baseimage-tutorial-framework/lib/tfw/components/directory_monitoring_event_handler.py

# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
# All Rights Reserved. See LICENSE file for details.

from os.path import isdir, exists

from tfw.components.directory_monitor import DirectoryMonitor
from tfw.event_handler_base import TriggerlessEventHandler
from tfw.config.logs import logging

LOG = logging.getLogger(__name__)


class DirectoryMonitoringEventHandler(TriggerlessEventHandler):
    def __init__(self, key, directory):
        super().__init__(key)
        self._directory = directory
        self._monitor = None
        self.reload_monitor()
        self.commands = {'pause':     self.pause,
                         'resume':    self.resume,
                         'ignore':    self.ignore,
                         'selectdir': self.selectdir}

    @property
    def directory(self):
        return self._directory

    @directory.setter
    def directory(self, directory):
        if not exists(directory) or not isdir(directory):
            raise EnvironmentError('No such directory!')
        self._directory = directory

    @property
    def monitor(self):
        return self._monitor

    def reload_monitor(self):
        if self._monitor:
            try:
                self._monitor.stop()
            except KeyError:
                logging.debug('Working directory was removed – ignoring...')
        self._monitor = DirectoryMonitor(self._directory)
        self._monitor.watch()   # This runs on a separate thread

    def handle_event(self, key, message):
        try:
            message['data'] = self.commands[message['data']['command']](message['data'])
            return message
        except KeyError:
            LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)

    def pause(self, data):
        self.monitor.pause()
        return data

    def resume(self, data):
        self.monitor.resume()
        return data

    def ignore(self, data):
        self.monitor.ignore += data['ignore']
        return data

    def selectdir(self, data):
        try:
            self.directory = data['directory']
            self.reload_monitor()
            return data
        except EnvironmentError:
            LOG.error('Failed to switch directory!')

    def cleanup(self):
        self.monitor.stop()