monitor.py

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#! /usr/bin/env python
# -*- coding: utf-8 -*-

# Software License Agreement (BSD)
#
#  file      @monitor.py
#  authors   Mike Purvis <mpurvis@clearpathrobotics.com>
#  copyright Copyright (c) 2012, Clearpath Robotics, Inc., All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification, are permitted provided that
# the following conditions are met:
#  * Redistributions of source code must retain the above copyright notice, this list of conditions and the
#    following disclaimer.
#  * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
#    following disclaimer in the documentation and/or other materials provided with the distribution.
#  * Neither the name of Clearpath Robotics nor the names of its contributors may be used to endorse or promote
#    products derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WAR-
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import rospy
import threading


class Monitor(threading.Thread):
    def __init__(self, ports):
        super(Monitor, self).__init__()
        self.ports = ports
        self.finish = threading.Event()

    def run(self):
        while not self.finish:
            rospy.sleep(1.0)
            for name, port in ports.items():
                if not port.is_alive():
                    rospy.logerr("Port %s thread died. Signalling node shutdown." % name)
                    rospy.signal_shutdown("Node lost thread.")