Example #1
0
class SimpleActionServer:
    ## @brief Constructor for a SimpleActionServer
    ## @param name A name for the action server
    ## @param execute_cb Optional callback that gets called in a separate thread whenever
    ## a new goal is received, allowing users to have blocking callbacks.
    ## Adding an execute callback also deactivates the goalCallback.
    ## @param  auto_start A boolean value that tells the ActionServer wheteher or not to start publishing as soon as it comes up. THIS SHOULD ALWAYS BE SET TO FALSE TO AVOID RACE CONDITIONS and start() should be called after construction of the server.
    def __init__(self, name, ActionSpec, execute_cb = None, auto_start = True):

        self.new_goal = False
        self.preempt_request = False
        self.new_goal_preempt_request = False

        self.execute_callback = execute_cb;
        self.goal_callback = None;
        self.preempt_callback = None;

        self.need_to_terminate = False
        self.terminate_mutex = threading.RLock();

        # since the internal_goal/preempt_callbacks are invoked from the
        # ActionServer while holding the self.action_server.lock
        # self.lock must always be locked after the action server lock
        # to avoid an inconsistent lock acquisition order
        self.lock = threading.RLock();

        self.execute_condition = threading.Condition(self.lock);

        self.current_goal = ServerGoalHandle();
        self.next_goal = ServerGoalHandle();

        if self.execute_callback:
            self.execute_thread = threading.Thread(None, self.executeLoop);
            self.execute_thread.start();
        else:
            self.execute_thread = None

        #create the action server
        self.action_server = ActionServer(name, ActionSpec, self.internal_goal_callback,self.internal_preempt_callback,auto_start);


    def __del__(self):
        if hasattr(self, 'execute_callback') and self.execute_callback:
            with self.terminate_mutex:
                self.need_to_terminate = True;

            assert(self.execute_thread);
            self.execute_thread.join();


    ## @brief Accepts a new goal when one is available The status of this
    ## goal is set to active upon acceptance, and the status of any
    ## previously active goal is set to preempted. Preempts received for the
    ## new goal between checking if isNewGoalAvailable or invokation of a
    ## goal callback and the acceptNewGoal call will not trigger a preempt
    ## callback.  This means, isPreemptReqauested should be called after
    ## accepting the goal even for callback-based implementations to make
    ## sure the new goal does not have a pending preempt request.
    ## @return A shared_ptr to the new goal.
    def accept_new_goal(self):
        with self.action_server.lock, self.lock:
            if not self.new_goal or not self.next_goal.get_goal():
                rospy.logerr("Attempting to accept the next goal when a new goal is not available");
                return None;

            #check if we need to send a preempted message for the goal that we're currently pursuing
            if self.is_active() and self.current_goal.get_goal() and self.current_goal != self.next_goal:
                self.current_goal.set_canceled(None, "This goal was canceled because another goal was received by the simple action server");

            rospy.logdebug("Accepting a new goal");

            #accept the next goal
            self.current_goal = self.next_goal;
            self.new_goal = False;

            #set preempt to request to equal the preempt state of the new goal
            self.preempt_request = self.new_goal_preempt_request;
            self.new_goal_preempt_request = False;

            #set the status of the current goal to be active
            self.current_goal.set_accepted("This goal has been accepted by the simple action server");

            return self.current_goal.get_goal();


    ## @brief Allows  polling implementations to query about the availability of a new goal
    ## @return True if a new goal is available, false otherwise
    def is_new_goal_available(self):
        return self.new_goal;


    ## @brief Allows  polling implementations to query about preempt requests
    ## @return True if a preempt is requested, false otherwise
    def is_preempt_requested(self):
        return self.preempt_request;

    ## @brief Allows  polling implementations to query about the status of the current goal
    ## @return True if a goal is active, false otherwise
    def is_active(self):
       if not self.current_goal.get_goal():
           return False;

       status = self.current_goal.get_goal_status().status;
       return status == actionlib_msgs.msg.GoalStatus.ACTIVE or status == actionlib_msgs.msg.GoalStatus.PREEMPTING;

    ## @brief Sets the status of the active goal to succeeded
    ## @param  result An optional result to send back to any clients of the goal
    def set_succeeded(self,result=None, text=""):
      with self.action_server.lock, self.lock:
          if not result:
              result=self.get_default_result();
          self.current_goal.set_succeeded(result, text);

    ## @brief Sets the status of the active goal to aborted
    ## @param  result An optional result to send back to any clients of the goal
    def set_aborted(self, result = None, text=""):
        with self.action_server.lock, self.lock:
            if not result:
                result=self.get_default_result();
            self.current_goal.set_aborted(result, text);

    ## @brief Publishes feedback for a given goal
    ## @param  feedback Shared pointer to the feedback to publish
    def publish_feedback(self,feedback):
        self.current_goal.publish_feedback(feedback);


    def get_default_result(self):
        return self.action_server.ActionResultType();

    ## @brief Sets the status of the active goal to preempted
    ## @param  result An optional result to send back to any clients of the goal
    def set_preempted(self,result=None, text=""):
        if not result:
            result=self.get_default_result();
        with self.action_server.lock, self.lock:
            rospy.logdebug("Setting the current goal as canceled");
            self.current_goal.set_canceled(result, text);

    ## @brief Allows users to register a callback to be invoked when a new goal is available
    ## @param cb The callback to be invoked
    def register_goal_callback(self,cb):
        if self.execute_callback:
            rospy.logwarn("Cannot call SimpleActionServer.register_goal_callback() because an executeCallback exists. Not going to register it.");
        else:
            self.goal_callback = cb;

    ## @brief Allows users to register a callback to be invoked when a new preempt request is available
    ## @param cb The callback to be invoked
    def register_preempt_callback(self, cb):
        self.preempt_callback = cb;


    ## @brief Explicitly start the action server, used it auto_start is set to false
    def start(self):
        self.action_server.start();


    ## @brief Callback for when the ActionServer receives a new goal and passes it on
    def internal_goal_callback(self, goal):
          self.execute_condition.acquire();

          try:
              rospy.logdebug("A new goal %shas been recieved by the single goal action server",goal.get_goal_id().id);

              #check that the timestamp is past that of the current goal and the next goal
              if((not self.current_goal.get_goal() or goal.get_goal_id().stamp >= self.current_goal.get_goal_id().stamp)
                 and (not self.next_goal.get_goal() or goal.get_goal_id().stamp >= self.next_goal.get_goal_id().stamp)):
                  #if next_goal has not been accepted already... its going to get bumped, but we need to let the client know we're preempting
                  if(self.next_goal.get_goal() and (not self.current_goal.get_goal() or self.next_goal != self.current_goal)):
                      self.next_goal.set_canceled(None, "This goal was canceled because another goal was received by the simple action server");

                  self.next_goal = goal;
                  self.new_goal = True;
                  self.new_goal_preempt_request = False;

                  #if the server is active, we'll want to call the preempt callback for the current goal
                  if(self.is_active()):
                      self.preempt_request = True;
                      #if the user has registered a preempt callback, we'll call it now
                      if(self.preempt_callback):
                          self.preempt_callback();

                  #if the user has defined a goal callback, we'll call it now
                  if self.goal_callback:
                      self.goal_callback();

                  #Trigger runLoop to call execute()
                  self.execute_condition.notify();
                  self.execute_condition.release();
              else:
                  #the goal requested has already been preempted by a different goal, so we're not going to execute it
                  goal.set_canceled(None, "This goal was canceled because another goal was received by the simple action server");
                  self.execute_condition.release();
          except Exception, e:
              rospy.logerr("SimpleActionServer.internal_goal_callback - exception %s",str(e))
              self.execute_condition.release();
Example #2
0
class DockActionServer(ActionServer):
    def __init__(self, name):
        ActionServer.__init__(self, name, DockAction, self.__goal_callback,
                              self.__cancel_callback, False)

        self.__docked = False

        self.__dock_speed = rospy.get_param('~dock/dock_speed', 0.05)
        self.__dock_distance = rospy.get_param('~dock/dock_distance', 1.0)
        self.__map_frame = rospy.get_param('~map_frame', 'map')
        self.__odom_frame = rospy.get_param('~odom_frame', 'odom')
        self.__base_frame = rospy.get_param('~base_frame', 'base_footprint')

        self.__dock_ready_pose = Pose()
        self.__dock_ready_pose.position.x = rospy.get_param('~dock/pose_x')
        self.__dock_ready_pose.position.y = rospy.get_param('~dock/pose_y')
        self.__dock_ready_pose.position.z = rospy.get_param('~dock/pose_z')
        self.__dock_ready_pose.orientation.x = rospy.get_param(
            '~dock/orientation_x')
        self.__dock_ready_pose.orientation.y = rospy.get_param(
            '~dock/orientation_y')
        self.__dock_ready_pose.orientation.z = rospy.get_param(
            '~dock/orientation_z')
        self.__dock_ready_pose.orientation.w = rospy.get_param(
            '~dock/orientation_w')

        self.__dock_ready_pose_2 = PoseStamped()

        rospy.loginfo('param: dock_spped, %s, dock_distance %s' %
                      (self.__dock_speed, self.__dock_distance))
        rospy.loginfo('param: map_frame %s, odom_frame %s, base_frame %s' %
                      (self.__map_frame, self.__odom_frame, self.__base_frame))
        rospy.loginfo('dock_pose:')
        rospy.loginfo(self.__dock_ready_pose)

        self.__movebase_client = SimpleActionClient('move_base',
                                                    MoveBaseAction)
        rospy.loginfo('wait for movebase server...')
        self.__movebase_client.wait_for_server()
        rospy.loginfo('movebase server connected')

        self.__cmd_pub = rospy.Publisher('cmd_vel', Twist, queue_size=10)

        rospy.Subscriber('dock_pose', PoseStamped, self.__dock_pose_callback)

        self.__tf_listener = tf.TransformListener()

        self.__docked = False
        # self.__saved_goal = MoveBaseGoal()

        self.__no_goal = True
        self.__current_goal_handle = ServerGoalHandle()
        self.__exec_condition = threading.Condition()
        self.__exec_thread = threading.Thread(None, self.__exec_loop)
        self.__exec_thread.start()

        rospy.loginfo('Creating ActionServer [%s]\n', name)

    def __del__(self):
        self.__movebase_client.cancel_all_goals()

    def __dock_pose_callback(self, data):
        ps = PoseStamped()
        # ps.header.stamp = rospy.Time.now()
        ps.header.frame_id = 'dock'
        ps.pose.position.x = -self.__dock_distance

        try:
            self.__dock_ready_pose_2 = self.__tf_listener.transformPose(
                'map', ps)
        except (tf.LookupException, tf.ConnectivityException,
                tf.ExtrapolationException) as e:
            self.__dock_ready_pose_2.pose.position.z = -1.0
            rospy.logwarn('tf error, %s' % e)

        self.__dock_ready_pose_2.pose.position.z = 0.0

        # rospy.loginfo('get dock pose')

    def __goal_callback(self, gh):
        rospy.loginfo('get new goal')
        if not self.__no_goal:
            gh.set_rejected(None, 'robot is busy, rejected')
            rospy.logwarn('robot is busy, rejected')
            return

        self.__exec_condition.acquire()

        self.__current_goal_handle = gh
        self.__no_goal = False
        self.__exec_condition.notify()

        self.__exec_condition.release()

    def __set_charge_relay(self, state):
        pass

    def __cancel_callback(self, gh):
        self.__movebase_client.cancel_goal()
        rospy.logwarn('cancel callback')

    def __get_delta(self, pose, target):
        if pose < 0:
            pose = math.pi * 2 + pose

        if target < 0:
            target = math.pi * 2 + target

        delta_a = target - pose
        delta_b = math.pi * 2 - math.fabs(delta_a)

        if delta_a > 0:
            delta_b = delta_b * -1.0

        if math.fabs(delta_a) < math.fabs(delta_b):
            return delta_a
        else:
            return delta_b

    def __rotate(self, delta):
        try:
            pose, quaternion = self.__tf_listener.lookupTransform(
                'odom', self.__base_frame, rospy.Time(0))
        except (tf.LookupException, tf.ConnectivityException,
                tf.ExtrapolationException) as e:
            rospy.logwarn(e)
            rospy.logwarn('tf error')

        (roll, pitch, yaw) = euler_from_quaternion(quaternion)
        target_yaw = yaw + delta
        if target_yaw > math.pi:
            target_yaw = target_yaw - (2.0 * math.pi)
        elif target_yaw < -math.pi:
            target_yaw = target_yaw + 2.0 * math.pi

        rospy.loginfo('rotate %f to %f', delta, target_yaw)

        cmd = Twist()
        time = rospy.Time.now() + rospy.Duration(15)
        while rospy.Time.now() < time and not rospy.is_shutdown(
        ) and math.fabs(self.__get_delta(yaw, target_yaw)) > 0.03:
            try:
                pose, quaternion = self.__tf_listener.lookupTransform(
                    'odom', self.__base_frame, rospy.Time(0))
            except (tf.LookupException, tf.ConnectivityException,
                    tf.ExtrapolationException) as e:
                rospy.logwarn(e)
                rospy.logwarn('tf error')

            (roll, pitch, yaw) = euler_from_quaternion(quaternion)

            a = self.__get_delta(yaw, target_yaw) * 0.4

            if a > 0 and a < 0.08:
                cmd.angular.z = 0.08
            elif a < 0 and a > -0.08:
                cmd.angular.z = -0.08
            else:
                cmd.angular.z = a

            self.__cmd_pub.publish(cmd)
            rospy.loginfo('rotate %f : %f, delta %f, speed %f, %f', target_yaw,
                          yaw, self.__get_delta(yaw,
                                                target_yaw), a, cmd.angular.z)

        return True

    def __head_align(self):
        cmd = Twist()

        time = rospy.Time.now() + rospy.Duration(10)
        while rospy.Time.now() < time:
            try:
                dock_pose, dock_quaternion = self.__tf_listener.lookupTransform(
                    self.__base_frame, 'dock', rospy.Time(0))
            except (tf.LookupException, tf.ConnectivityException,
                    tf.ExtrapolationException) as e:
                rospy.logwarn(e)
                rospy.logwarn('tf error')

            # when dock's x is close to zero, it means dock is just in the front of robot(base_footprint)
            if dock_pose[1] < -0.002:
                cmd.angular.z = -0.08
            elif dock_pose[1] > 0.002:
                cmd.angular.z = 0.08
            else:
                cmd.angular.z = 0.00
                self.__cmd_pub.publish(cmd)
                break

            rospy.loginfo('algin %f, speed %f', dock_pose[1], cmd.angular.z)
            self.__cmd_pub.publish(cmd)

        self.__cmd_pub.publish(cmd)
        rospy.Rate(0.5).sleep()

        return True

    def __moveto_dock(self):
        cmd = Twist()
        cmd.linear.x = -self.__dock_speed

        ca_feedback = DockFeedback()

        try:
            last_pose, last_quaternion = self.__tf_listener.lookupTransform(
                self.__odom_frame, self.__base_frame, rospy.Time(0))
        except (tf.LookupException, tf.ConnectivityException,
                tf.ExtrapolationException) as e:
            rospy.logwarn(e)
            rospy.logwarn('tf error')

        delta_distance = 0
        while delta_distance < self.__dock_distance - 0.235 and not rospy.is_shutdown(
        ):
            self.__cmd_pub.publish(cmd)

            try:
                current_pose, current_quaternion = self.__tf_listener.lookupTransform(
                    self.__odom_frame, self.__base_frame, rospy.Time(0))
                delta_distance = math.sqrt(
                    math.pow(current_pose[0] - last_pose[0], 2) +
                    math.pow(current_pose[1] - last_pose[1], 2) +
                    math.pow(current_pose[2] - last_pose[2], 2))

                ca_feedback.dock_feedback = 'Moving to Dock, %fm left' % (
                    self.__dock_distance - delta_distance)
                self.__current_goal_handle.publish_feedback(ca_feedback)

                rospy.loginfo('Moving to Dock, %fm left' %
                              (self.__dock_distance - delta_distance))
            except (tf.LookupException, tf.ConnectivityException,
                    tf.ExtrapolationException) as e:
                rospy.logwarn(e)
                rospy.logwarn('tf error aa')

            rospy.Rate(20).sleep()

        ca_feedback.dock_feedback = 'Stop on Dock'
        self.__current_goal_handle.publish_feedback(ca_feedback)
        rospy.loginfo('stop robot')

        # stop robot
        cmd.linear.x = 0
        self.__cmd_pub.publish(cmd)

        # set charge relay on
        self.__set_charge_relay(True)

        return True

    def __moveto_dock_ready(self):
        # step 1
        mb_goal = MoveBaseGoal()
        mb_goal.target_pose.header.stamp = rospy.Time.now()
        mb_goal.target_pose.header.frame_id = self.__map_frame
        mb_goal.target_pose.header.seq = 1
        mb_goal.target_pose.pose = self.__dock_ready_pose

        self.__movebase_client.send_goal(mb_goal)

        self.__movebase_client.wait_for_result()
        rospy.loginfo('arrived dock_ready_pose')

        rospy.Rate(2).sleep()

        mb_goal = MoveBaseGoal()
        mb_goal.target_pose.header.seq = 2
        mb_goal.target_pose.header.stamp = rospy.Time.now()
        mb_goal.target_pose.header.frame_id = self.__map_frame

        if self.__dock_ready_pose_2.pose.position.z == -1.0:
            rospy.logwarn('dock_ready_pose_2 failed')
            return False
        else:
            rospy.loginfo('get dock ready pose 2 ()()')
            t = self.__dock_ready_pose_2.pose

        # t.position.z == 0.0
        # t.position.x = -self.__dock_distance
        mb_goal.target_pose.pose = t

        rospy.loginfo('move to dock_ready_pose_2')
        self.__movebase_client.cancel_all_goals()
        self.__movebase_client.send_goal(mb_goal)

        rospy.loginfo(self.__movebase_client.wait_for_result())
        rospy.loginfo('arrived dock_ready_pose_2')

        return True

    def __dock(self):
        if self.__moveto_dock_ready():
            if self.__head_align():
                if self.__rotate(math.pi):
                    if self.__moveto_dock():
                        self.__docked = True
                        return True
                    else:
                        rospy.logwarn("unable to move to dock")
                else:
                    rospy.logwarn("unable to rotate 180")
            else:
                rospy.logwarn("unable to align head")
        else:
            rospy.logwarn("unable to move to dock ready")

        self.__docked = False
        return False

    def __undock(self):
        cmd = Twist()
        cmd.linear.x = self.__dock_speed

        ca_feedback = DockFeedback()

        try:
            last_pose, last_quaternion = self.__tf_listener.lookupTransform(
                self.__odom_frame, self.__base_frame, rospy.Time(0))
        except (tf.LookupException, tf.ConnectivityException,
                tf.ExtrapolationException) as e:
            rospy.logwarn(e)
            rospy.logwarn('tf error')

        delta_distance = 0
        while delta_distance < self.__dock_distance - 0.275 and not rospy.is_shutdown(
        ):
            self.__cmd_pub.publish(cmd)

            try:
                current_pose, current_quaternion = self.__tf_listener.lookupTransform(
                    self.__odom_frame, self.__base_frame, rospy.Time(0))
                delta_distance = math.sqrt(
                    math.pow(current_pose[0] - last_pose[0], 2) +
                    math.pow(current_pose[1] - last_pose[1], 2) +
                    math.pow(current_pose[2] - last_pose[2], 2))

                ca_feedback.dock_feedback = 'Undock, %fm left' % (
                    self.__dock_distance - delta_distance)
                self.__current_goal_handle.publish_feedback(ca_feedback)

                rospy.loginfo('Undock, %fm left' %
                              (self.__dock_distance - delta_distance))
            except (tf.LookupException, tf.ConnectivityException,
                    tf.ExtrapolationException) as e:
                rospy.logwarn(e)
                rospy.logwarn('tf error aa')

            rospy.Rate(20).sleep()

        ca_feedback.dock_feedback = 'Stop on DockReady'
        self.__current_goal_handle.publish_feedback(ca_feedback)
        rospy.loginfo('stop robot')

        # stop robot
        cmd.linear.x = 0.0
        self.__cmd_pub.publish(cmd)

        # set charge relay off
        self.__set_charge_relay(False)

        self.__docked = False
        self.__current_goal_handle.set_succeeded(None, 'Undocked')
        rospy.loginfo('UnDocked')

    def __exec_loop(self):
        rospy.loginfo('auto dock thread started')

        while not rospy.is_shutdown():
            with self.__exec_condition:
                self.__exec_condition.wait(3)

            if self.__no_goal:
                continue

            rospy.loginfo('processing new goal')

            goal = self.__current_goal_handle.get_goal()

            if goal.dock == True:
                if self.__docked == True:
                    rospy.logwarn('rejected, robot has already docked')
                    self.__current_goal_handle.set_rejected(
                        None, 'already docked')
                else:
                    rospy.loginfo('Docking')
                    self.__current_goal_handle.set_accepted('Docking')
                    self.__dock()

                    if self.__docked:
                        self.__current_goal_handle.set_succeeded(
                            None, 'Docked')
                        rospy.loginfo('Docked')
                    else:
                        self.__current_goal_handle.set_aborted(
                            None, 'Dock failed')
                        rospy.loginfo('Dock failed')
            elif goal.dock == False:
                if self.__docked == False:
                    rospy.logwarn('cancel_all_goals')
                    self.__movebase_client.cancel_all_goals()
                    rospy.logwarn('rejected, robot is not on charging')
                    self.__current_goal_handle.set_rejected(
                        None, 'robot is not on charging')
                else:
                    rospy.loginfo('Start undock')
                    self.__current_goal_handle.set_accepted('Start undock')
                    self.__undock()
            else:
                rospy.logwarn(
                    'unknown dock data type, should be true or false')

            # self.__current_goal_handle.set_succeeded(None, 'Docked')
            rospy.loginfo('new goal finish')

            self.__no_goal = True

        rospy.loginfo('auto dock thread stop')
Example #3
0
class SimpleActionServer:
    ## @brief Constructor for a SimpleActionServer
    ## @param name A name for the action server
    ## @param execute_cb Optional callback that gets called in a separate thread whenever
    ## a new goal is received, allowing users to have blocking callbacks.
    ## Adding an execute callback also deactivates the goalCallback.
    ## @param  auto_start A boolean value that tells the ActionServer wheteher or not to start publishing as soon as it comes up. THIS SHOULD ALWAYS BE SET TO FALSE TO AVOID RACE CONDITIONS and start() should be called after construction of the server.
    def __init__(self, name, ActionSpec, execute_cb=None, auto_start=True):

        self.new_goal = False
        self.preempt_request = False
        self.new_goal_preempt_request = False

        self.execute_callback = execute_cb
        self.goal_callback = None
        self.preempt_callback = None

        self.need_to_terminate = False
        self.terminate_mutex = threading.RLock()

        # since the internal_goal/preempt_callbacks are invoked from the
        # ActionServer while holding the self.action_server.lock
        # self.lock must always be locked after the action server lock
        # to avoid an inconsistent lock acquisition order
        self.lock = threading.RLock()

        self.execute_condition = threading.Condition(self.lock)

        self.current_goal = ServerGoalHandle()
        self.next_goal = ServerGoalHandle()

        if self.execute_callback:
            self.execute_thread = threading.Thread(None, self.executeLoop)
            self.execute_thread.start()
        else:
            self.execute_thread = None

        #create the action server
        self.action_server = ActionServer(name, ActionSpec,
                                          self.internal_goal_callback,
                                          self.internal_preempt_callback,
                                          auto_start)

    def __del__(self):
        if hasattr(self, 'execute_callback') and self.execute_callback:
            with self.terminate_mutex:
                self.need_to_terminate = True

            assert (self.execute_thread)
            self.execute_thread.join()

    ## @brief Accepts a new goal when one is available The status of this
    ## goal is set to active upon acceptance, and the status of any
    ## previously active goal is set to preempted. Preempts received for the
    ## new goal between checking if isNewGoalAvailable or invokation of a
    ## goal callback and the acceptNewGoal call will not trigger a preempt
    ## callback.  This means, isPreemptReqauested should be called after
    ## accepting the goal even for callback-based implementations to make
    ## sure the new goal does not have a pending preempt request.
    ## @return A shared_ptr to the new goal.
    def accept_new_goal(self):
        with self.action_server.lock, self.lock:
            if not self.new_goal or not self.next_goal.get_goal():
                rospy.logerr(
                    "Attempting to accept the next goal when a new goal is not available"
                )
                return None

            # check if we need to send a preempted message for the goal that we're currently pursuing
            if self.is_active() and self.current_goal.get_goal(
            ) and self.current_goal != self.next_goal:
                self.current_goal.set_canceled(
                    None,
                    "This goal was canceled because another goal was received by the simple action server"
                )

            rospy.logdebug("Accepting a new goal")

            # accept the next goal
            self.current_goal = self.next_goal
            self.new_goal = False

            # set preempt to request to equal the preempt state of the new goal
            self.preempt_request = self.new_goal_preempt_request
            self.new_goal_preempt_request = False

            # set the status of the current goal to be active
            self.current_goal.set_accepted(
                "This goal has been accepted by the simple action server")

            return self.current_goal.get_goal()

    ## @brief Allows  polling implementations to query about the availability of a new goal
    ## @return True if a new goal is available, false otherwise
    def is_new_goal_available(self):
        return self.new_goal

    ## @brief Allows  polling implementations to query about preempt requests
    ## @return True if a preempt is requested, false otherwise
    def is_preempt_requested(self):
        return self.preempt_request

    ## @brief Allows  polling implementations to query about the status of the current goal
    ## @return True if a goal is active, false otherwise
    def is_active(self):
        if not self.current_goal.get_goal():
            return False

        status = self.current_goal.get_goal_status().status
        return status == actionlib_msgs.msg.GoalStatus.ACTIVE or status == actionlib_msgs.msg.GoalStatus.PREEMPTING

    ## @brief Sets the status of the active goal to succeeded
    ## @param  result An optional result to send back to any clients of the goal
    def set_succeeded(self, result=None, text=""):
        with self.action_server.lock, self.lock:
            if not result:
                result = self.get_default_result()
            self.current_goal.set_succeeded(result, text)

    ## @brief Sets the status of the active goal to aborted
    ## @param  result An optional result to send back to any clients of the goal
    def set_aborted(self, result=None, text=""):
        with self.action_server.lock, self.lock:
            if not result:
                result = self.get_default_result()
            self.current_goal.set_aborted(result, text)

    ## @brief Publishes feedback for a given goal
    ## @param  feedback Shared pointer to the feedback to publish
    def publish_feedback(self, feedback):
        self.current_goal.publish_feedback(feedback)

    def get_default_result(self):
        return self.action_server.ActionResultType()

    ## @brief Sets the status of the active goal to preempted
    ## @param  result An optional result to send back to any clients of the goal
    def set_preempted(self, result=None, text=""):
        if not result:
            result = self.get_default_result()
        with self.action_server.lock, self.lock:
            rospy.logdebug("Setting the current goal as canceled")
            self.current_goal.set_canceled(result, text)

    ## @brief Allows users to register a callback to be invoked when a new goal is available
    ## @param cb The callback to be invoked
    def register_goal_callback(self, cb):
        if self.execute_callback:
            rospy.logwarn(
                "Cannot call SimpleActionServer.register_goal_callback() because an executeCallback exists. Not going to register it."
            )
        else:
            self.goal_callback = cb

    ## @brief Allows users to register a callback to be invoked when a new preempt request is available
    ## @param cb The callback to be invoked
    def register_preempt_callback(self, cb):
        self.preempt_callback = cb

    ## @brief Explicitly start the action server, used it auto_start is set to false
    def start(self):
        self.action_server.start()

    ## @brief Callback for when the ActionServer receives a new goal and passes it on
    def internal_goal_callback(self, goal):
        self.execute_condition.acquire()

        try:
            rospy.logdebug(
                "A new goal %shas been recieved by the single goal action server",
                goal.get_goal_id().id)

            # check that the timestamp is past that of the current goal and the next goal
            if ((not self.current_goal.get_goal() or goal.get_goal_id().stamp
                 >= self.current_goal.get_goal_id().stamp) and
                (not self.next_goal.get_goal() or goal.get_goal_id().stamp >=
                 self.next_goal.get_goal_id().stamp)):
                # if next_goal has not been accepted already... its going to get bumped, but we need to let the client know we're preempting
                if (self.next_goal.get_goal()
                        and (not self.current_goal.get_goal()
                             or self.next_goal != self.current_goal)):
                    self.next_goal.set_canceled(
                        None,
                        "This goal was canceled because another goal was received by the simple action server"
                    )

                self.next_goal = goal
                self.new_goal = True
                self.new_goal_preempt_request = False

                # if the server is active, we'll want to call the preempt callback for the current goal
                if (self.is_active()):
                    self.preempt_request = True
                    # if the user has registered a preempt callback, we'll call it now
                    if (self.preempt_callback):
                        self.preempt_callback()

                # if the user has defined a goal callback, we'll call it now
                if self.goal_callback:
                    self.goal_callback()

                # Trigger runLoop to call execute()
                self.execute_condition.notify()
                self.execute_condition.release()
            else:
                # the goal requested has already been preempted by a different goal, so we're not going to execute it
                goal.set_canceled(
                    None,
                    "This goal was canceled because another goal was received by the simple action server"
                )
                self.execute_condition.release()
        except Exception as e:
            rospy.logerr(
                "SimpleActionServer.internal_goal_callback - exception %s",
                str(e))
            self.execute_condition.release()

    ## @brief Callback for when the ActionServer receives a new preempt and passes it on
    def internal_preempt_callback(self, preempt):
        with self.lock:
            rospy.logdebug(
                "A preempt has been received by the SimpleActionServer")

            #if the preempt is for the current goal, then we'll set the preemptRequest flag and call the user's preempt callback
            if (preempt == self.current_goal):
                rospy.logdebug(
                    "Setting preempt_request bit for the current goal to TRUE and invoking callback"
                )
                self.preempt_request = True

                #if the user has registered a preempt callback, we'll call it now
                if (self.preempt_callback):
                    self.preempt_callback()
            #if the preempt applies to the next goal, we'll set the preempt bit for that
            elif (preempt == self.next_goal):
                rospy.logdebug(
                    "Setting preempt request bit for the next goal to TRUE")
                self.new_goal_preempt_request = True

    ## @brief Called from a separate thread to call blocking execute calls
    def executeLoop(self):
        loop_duration = rospy.Duration.from_sec(.1)

        while (not rospy.is_shutdown()):
            with self.terminate_mutex:
                if (self.need_to_terminate):
                    break

            # the following checks (is_active, is_new_goal_available)
            # are performed without locking
            # the worst thing that might happen in case of a race
            # condition is a warning/error message on the console
            if (self.is_active()):
                rospy.logerr(
                    "Should never reach this code with an active goal")
                return

            if (self.is_new_goal_available()):
                # accept_new_goal() is performing its own locking
                goal = self.accept_new_goal()
                if not self.execute_callback:
                    rospy.logerr(
                        "execute_callback_ must exist. This is a bug in SimpleActionServer"
                    )
                    return

                try:
                    self.execute_callback(goal)

                    if self.is_active():
                        rospy.logwarn(
                            "Your executeCallback did not set the goal to a terminal status.  "
                            +
                            "This is a bug in your ActionServer implementation. Fix your code!  "
                            +
                            "For now, the ActionServer will set this goal to aborted"
                        )
                        self.set_aborted(None, "No terminal state was set.")
                except Exception as ex:
                    rospy.logerr("Exception in your execute callback: %s\n%s",
                                 str(ex), traceback.format_exc())
                    self.set_aborted(
                        None, "Exception in execute callback: %s" % str(ex))

            with self.execute_condition:
                self.execute_condition.wait(loop_duration.to_sec())
class QueuedActionServer:
    ## @brief Constructor for a QueuedActionServer
    ## @param name A name for the action server
    ## @param execute_cb Optional callback that gets called in a separate thread whenever
    ## a new goal is received, allowing users to have blocking callbacks.
    ## Adding an execute callback also deactivates the goalCallback.
    ## @param  auto_start A boolean value that tells the ActionServer wheteher or not to start publishing as soon as it comes up. THIS SHOULD ALWAYS BE SET TO FALSE TO AVOID RACE CONDITIONS and start() should be called after construction of the server.

	def __init__(self, name, ActionSpec, execute_cb = None, auto_start = True):

		self.new_goal = False
		self.preempt_request = False
		self.new_goal_preempt_request = False
		self.maxlen = 5

		#self.goals_buf = deque(maxlen=5)
		self.goals_buf = Queue.Queue(maxsize=self.maxlen)
		self.current_indexA = 0
		self.current_indexP = 0

		#self.maxlen = self.goals_buf.maxlen

		self.execute_callback = execute_cb
		self.goal_callback = None
		self.preempt_callback = None

		self.need_to_terminate = False
		self.terminate_mutex = threading.RLock()
		self.lock = threading.RLock()

		self.execute_condition = threading.Condition(self.lock)

		self.current_goal = ServerGoalHandle()
		self.next_goal = ServerGoalHandle()

		if self.execute_callback:
			self.execute_thread = threading.Thread(None, self.executeLoop)
			self.execute_thread.start()
		else:
			self.execute_thread = None

		#create the action server
		self.action_server = ActionServer(name, ActionSpec, self.internal_goal_callback,self.internal_preempt_callback,auto_start)


	def __del__(self):
		if hasattr(self, 'execute_callback') and self.execute_callback:
			with self.terminate_mutex:
				self.need_to_terminate = True

			assert(self.execute_thread)
			self.execute_thread.join()


    ## @brief Accepts a new goal when one is available The status of this
    ## goal is set to active upon acceptance, and the status of any
    ## previously active goal is set to preempted. Preempts received for the
    ## new goal between checking if isNewGoalAvailable or invokation of a
    ## goal callback and the acceptNewGoal call will not trigger a preempt
    ## callback.  This means, isPreemptReqauested should be called after
    ## accepting the goal even for callback-based implementations to make
    ## sure the new goal does not have a pending preempt request.
    ## @return A shared_ptr to the new goal.
	def accept_new_goal(self):

		
		with self.lock:
			if not self.new_goal or not self.next_goal.get_goal():
				rospy.logerr("Attempting to accept the next goal when a new goal is not available")
				return None

			rospy.logdebug("Accepting a new goal")

			#accept the next goal
			self.current_goal = self.next_goal
			self.new_goal = False

			#set preempt to request to equal the preempt state of the new goal
			self.preempt_request = self.new_goal_preempt_request
			self.new_goal_preempt_request = False

			#set the status of the current goal to be active
			self.current_goal.set_accepted("This goal has been accepted by the queued action server")

			return self.current_goal.get_goal()


    ## @brief Allows  polling implementations to query about the availability of a new goal
    ## @return True if a new goal is available, false otherwise
	def is_new_goal_available(self):
		return self.new_goal


    ## @brief Allows  polling implementations to query about preempt requests
    ## @return True if a preempt is requested, false otherwise
	def is_preempt_requested(self):
		return self.preempt_request

    ## @brief Allows  polling implementations to query about the status of the current goal
    ## @return True if a goal is active, false otherwise
	def is_active(self):
		if not self.current_goal.get_goal():
			return False

		status = self.current_goal.get_goal_status().status
		return status == actionlib_msgs.msg.GoalStatus.ACTIVE or status == actionlib_msgs.msg.GoalStatus.PREEMPTING

    ## @brief Sets the status of the active goal to succeeded
    ## @param  result An optional result to send back to any clients of the goal
	def set_succeeded(self,result=None, text=""):
		with self.lock:
			if not result:
				result=self.get_default_result()
			self.current_goal.set_succeeded(result, text)

    ## @brief Sets the status of the active goal to aborted
    ## @param  result An optional result to send back to any clients of the goal
	def set_aborted(self, result = None, text=""):
		with self.lock:
			if not result:
				result=self.get_default_result()
			self.current_goal.set_aborted(result, text)

    ## @brief Publishes feedback for a given goal
    ## @param  feedback Shared pointer to the feedback to publish
	def publish_feedback(self,feedback):
		self.current_goal.publish_feedback(feedback)


	def get_default_result(self):
		return self.action_server.ActionResultType()

    ## @brief Sets the status of the active goal to preempted
    ## @param  result An optional result to send back to any clients of the goal
	def set_preempted(self,result=None, text=""):
		if not result:
			result=self.get_default_result()
		with self.lock:
			rospy.logdebug("Setting the current goal as canceled")
			self.current_goal.set_canceled(result, text)

    ## @brief Allows users to register a callback to be invoked when a new goal is available
    ## @param cb The callback to be invoked
	def register_goal_callback(self,cb):
		if self.execute_callback:
			rospy.logwarn("Cannot call QueuedActionServer.register_goal_callback() because an executeCallback exists. Not going to register it.")
		else:
			self.goal_callback = cb

    ## @brief Allows users to register a callback to be invoked when a new preempt request is available
    ## @param cb The callback to be invoked
	def register_preempt_callback(self, cb):
		self.preempt_callback = cb
	

    ## @brief Explicitly start the action server, used it auto_start is set to false
	def start(self):
		self.action_server.start()


    ## @brief Callback for when the ActionServer receives a new goal and passes it on
	def internal_goal_callback(self, goal):

		self.execute_condition.acquire()
		try:

			rospy.logdebug("A new goal %shas been recieved by the Queued goal action server",goal.get_goal_id().id)

			if(self.goals_buf.empty()):
				self.new_goal = True
				self.next_goal = goal
				self.goals_buf.put(goal, timeout=1)
			else:
				
				self.goals_buf.put(goal, timeout=1)

			
			rospy.loginfo("Queued New Goal")

			if self.goal_callback:
				self.goal_callback()

			#rospy.loginfo("Goals List-----------------------------------------------")

			#for item in self.goals_buf:		

			#	rospy.loginfo("Goals Buffer%s" %item.get_goal_status())

			#rospy.loginfo("End of the Goals List-------------------------------------")

	#if the user has defined a goal callback, we'll call it now
			
	#Trigger runLoop to call execute()
			self.execute_condition.notify()
			self.execute_condition.release()
	
	
		except Exception, e:
			rospy.logerr("QueuedActionServer.internal_goal_callback - exception %s",str(e))
			self.execute_condition.release()
class QueuedActionServer:
    ## @brief Constructor for a QueuedActionServer
    ## @param name A name for the action server
    ## @param execute_cb Optional callback that gets called in a separate thread whenever
    ## a new goal is received, allowing users to have blocking callbacks.
    ## Adding an execute callback also deactivates the goalCallback.
    ## @param  auto_start A boolean value that tells the ActionServer wheteher or not to start publishing as soon as it comes up. THIS SHOULD ALWAYS BE SET TO FALSE TO AVOID RACE CONDITIONS and start() should be called after construction of the server.

    def __init__(self, name, ActionSpec, execute_cb=None, auto_start=True):

        self.new_goal = False
        self.preempt_request = False
        self.new_goal_preempt_request = False
        self.maxlen = 5

        #self.goals_buf = deque(maxlen=5)
        self.goals_buf = Queue.Queue(maxsize=self.maxlen)
        self.current_indexA = 0
        self.current_indexP = 0

        #self.maxlen = self.goals_buf.maxlen

        self.execute_callback = execute_cb
        self.goal_callback = None
        self.preempt_callback = None

        self.need_to_terminate = False
        self.terminate_mutex = threading.RLock()
        self.lock = threading.RLock()

        self.execute_condition = threading.Condition(self.lock)

        self.current_goal = ServerGoalHandle()
        self.next_goal = ServerGoalHandle()

        if self.execute_callback:
            self.execute_thread = threading.Thread(None, self.executeLoop)
            self.execute_thread.start()
        else:
            self.execute_thread = None

        #create the action server
        self.action_server = ActionServer(name, ActionSpec,
                                          self.internal_goal_callback,
                                          self.internal_preempt_callback,
                                          auto_start)

    def __del__(self):
        if hasattr(self, 'execute_callback') and self.execute_callback:
            with self.terminate_mutex:
                self.need_to_terminate = True

            assert (self.execute_thread)
            self.execute_thread.join()

## @brief Accepts a new goal when one is available The status of this
## goal is set to active upon acceptance, and the status of any
## previously active goal is set to preempted. Preempts received for the
## new goal between checking if isNewGoalAvailable or invokation of a
## goal callback and the acceptNewGoal call will not trigger a preempt
## callback.  This means, isPreemptReqauested should be called after
## accepting the goal even for callback-based implementations to make
## sure the new goal does not have a pending preempt request.
## @return A shared_ptr to the new goal.

    def accept_new_goal(self):

        with self.lock:
            if not self.new_goal or not self.next_goal.get_goal():
                rospy.logerr(
                    "Attempting to accept the next goal when a new goal is not available"
                )
                return None

            rospy.logdebug("Accepting a new goal")

            #accept the next goal
            self.current_goal = self.next_goal
            self.new_goal = False

            #set preempt to request to equal the preempt state of the new goal
            self.preempt_request = self.new_goal_preempt_request
            self.new_goal_preempt_request = False

            #set the status of the current goal to be active
            self.current_goal.set_accepted(
                "This goal has been accepted by the queued action server")

            return self.current_goal.get_goal()

## @brief Allows  polling implementations to query about the availability of a new goal
## @return True if a new goal is available, false otherwise

    def is_new_goal_available(self):
        return self.new_goal

## @brief Allows  polling implementations to query about preempt requests
## @return True if a preempt is requested, false otherwise

    def is_preempt_requested(self):
        return self.preempt_request

## @brief Allows  polling implementations to query about the status of the current goal
## @return True if a goal is active, false otherwise

    def is_active(self):
        if not self.current_goal.get_goal():
            return False

        status = self.current_goal.get_goal_status().status
        return status == actionlib_msgs.msg.GoalStatus.ACTIVE or status == actionlib_msgs.msg.GoalStatus.PREEMPTING

## @brief Sets the status of the active goal to succeeded
## @param  result An optional result to send back to any clients of the goal

    def set_succeeded(self, result=None, text=""):
        with self.lock:
            if not result:
                result = self.get_default_result()
            self.current_goal.set_succeeded(result, text)

## @brief Sets the status of the active goal to aborted
## @param  result An optional result to send back to any clients of the goal

    def set_aborted(self, result=None, text=""):
        with self.lock:
            if not result:
                result = self.get_default_result()
            self.current_goal.set_aborted(result, text)

## @brief Publishes feedback for a given goal
## @param  feedback Shared pointer to the feedback to publish

    def publish_feedback(self, feedback):
        self.current_goal.publish_feedback(feedback)

    def get_default_result(self):
        return self.action_server.ActionResultType()

## @brief Sets the status of the active goal to preempted
## @param  result An optional result to send back to any clients of the goal

    def set_preempted(self, result=None, text=""):
        if not result:
            result = self.get_default_result()
        with self.lock:
            rospy.logdebug("Setting the current goal as canceled")
            self.current_goal.set_canceled(result, text)

## @brief Allows users to register a callback to be invoked when a new goal is available
## @param cb The callback to be invoked

    def register_goal_callback(self, cb):
        if self.execute_callback:
            rospy.logwarn(
                "Cannot call QueuedActionServer.register_goal_callback() because an executeCallback exists. Not going to register it."
            )
        else:
            self.goal_callback = cb

## @brief Allows users to register a callback to be invoked when a new preempt request is available
## @param cb The callback to be invoked

    def register_preempt_callback(self, cb):
        self.preempt_callback = cb

## @brief Explicitly start the action server, used it auto_start is set to false

    def start(self):
        self.action_server.start()

## @brief Callback for when the ActionServer receives a new goal and passes it on

    def internal_goal_callback(self, goal):

        self.execute_condition.acquire()
        try:

            rospy.logdebug(
                "A new goal %shas been recieved by the Queued goal action server",
                goal.get_goal_id().id)

            if (self.goals_buf.empty()):
                self.new_goal = True
                self.next_goal = goal
                self.goals_buf.put(goal, timeout=1)
            else:

                self.goals_buf.put(goal, timeout=1)

            rospy.loginfo("Queued New Goal")

            if self.goal_callback:
                self.goal_callback()

            #rospy.loginfo("Goals List-----------------------------------------------")

            #for item in self.goals_buf:

            #	rospy.loginfo("Goals Buffer%s" %item.get_goal_status())

            #rospy.loginfo("End of the Goals List-------------------------------------")

    #if the user has defined a goal callback, we'll call it now

    #Trigger runLoop to call execute()
            self.execute_condition.notify()
            self.execute_condition.release()

        except Exception, e:
            rospy.logerr(
                "QueuedActionServer.internal_goal_callback - exception %s",
                str(e))
            self.execute_condition.release()