FrontendService: Add tracing to frontend service (#107236)

* FrontendService: Add tracing to frontend service

* wire gen

* fix test

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