ssm_introspection.py

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#!/usr/bin/env python
#
# Copyright 2015 Airbus
# Copyright 2017 Fraunhofer Institute for Manufacturing Engineering and Automation (IPA)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from std_msgs.msg import String, Empty

import threading
import smach
import rospy
import airbus_ssm_core.msg
from ast import literal_eval


class ssmIntrospection():
    def __init__(self, state_machine, action_server = None):
        """Traverse the smach tree starting at root, and construct introspection
        proxies for getting and setting debug state."""

        self._state_machine = state_machine
        self._as = action_server
        self._tree_view = {}
        self._server_name = rospy.get_param('ssm_server_name', '/ssm')
        self._update_pub = rospy.Publisher(self._server_name + "/ssm_status", String, queue_size = 1)
        self._request_update = rospy.Subscriber(self._server_name + "/status_request", Empty, self._status_request_cb, queue_size = 1)

    def start(self):
        # Construct proxies
        self._state_machine._create_tree_view()
        self.construct(self._state_machine,"ROOT")
    
    def stop(self):
        self._request_update.unregister()
        self._tree_view = {}
        

    def construct(self, state, _key):
        """Recursively construct tree view."""
        self._tree_view[_key] = state.get_tree_view()
        state.register_tree_view_cb(self._update_tree_view_cb)
        # Get a list of children that are also containers
        for (label, child) in state.get_children().items():
            # If this is also a container, recurse into it
            if isinstance(child, smach.container.Container):
                child._create_tree_view()
                self.construct(child, label)
                
    def _update_tree_view_cb(self, *args, **kwargs):
        self._update_pub.publish(str(self._tree_view))
        if(self._as is not None):
            feedback = airbus_ssm_core.msg.SSMFeedback()
            feedback.current_active_states = str(self._tree_view) 
            self._as.publish_feedback(feedback)
        
    def _status_request_cb(self, msg):
        self._update_pub.publish(str(self._tree_view))