Source Code for Module smach_ros.util

 1   
 2  import roslib; roslib.load_manifest('smach_ros') 
 3  import rospy 
 4   
 5  import threading 
 6  import smach 
 7   
 8  __all__ = ['set_preempt_handler'] 
 9   
10  # Signal handler 
11 -def set_preempt_handler(sc): 
12      """Sets a ROS pre-shutdown handler to preempt a given SMACH container when 
13      ROS receives a shutdown request. 
14       
15      This can be attached to multiple containers, but only needs to be used on 
16      the top-level containers. 
17   
18      @type sc: L{smach.Container} 
19      @param sc: Container to preempt on ROS shutdown. 
20      """ 
21      ### Define handler 
22      def handler(sc): 
23          sc.request_preempt() 
24   
25          while sc.is_running(): 
26              rospy.loginfo("Received shutdown request... sent preempt... waiting for state machine to terminate.") 
27              rospy.sleep(1.0) 
28   
29      ### Add handler 
30      rospy.core.add_client_shutdown_hook(lambda: handler(sc)) 
31