#!/usr/bin/env python # # Copyright (C) 2016 GNS3 Technologies Inc. # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . from contextlib import contextmanager from gns3server.utils.notification_queue import NotificationQueue class NotificationManager: """ Manage the notification queue where the controller will connect to get notifications from computes """ def __init__(self): self._listeners = set() @contextmanager def queue(self): """ Get a queue of notifications Use it with Python with """ queue = NotificationQueue() self._listeners.add(queue) try: yield queue finally: self._listeners.remove(queue) def emit(self, action, event, **kwargs): """ Send an event to all the client listening for notifications :param action: Action name :param event: Event to send :param kwargs: Add this meta to the notification (project_id for example) """ for listener in self._listeners: listener.put_nowait((action, event, kwargs)) @staticmethod def reset(): NotificationManager._instance = None @staticmethod def instance(): """ Singleton to return only on instance of NotificationManager. :returns: instance of NotificationManager """ if not hasattr(NotificationManager, '_instance') or NotificationManager._instance is None: NotificationManager._instance = NotificationManager() return NotificationManager._instance