mirror of
https://github.com/GNS3/gns3-server.git
synced 2025-01-19 07:53:47 +02:00
120 lines
3.6 KiB
Python
120 lines
3.6 KiB
Python
#!/usr/bin/env python
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#
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# Copyright (C) 2016 GNS3 Technologies Inc.
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import asyncio
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import psutil
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import json
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from contextlib import contextmanager
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class NotificationQueue(asyncio.Queue):
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"""
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Queue returned by the notification manager.
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"""
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def __init__(self):
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super().__init__()
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self._first = True
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@asyncio.coroutine
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def get(self, timeout):
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"""
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When timeout is expire we send a ping notification with server informations
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"""
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# At first get we return a ping so the client receive immediately data
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if self._first:
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self._first = False
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return ("ping", self._getPing(), {})
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try:
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(action, msg, kwargs) = yield from asyncio.wait_for(super().get(), timeout)
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except asyncio.futures.TimeoutError:
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return ("ping", self._getPing(), {})
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return (action, msg, kwargs)
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def _getPing(self):
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"""
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Return the content of the ping notification
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"""
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msg = {}
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# Non blocking call in order to get cpu usage. First call will return 0
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msg["cpu_usage_percent"] = psutil.cpu_percent(interval=None)
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msg["memory_usage_percent"] = psutil.virtual_memory().percent
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return msg
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@asyncio.coroutine
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def get_json(self, timeout):
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"""
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Get a message as a JSON
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"""
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(action, msg, kwargs) = yield from self.get(timeout)
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if hasattr(msg, "__json__"):
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msg = {"action": action, "event": msg.__json__()}
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else:
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msg = {"action": action, "event": msg}
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msg.update(kwargs)
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return json.dumps(msg, sort_keys=True)
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class NotificationManager:
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"""
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Manage the notification queue where the controller
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will connect to get notifications from hypervisors
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"""
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def __init__(self):
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self._listeners = set()
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@contextmanager
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def queue(self):
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"""
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Get a queue of notifications
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Use it with Python with
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"""
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queue = NotificationQueue()
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self._listeners.add(queue)
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yield queue
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self._listeners.remove(queue)
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def emit(self, action, event, **kwargs):
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"""
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Send an event to all the client listening for notifications
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:param action: Action name
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:param event: Event to send
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:param kwargs: Add this meta to the notif (project_id for example)
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"""
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for listener in self._listeners:
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listener.put_nowait((action, event, kwargs))
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@staticmethod
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def reset():
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NotificationManager._instance = None
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@staticmethod
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def instance():
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"""
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Singleton to return only on instance of NotificationManager.
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:returns: instance of NotificationManager
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"""
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if not hasattr(NotificationManager, '_instance') or NotificationManager._instance is None:
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NotificationManager._instance = NotificationManager()
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return NotificationManager._instance
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