in robot_ws/src/navigation_robot/nodes/monitor_distance_to_goal.py [0:0]
def __init__(self):
self.scan_sub = rospy.Subscriber(
'/move_base/NavfnROS/plan', Path, callback=self.report_metric
)
self.metric_pub = rospy.Publisher('/distance_to_goal', Float32, queue_size=1)