scraper/internal/server/server.go

@@ -188,6 +188,10 @@ func (s *Server) ListenAndServe(ctx context.Context) error {
 
 	s.log.Info("HTTP server listening", "addr", s.addr)
 
+	// Pre-populate voice samples in the background so the UI voice selector
+	// has playable previews without requiring a manual trigger.
+	go s.warmVoiceSamples(ctx)
+
 	select {
 	case <-ctx.Done():
 		shutCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
@@ -1486,6 +1490,78 @@ func voiceSampleKey(voice string) string {
 	return fmt.Sprintf("_voice-samples/%s.mp3", safe)
 }
 
+// warmVoiceSamples runs at startup in a background goroutine.
+// It generates a short audio sample for every available Kokoro voice that
+// doesn't already have one in MinIO, so the UI voice selector has playable
+// previews without requiring a manual trigger.
+// It respects ctx cancellation and waits up to 30 s for Kokoro to become
+// reachable before giving up.
+func (s *Server) warmVoiceSamples(ctx context.Context) {
+	if s.kokoroURL == "" {
+		return
+	}
+
+	// Wait for Kokoro to be reachable (it may still be starting up).
+	deadline := time.Now().Add(30 * time.Second)
+	for time.Now().Before(deadline) {
+		req, _ := http.NewRequestWithContext(ctx, http.MethodGet, s.kokoroURL+"/v1/audio/voices", nil)
+		resp, err := http.DefaultClient.Do(req)
+		if err == nil {
+			resp.Body.Close()
+			if resp.StatusCode == http.StatusOK {
+				break
+			}
+		}
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(3 * time.Second):
+		}
+	}
+
+	voices := s.voices()
+	s.log.Info("warming voice samples", "voices", len(voices))
+
+	generated, skipped, failed := 0, 0, 0
+	for _, voice := range voices {
+		if ctx.Err() != nil {
+			return
+		}
+
+		key := voiceSampleKey(voice)
+		if s.store.AudioExists(ctx, key) {
+			skipped++
+			continue
+		}
+
+		filename, err := s.generateSpeech(ctx, voiceSampleText, voice, 1.0)
+		if err != nil {
+			s.log.Warn("voice sample warmup: generation failed", "voice", voice, "err", err)
+			failed++
+			continue
+		}
+
+		audioData, err := s.downloadFromKokoro(ctx, filename)
+		if err != nil {
+			s.log.Warn("voice sample warmup: download failed", "voice", voice, "err", err)
+			failed++
+			continue
+		}
+
+		if err := s.store.PutAudio(ctx, key, audioData); err != nil {
+			s.log.Warn("voice sample warmup: upload failed", "voice", voice, "key", key, "err", err)
+			failed++
+			continue
+		}
+
+		s.log.Debug("voice sample warmed", "voice", voice)
+		generated++
+	}
+
+	s.log.Info("voice sample warmup complete",
+		"generated", generated, "skipped", skipped, "failed", failed)
+}
+
 // handleGenerateVoiceSamples handles POST /api/audio/voice-samples.
 // It generates short audio samples for each available voice and stores them
 // in the audio MinIO bucket so the UI can play them during voice selection.