go func() {
_, err := provider.GetLyrics(ctx, track)
done <- err
}()
Consistently(done, "500ms").ShouldNot(Receive())
<-sem // free one slot; the pending call should now proceed
Eventually(done).Should(Receive(BeNil()))
for range cap(sem) - 1 {
<-sem
}
})
It("gives up waiting for a slot when the context is cancelled", func() {
sem := provider.plugin.lyricsSem
for range cap(sem) {
sem <- struct{}{}
}
defer func() {
for range cap(sem) {
<-sem
}
}()
ctx, cancel := context.WithCancel(GinkgoT().Context())
cancel()
_, err := provider.GetLyrics(ctx, &model.MediaFile{ID: "track-1"})
Expect(err).To(MatchError(context.Canceled))
})
It("returns error when plugin returns error", func() {
manager, _ := createTestManagerWithPlugins(map[string]map[string]string{
"test-lyrics": {"error": "service unavailable"},
}, "test-lyrics"+PackageExtension)
p, ok := manager.LoadLyricsProvider("test-lyrics")
Expect(ok).To(BeTrue())
track := &model.MediaFile{ID: "track-1", Title: "Test Song"}
_, err := p.GetLyrics(GinkgoT().Context(), track)
Expect(err).To(HaveOccurred())
})
// Each DescribeTable entry proves that the adapter's content-sniffing routes
// the plugin's rich payload to the right parser rather than mangling it as plain text.
DescribeTable("content-sniffs plugin responses across all supported formats",
func(format string, wantSynced bool, wantLine string) {
manager, _ := createTestManagerWithPlugins(map[string]map[string]string{
"test-lyrics": {"format": format},
}, "test-lyrics"+PackageExtension)
p, ok := manager.LoadLyricsProvider("test-lyrics")
Expect(ok).To(BeTrue())
track := &model.MediaFile{ID: "track-1", Title: "Test Song", Artist: "Test Artist"}
result, err := p.GetLyrics(GinkgoT().Context(), track)
Expect(err).ToNot(HaveOccurred())
Expect(result).To(HaveLen(1))
Expect(result[0].Synced).To(Equal(wantSynced), "unexpected Synced value for format %s", format)
Expect(result[0].Line).To(HaveLen(1))
Expect(result[0].Line[0].Value).To(Equal(wantLine))
},
Entry("ttml", "ttml", true, "plugin ttml line"),
Entry("srt", "srt", true, "plugin srt line"),
Entry("yaml", "yaml", true, "plugin yaml line"),
Entry("lrc", "lrc", true, "plugin lrc line"),
Entry("plain", "plain", false, "plugin plain line"),
)
})
Describe("PluginNames", func() {
It("returns plugin names with Lyrics capability", func() {
names := lyricsManager.PluginNames("Lyrics")
Expect(names).To(ContainElement("test-lyrics"))
})
It("does not return metadata agent plugins for Lyrics capability", func() {
names := lyricsManager.PluginNames("Lyrics")
Expect(names).ToNot(ContainElement("test-metadata-agent"))
})
})
})