feat: Add Get Token Metrics to GRPC server (#3687)

* Add Get Token Metrics to GRPC server

Signed-off-by: Siddharth More <siddimore@gmail.com>

* Expose LocalAI endpoint

Signed-off-by: Siddharth More <siddimore@gmail.com>

---------

Signed-off-by: Siddharth More <siddimore@gmail.com>

core/backend/token_metrics.go

@@ -0,0 +1,44 @@
+package backend
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/mudler/LocalAI/core/config"
+	"github.com/mudler/LocalAI/pkg/grpc/proto"
+	model "github.com/mudler/LocalAI/pkg/model"
+)
+
+func TokenMetrics(
+	backend,
+	modelFile string,
+	loader *model.ModelLoader,
+	appConfig *config.ApplicationConfig,
+	backendConfig config.BackendConfig) (*proto.MetricsResponse, error) {
+	bb := backend
+	if bb == "" {
+		return nil, fmt.Errorf("backend is required")
+	}
+
+	grpcOpts := GRPCModelOpts(backendConfig)
+
+	opts := modelOpts(config.BackendConfig{}, appConfig, []model.Option{
+		model.WithBackendString(bb),
+		model.WithModel(modelFile),
+		model.WithContext(appConfig.Context),
+		model.WithAssetDir(appConfig.AssetsDestination),
+		model.WithLoadGRPCLoadModelOpts(grpcOpts),
+	})
+	model, err := loader.BackendLoader(opts...)
+	if err != nil {
+		return nil, err
+	}
+
+	if model == nil {
+		return nil, fmt.Errorf("could not loadmodel model")
+	}
+
+	res, err := model.GetTokenMetrics(context.Background(), &proto.MetricsRequest{})
+
+	return res, err
+}