adds tracing for all bus calls that passes ctx (#29434)

Signed-off-by: bergquist <carl.bergquist@gmail.com>

pkg/api/alerting.go

@@ -433,7 +433,7 @@ func NotificationTest(c *models.ReqContext, dto dtos.NotificationTestCommand) Re
 		SecureSettings: dto.SecureSettings,
 	}
 
-	if err := bus.Dispatch(cmd); err != nil {
+	if err := bus.DispatchCtx(c.Req.Context(), cmd); err != nil {
 		if errors.Is(err, models.ErrSmtpNotEnabled) {
 			return Error(412, err.Error(), err)
 		}

pkg/bus/bus.go

@@ -5,6 +5,8 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
+
+	"github.com/opentracing/opentracing-go"
 )
 
 // HandlerFunc defines a handler function interface.
@@ -84,6 +86,11 @@ func (b *InProcBus) SetTransactionManager(tm TransactionManager) {
 func (b *InProcBus) DispatchCtx(ctx context.Context, msg Msg) error {
 	var msgName = reflect.TypeOf(msg).Elem().Name()
 
+	span, ctx := opentracing.StartSpanFromContext(ctx, "bus - "+msgName)
+	defer span.Finish()
+
+	span.SetTag("msg", msgName)
+
 	var handler = b.handlersWithCtx[msgName]
 	if handler == nil {
 		return ErrHandlerNotFound

pkg/services/alerting/test_notification.go

@@ -30,10 +30,10 @@ var (
 )
 
 func init() {
-	bus.AddHandler("alerting", handleNotificationTestCommand)
+	bus.AddHandlerCtx("alerting", handleNotificationTestCommand)
 }
 
-func handleNotificationTestCommand(cmd *NotificationTestCommand) error {
+func handleNotificationTestCommand(ctx context.Context, cmd *NotificationTestCommand) error {
 	notifier := newNotificationService(nil)
 
 	model := &models.AlertNotification{