fix(distributed): stage backend companion assets to remote nodes (#10330)

A model whose ModelFile is a single file (e.g. sherpa-onnx VITS/piper: the
.onnx) failed to load on remote worker nodes because the sibling assets the
backend resolves from the model dir — tokens.txt, lexicon.txt, the
espeak-ng-data / dict directories, Kokoro's voices.bin — were never staged.
Only the declared ModelFile was shipped, so the worker hit "failed to create
sherpa-onnx TTS engine" and TTS produced no audio.

Lean on the existing option-path staging instead of hardcoding filenames:

- stageGenericOptions now also resolves an option value relative to the model's
  own directory (not just the frontend models dir), so a shared config can
  declare companions with bare names regardless of whether Model includes a
  subdirectory; and it expands directory-valued options (e.g. espeak-ng-data)
  file-by-file rather than handing a directory fd to the stager.
- gallery/sherpa-onnx-tts.yaml declares the companion assets as option paths
  (tokens, lexicon, espeak-ng-data, voices.bin, dict, per-lang lexicons). The
  backend ignores these keys and keeps resolving siblings from the model dir;
  they exist only so distributed staging ships them. Absent files are skipped.

Adds router_optionstage_test.go covering file + directory companion staging via
the model-dir fallback.

Co-authored-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

core/services/nodes/router.go

@@ -908,6 +908,17 @@ func (r *SmartRouter) stageModelFiles(ctx context.Context, node *BackendNode, op
 		frontendModelsDir = filepath.Clean(strings.TrimSuffix(opts.ModelFile, opts.Model))
 	}
 
+	// Local model directory, captured before the ModelFile field is rewritten to
+	// its remote path below. Companion assets declared as option paths (e.g.
+	// sherpa-onnx's tokens.txt / espeak-ng-data) live beside the model, so option
+	// values are resolved relative to this dir as well as frontendModelsDir —
+	// letting a shared config declare them with bare names regardless of whether
+	// Model includes a subdirectory.
+	localModelDir := ""
+	if opts.ModelFile != "" {
+		localModelDir = filepath.Dir(opts.ModelFile)
+	}
+
 	// keyMapper generates storage keys namespaced under trackingKey, preserving
 	// subdirectory structure relative to frontendModelsDir. This ensures:
 	// 1. All files for a model land in one directory on the worker for clean deletion
@@ -1079,8 +1090,8 @@ func (r *SmartRouter) stageModelFiles(ctx context.Context, node *BackendNode, op
 
 	// Stage file paths referenced in generic Options (key:value pairs where values
 	// are file paths). Options stay as relative paths — backends resolve them via ModelPath.
-	r.stageGenericOptions(ctx, node, opts.Options, frontendModelsDir, keyMapper.Key)
-	r.stageGenericOptions(ctx, node, opts.Overrides, frontendModelsDir, keyMapper.Key)
+	r.stageGenericOptions(ctx, node, opts.Options, frontendModelsDir, localModelDir, keyMapper.Key)
+	r.stageGenericOptions(ctx, node, opts.Overrides, frontendModelsDir, localModelDir, keyMapper.Key)
 
 	return opts, nil
 }
@@ -1196,36 +1207,86 @@ func (r *SmartRouter) stageCompanionFiles(ctx context.Context, node *BackendNode
 }
 
 // stageGenericOptions iterates key:value option strings and stages any values
-// that resolve to existing files relative to the frontend models directory.
-// Option values are NOT rewritten — backends resolve them via ModelPath.
-// keyFn generates the namespaced storage key for each file path.
-func (r *SmartRouter) stageGenericOptions(ctx context.Context, node *BackendNode, options []string, frontendModelsDir string, keyFn func(string) string) {
+// that resolve to existing files relative to the frontend models directory or
+// the model's own directory. Option values are NOT rewritten — backends resolve
+// them via ModelPath. keyFn generates the namespaced storage key for each file.
+func (r *SmartRouter) stageGenericOptions(ctx context.Context, node *BackendNode, options []string, frontendModelsDir, modelDir string, keyFn func(string) string) {
 	for _, opt := range options {
 		optKey, val, ok := strings.Cut(opt, ":")
 		if !ok || val == "" {
 			continue
 		}
 
-		// Check if value is an existing file path (absolute or relative to frontend models dir)
-		absPath := val
-		if !filepath.IsAbs(val) && frontendModelsDir != "" {
-			absPath = filepath.Join(frontendModelsDir, val)
+		// Resolve the value to an existing path: absolute as-is, otherwise
+		// relative to frontendModelsDir first, then the model's own directory
+		// (where backends like sherpa-onnx keep companion assets such as
+		// tokens.txt and espeak-ng-data).
+		absPath, ok := resolveOptionPath(val, frontendModelsDir, modelDir)
+		if !ok {
+			continue
 		}
-		if _, err := os.Stat(absPath); os.IsNotExist(err) {
+		info, err := os.Stat(absPath)
+		if err != nil {
+			continue
+		}
+
+		// A directory option value (e.g. sherpa-onnx's espeak-ng-data) is staged
+		// file-by-file so the whole tree is recreated beside the model on the
+		// worker; a single file is staged directly. Values are never rewritten —
+		// backends resolve relative paths via ModelPath.
+		if err == nil && info.IsDir() {
+			r.stageOptionDir(ctx, node, absPath, keyFn)
+			xlog.Debug("Staged option directory", "option", optKey, "localPath", absPath)
 			continue
 		}
 
-		// Stage the file to the worker using the namespaced key
 		key := keyFn(absPath)
 		if _, err := r.fileStager.EnsureRemote(ctx, node.ID, absPath, key); err != nil {
 			xlog.Warn("Failed to stage option file, skipping", "option", opt, "path", absPath, "error", err)
 			continue
 		}
-		// Leave option value unchanged — backend resolves relative paths via ModelPath
 		xlog.Debug("Staged option file", "option", optKey, "localPath", absPath)
 	}
 }
 
+// resolveOptionPath finds an existing local path for an option value: an
+// absolute path as-is, otherwise relative to frontendModelsDir, then to the
+// model's own directory. Returns false when none exists.
+func resolveOptionPath(val, frontendModelsDir, modelDir string) (string, bool) {
+	if filepath.IsAbs(val) {
+		if _, err := os.Stat(val); err == nil {
+			return val, true
+		}
+		return "", false
+	}
+	for _, base := range []string{frontendModelsDir, modelDir} {
+		if base == "" {
+			continue
+		}
+		p := filepath.Join(base, val)
+		if _, err := os.Stat(p); err == nil {
+			return p, true
+		}
+	}
+	return "", false
+}
+
+// stageOptionDir stages every regular file under an option-declared directory
+// (e.g. sherpa-onnx's espeak-ng-data) using the structure-preserving key, so the
+// tree is recreated beside the model on the worker. Per-file errors are logged
+// and skipped; the option value itself is not rewritten.
+func (r *SmartRouter) stageOptionDir(ctx context.Context, node *BackendNode, dir string, keyFn func(string) string) {
+	_ = filepath.WalkDir(dir, func(path string, d fs.DirEntry, walkErr error) error {
+		if walkErr != nil || d.IsDir() {
+			return nil
+		}
+		if _, err := r.fileStager.EnsureRemote(ctx, node.ID, path, keyFn(path)); err != nil {
+			xlog.Warn("Failed to stage option directory file, skipping", "path", path, "error", err)
+		}
+		return nil
+	})
+}
+
 // probeHealth checks whether a backend process on the given node/addr is alive
 // via a gRPC health check with a 2-second timeout. The client is closed after
 // the check.

core/services/nodes/router_optionstage_test.go

@@ -0,0 +1,77 @@
+package nodes
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	pb "github.com/mudler/LocalAI/pkg/grpc/proto"
+)
+
+// These tests cover staging of companion assets declared as option file paths
+// (the "vae_path:..." convention). Backends like sherpa-onnx keep a single-file
+// ModelFile (the .onnx) but resolve sibling assets — tokens.txt and the
+// espeak-ng-data directory — relative to the model dir. Those siblings must be
+// shipped to remote workers too, including directory-valued options expanded
+// file-by-file.
+var _ = Describe("stageGenericOptions companion assets", func() {
+	var (
+		stager *fakeFileStager
+		router *SmartRouter
+		node   *BackendNode
+		tmp    string
+	)
+
+	BeforeEach(func() {
+		stager = &fakeFileStager{}
+		router = &SmartRouter{
+			fileStager:     stager,
+			stagingTracker: NewStagingTracker(),
+		}
+		node = &BackendNode{ID: "node-1", Name: "node-1", Address: "10.0.0.1:50051"}
+		tmp = GinkgoT().TempDir()
+	})
+
+	It("stages option-declared sibling files and expands directory options", func() {
+		modelRel := "vits-piper-it_IT-paola-medium"
+		modelDir := filepath.Join(tmp, "models", modelRel)
+		dataDir := filepath.Join(modelDir, "espeak-ng-data")
+		Expect(os.MkdirAll(filepath.Join(dataDir, "lang"), 0o755)).To(Succeed())
+
+		onnx := filepath.Join(modelDir, "it_IT-paola-medium.onnx")
+		tokens := filepath.Join(modelDir, "tokens.txt")
+		phontab := filepath.Join(dataDir, "phontab")
+		langIt := filepath.Join(dataDir, "lang", "it")
+		for _, f := range []string{onnx, tokens, phontab, langIt} {
+			Expect(os.WriteFile(f, []byte("x"), 0o644)).To(Succeed())
+		}
+
+		opts := &pb.ModelOptions{
+			Model:     filepath.Join(modelRel, "it_IT-paola-medium.onnx"),
+			ModelFile: onnx,
+			// Bare names: not found under the models root (Model includes a
+			// subdir), so they must resolve relative to the model's own dir.
+			Options: []string{
+				"tts.noise_scale=0.667", // not a path; ignored by staging
+				"tokens:tokens.txt",
+				"data_dir:espeak-ng-data",
+			},
+		}
+
+		_, err := router.stageModelFiles(context.Background(), node, opts, "track-key")
+		Expect(err).ToNot(HaveOccurred())
+
+		staged := make([]string, 0, len(stager.ensureCalls))
+		for _, c := range stager.ensureCalls {
+			staged = append(staged, c.localPath)
+		}
+		// The .onnx (ModelFile), the tokens.txt file option, and every file under
+		// the espeak-ng-data directory option are staged; the directory path
+		// itself is never handed to the stager.
+		Expect(staged).To(ContainElements(onnx, tokens, phontab, langIt))
+		Expect(staged).ToNot(ContainElement(dataDir))
+	})
+})

gallery/sherpa-onnx-tts.yaml

@@ -12,3 +12,17 @@ config_file: |
     # Speech rate multiplier. Applied at every TTS / TTSStream call
     # since the TTSRequest proto has no speed field.
     - tts.speed=1.0
+    # Companion assets that sherpa-onnx TTS voices load from beside the .onnx
+    # (tokens, lexicons, espeak-ng phonemization data, Kokoro voices bank / jieba
+    # dict). Declared as option paths so distributed inference stages them to
+    # remote worker nodes too; the backend ignores these keys and resolves the
+    # files relative to the model dir. Bare names resolve against the model's own
+    # directory; any that a given voice doesn't ship are skipped during staging.
+    - tokens:tokens.txt
+    - lexicon:lexicon.txt
+    - data_dir:espeak-ng-data
+    - voices:voices.bin
+    - dict_dir:dict
+    - lexicon_us:lexicon-us-en.txt
+    - lexicon_gb:lexicon-gb-en.txt
+    - lexicon_zh:lexicon-zh.txt