Dashboards: set max length of message to 500 (#99229)

pkg/services/dashboards/errors.go

@@ -70,6 +70,10 @@ var (
 		Reason:     "uid too long, max 40 characters",
 		StatusCode: 400,
 	}
+	ErrDashboardMessageTooLong = DashboardErr{
+		Reason:     "message too long, max 500 characters",
+		StatusCode: 400,
+	}
 	ErrDashboardCannotSaveProvisionedDashboard = DashboardErr{
 		Reason:     "Cannot save provisioned dashboard",
 		StatusCode: 400,

pkg/services/dashboards/service/dashboard_service.go

@@ -353,6 +353,10 @@ func (dr *DashboardServiceImpl) BuildSaveDashboardCommand(ctx context.Context, d
 		return nil, dashboards.ErrDashboardTitleEmpty
 	}
 
+	if len(dto.Message) > 500 {
+		return nil, dashboards.ErrDashboardMessageTooLong
+	}
+
 	metrics.MFolderIDsServiceCount.WithLabelValues(metrics.Dashboard).Inc()
 	// nolint:staticcheck
 	if dash.IsFolder && dash.FolderID > 0 {

pkg/services/dashboards/service/dashboard_service_test.go

@@ -67,6 +67,22 @@ func TestDashboardService(t *testing.T) {
 				}
 			})
 
+			t.Run("Should return validation error if message is too long", func(t *testing.T) {
+				dto.Dashboard = dashboards.NewDashboard("Dash")
+				dto.Message = `Here we go, 500+ characters for testing. I'm sorry that you're
+				having to read this. I spent too long trying to come up with something clever 
+				to say or a funny joke. Unforuntately, nothing came to mind. So instead, I'm
+				will share this with you, as a form of payment for having to read this:
+				https://youtu.be/dQw4w9WgXcQ?si=KeoTIpn9tUtQnOBk! Enjoy :) Now lets see if 
+				this test passes or if the result is more exciting than these 500 characters
+				I wrote. Best of luck to the both of us!`
+				_, err := service.SaveDashboard(context.Background(), dto, false)
+				require.Equal(t, err, dashboards.ErrDashboardMessageTooLong)
+
+				// set to a shorter message for the rest of the tests
+				dto.Message = `message`
+			})
+
 			t.Run("Should return validation error if folder is named General", func(t *testing.T) {
 				dto.Dashboard = dashboards.NewDashboardFolder("General")
 				_, err := service.SaveDashboard(context.Background(), dto, false)