fibonacci_server.py

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#! /usr/bin/env python

# Copyright (c) 2010, Washington University in St. Louis
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import roslib; roslib.load_manifest('actionlib_tutorials')
import rospy

import actionlib

import actionlib_tutorials.msg

class FibonacciAction(object):
        # create messages that are used to publish feedback/result
        _feedback = actionlib_tutorials.msg.FibonacciFeedback()
        _result   = actionlib_tutorials.msg.FibonacciResult()

        def __init__(self, name):
                self._action_name = name
                _as = actionlib.SimpleActionServer(self._action_name, actionlib_tutorials.msg.FibonacciAction, execute_cb=self.execute_cb, auto_start=False)
                _as.start()
                self._as = _as
                
        def execute_cb(self, goal):
                # helper variables
                r = rospy.Rate(1)
                success = True
                
                # append the seeds for the fibonacci sequence
                self._feedback.sequence = []
                self._feedback.sequence.append(0)
                self._feedback.sequence.append(1)
                
                # publish info to the console for the user
                rospy.loginfo('%s: Executing, creating fibonacci sequence of order %i with seeds %i, %i' % (self._action_name, goal.order, self._feedback.sequence[0], self._feedback.sequence[1]))
                
                # start executing the action
                for i in xrange(1, goal.order):
                        # check that preempt has not been requested by the client
                        if self._as.is_preempt_requested():
                                rospy.loginfo('%s: Preempted' % self._action_name)
                                self._as.set_preempted()
                                success = False
                                break
                        self._feedback.sequence.append(self._feedback.sequence[i] + self._feedback.sequence[i-1])
                        # publish the feedback
                        self._as.publish_feedback(self._feedback)
                        # this step is not necessary, the sequence is computed at 1 Hz for demonstration purposes
                        r.sleep()
                        
                if success:
                        self._result.sequence = self._feedback.sequence
                        rospy.loginfo('%s: Succeeded' % self._action_name)
                        self._as.set_succeeded(self._result)
                        
if __name__ == '__main__':
  rospy.init_node('fibonacci')
  FibonacciAction(rospy.get_name())
  rospy.spin()