[JTC] Fill action error_strings (#887)

Author: christophfroehlich

joint_trajectory_controller/src/joint_trajectory_controller.cpp

@@ -294,6 +294,7 @@ controller_interface::return_type JointTrajectoryController::update(
         {
           auto result = std::make_shared<FollowJTrajAction::Result>();
           result->set__error_code(FollowJTrajAction::Result::PATH_TOLERANCE_VIOLATED);
+          result->set__error_string("Aborted due to path tolerance violation");
           active_goal->setAborted(result);
           // TODO(matthew-reynolds): Need a lock-free write here
           // See https://github.com/ros-controls/ros2_controllers/issues/168
@@ -310,9 +311,10 @@ controller_interface::return_type JointTrajectoryController::update(
         {
           if (!outside_goal_tolerance)
           {
-            auto res = std::make_shared<FollowJTrajAction::Result>();
-            res->set__error_code(FollowJTrajAction::Result::SUCCESSFUL);
-            active_goal->setSucceeded(res);
+            auto result = std::make_shared<FollowJTrajAction::Result>();
+            result->set__error_code(FollowJTrajAction::Result::SUCCESSFUL);
+            result->set__error_string("Goal successfully reached!");
+            active_goal->setSucceeded(result);
             // TODO(matthew-reynolds): Need a lock-free write here
             // See https://github.com/ros-controls/ros2_controllers/issues/168
             rt_active_goal_.writeFromNonRT(RealtimeGoalHandlePtr());
@@ -325,17 +327,19 @@ controller_interface::return_type JointTrajectoryController::update(
           }
           else if (!within_goal_time)
           {
+            const std::string error_string = "Aborted due to goal_time_tolerance exceeding by " +
+                                             std::to_string(time_difference) + " seconds";
+
             auto result = std::make_shared<FollowJTrajAction::Result>();
             result->set__error_code(FollowJTrajAction::Result::GOAL_TOLERANCE_VIOLATED);
+            result->set__error_string(error_string);
             active_goal->setAborted(result);
             // TODO(matthew-reynolds): Need a lock-free write here
             // See https://github.com/ros-controls/ros2_controllers/issues/168
             rt_active_goal_.writeFromNonRT(RealtimeGoalHandlePtr());
             rt_has_pending_goal_.writeFromNonRT(false);
 
-            RCLCPP_WARN(
-              get_node()->get_logger(), "Aborted due goal_time_tolerance exceeding by %f seconds",
-              time_difference);
+            RCLCPP_WARN(get_node()->get_logger(), error_string.c_str());
 
             traj_msg_external_point_ptr_.reset();
             traj_msg_external_point_ptr_.initRT(set_hold_position());