FrontendService: Add tracing to frontend service (#107236)

* FrontendService: Add tracing to frontend service

* wire gen

* fix test

pkg/server/module_server.go

@@ -19,6 +19,7 @@ import (
 
 	"github.com/grafana/grafana/pkg/api"
 	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/infra/tracing"
 	"github.com/grafana/grafana/pkg/modules"
 	"github.com/grafana/grafana/pkg/services/authz"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
@@ -39,6 +40,7 @@ func NewModule(opts Options,
 	indexMetrics *resource.BleveIndexMetrics,
 	reg prometheus.Registerer,
 	promGatherer prometheus.Gatherer,
+	tracer tracing.Tracer, // Ensures tracing is initialized
 	license licensing.Licensing,
 ) (*ModuleServer, error) {
 	s, err := newModuleServer(opts, apiOpts, features, cfg, storageMetrics, indexMetrics, reg, promGatherer, license)

pkg/server/search_server_distributor_test.go

@@ -15,6 +15,7 @@ import (
 	claims "github.com/grafana/authlib/types"
 	"github.com/grafana/grafana/pkg/api"
 	"github.com/grafana/grafana/pkg/apimachinery/identity"
+	"github.com/grafana/grafana/pkg/infra/tracing"
 	"github.com/grafana/grafana/pkg/modules"
 	"github.com/grafana/grafana/pkg/services/featuremgmt"
 	"github.com/grafana/grafana/pkg/services/sqlstore/sqlutil"
@@ -321,7 +322,9 @@ func initModuleServerForTest(
 	opts Options,
 	apiOpts api.ServerOptions,
 ) testModuleServer {
-	ms, err := NewModule(opts, apiOpts, featuremgmt.WithFeatures(featuremgmt.FlagUnifiedStorageSearch), cfg, nil, nil, prometheus.NewRegistry(), prometheus.DefaultGatherer, nil)
+	tracer := tracing.InitializeTracerForTest()
+
+	ms, err := NewModule(opts, apiOpts, featuremgmt.WithFeatures(featuremgmt.FlagUnifiedStorageSearch), cfg, nil, nil, prometheus.NewRegistry(), prometheus.DefaultGatherer, tracer, nil)
 	require.NoError(t, err)
 
 	conn, err := grpc.NewClient(cfg.GRPCServer.Address,

pkg/server/wire_gen.go

@@ -1379,9 +1379,17 @@ func InitializeModuleServer(cfg *setting.Cfg, opts Options, apiOpts api.ServerOp
 	storageMetrics := resource.ProvideStorageMetrics(registerer)
 	bleveIndexMetrics := resource.ProvideIndexMetrics(registerer)
 	gatherer := metrics.ProvideGatherer()
+	tracingConfig, err := tracing.ProvideTracingConfig(cfg)
+	if err != nil {
+		return nil, err
+	}
+	tracingService, err := tracing.ProvideService(tracingConfig)
+	if err != nil {
+		return nil, err
+	}
 	hooksService := hooks.ProvideService()
 	ossLicensingService := licensing.ProvideService(cfg, hooksService)
-	moduleServer, err := NewModule(opts, apiOpts, featureToggles, cfg, storageMetrics, bleveIndexMetrics, registerer, gatherer, ossLicensingService)
+	moduleServer, err := NewModule(opts, apiOpts, featureToggles, cfg, storageMetrics, bleveIndexMetrics, registerer, gatherer, tracingService, ossLicensingService)
 	if err != nil {
 		return nil, err
 	}

pkg/server/wireexts_oss.go

@@ -8,6 +8,7 @@ import (
 	"github.com/google/wire"
 
 	"github.com/grafana/grafana/pkg/infra/metrics"
+	"github.com/grafana/grafana/pkg/infra/tracing"
 	"github.com/grafana/grafana/pkg/plugins"
 	"github.com/grafana/grafana/pkg/plugins/manager"
 	"github.com/grafana/grafana/pkg/registry"
@@ -165,6 +166,10 @@ var wireExtsBaseCLISet = wire.NewSet(
 var wireExtsModuleServerSet = wire.NewSet(
 	NewModule,
 	wireExtsBaseCLISet,
+	// Tracing
+	tracing.ProvideTracingConfig,
+	tracing.ProvideService,
+	wire.Bind(new(tracing.Tracer), new(*tracing.TracingService)),
 	// Unified storage
 	resource.ProvideStorageMetrics,
 	resource.ProvideIndexMetrics,

pkg/services/frontend/frontend_service.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"go.opentelemetry.io/otel"
 
 	"github.com/grafana/dskit/services"
 	"github.com/grafana/grafana/pkg/infra/log"
@@ -15,6 +16,8 @@ import (
 	"github.com/grafana/grafana/pkg/setting"
 )
 
+var tracer = otel.Tracer("github.com/grafana/grafana/pkg/services/frontend")
+
 type frontendService struct {
 	*services.BasicService
 	cfg          *setting.Cfg

pkg/services/frontend/index.go

@@ -79,6 +79,9 @@ func NewIndexProvider(cfg *setting.Cfg, license licensing.Licensing) (*IndexProv
 }
 
 func (p *IndexProvider) HandleRequest(writer http.ResponseWriter, request *http.Request) {
+	_, span := tracer.Start(request.Context(), "frontend.index.HandleRequest")
+	defer span.End()
+
 	if request.Method != "GET" {
 		writer.WriteHeader(http.StatusMethodNotAllowed)
 		return