param_updater.py

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# Author: Isaac Saito, Ze'ev Klapow

import threading
import time

import rospy

from . import logging


class ParamUpdater(threading.Thread):
    '''
    Using dynamic_reconfigure that is passed in __init__, this thread updates
    the Dynamic Reconfigure server's value.

    This class works for a single element in a single parameter.
    '''

    #TODO: Modify variable names to the ones that's more intuitive.

    def __init__(self, reconf):
        """
        :type reconf: dynamic_reconfigure
        """
        super(ParamUpdater, self).__init__()
        self.setDaemon(True)

        self._reconf = reconf
        self._condition_variable = threading.Condition()
        self._configs_pending = {}
        self._timestamp_last_pending = None
        self._stop_flag = False

    def run(self):
        _timestamp_last_commit = None

        logging.debug(' ParamUpdater started')

        while not self._stop_flag:
            if self._timestamp_last_pending is None or _timestamp_last_commit >= self._timestamp_last_pending:
                    with self._condition_variable:
                        logging.debug(' ParamUpdater loop 1.1')
                        self._condition_variable.wait()
                        logging.debug(' ParamUpdater loop 1.2')
            logging.debug(' ParamUpdater loop 2')

            if self._stop_flag:
                return

            _timestamp_last_commit = time.time()
            configs_tobe_updated = self._configs_pending.copy()
            self._configs_pending = {}

            logging.debug('  run last_commit={}, last_pend={}'.format(
                         _timestamp_last_commit, self._timestamp_last_pending))

            try:
                self._reconf.update_configuration(configs_tobe_updated)
            except rospy.ServiceException as ex:
                logging.debug('Could not update configs due to {}'.format(
                                                                     ex.value))
            except Exception as exc:
                raise exc

    def update(self, config):
        with self._condition_variable:
            for name, value in config.items():
                self._configs_pending[name] = value

            self._timestamp_last_pending = time.time()

            self._condition_variable.notify()

    def stop(self):
        self._stop_flag = True
        with self._condition_variable:
            self._condition_variable.notify()