Source code for x2go.cache

# -*- coding: utf-8 -*-

# Copyright (C) 2010-2023 by Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
#
# Python X2Go is free software; you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# Python X2Go 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program; if not, write to the
# Free Software Foundation, Inc.,
# 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.

"""\
X2GoListSessionCache class - caching X2Go session information.

"""
__NAME__ = 'x2gocache-pylib'

__package__ = 'x2go'
__name__    = 'x2go.cache'

# modules
import copy
import gevent

# Python X2Go modules
from . import log
from . import x2go_exceptions

[docs] class X2GoListSessionsCache(object): """\ For non-blocking operations in client applications using Python X2Go, it is recommended to enable the :class:`x2go.cache.X2GoListSessionsCache`. This can be done by calling the constructor of the :class:`x2go.client.X2GoClient` class. The session list and desktop cache gets updated in regular intervals by a threaded :class:`x2go.guardian.X2GoSessionGuardian` instance. For the session list and desktop list update, the X2Go server commands ``x2golistsessions`` and ``x2godesktopsessions`` are called and the command's stdout is cached in the session list cache. Whenever your client application needs access to either the server's session list or the server's desktop list the session cache is queried instead. This assures that the server's session/desktop list is available without delay, even on slow internet connections. """ x2go_listsessions_cache = {} def __init__(self, client_instance, logger=None, loglevel=log.loglevel_DEFAULT): """\ :param client_instance: the :class:`x2go.client.X2GoClient` instance that uses this :class:`x2go.cache.X2GoListSessionsCache` :type client_instance: ``obj`` :param logger: you can pass an :class:`x2go.log.X2GoLogger` object to the :class:`x2go.cache.X2GoListSessionsCache` constructor :type logger: ``obj`` :param loglevel: if no :class:`x2go.log.X2GoLogger` object has been supplied a new one will be constructed with the given loglevel :type loglevel: ``int`` """ self.x2go_listsessions_cache = {} self.last_listsessions_cache = {} self.protected = False if logger is None: self.logger = log.X2GoLogger(loglevel=loglevel) else: self.logger = copy.deepcopy(logger) self.logger.tag = __NAME__ self.client_instance = client_instance
[docs] def delete(self, profile_name): """\ Remove session list from cache for a given profile. :param profile_name: name of profile to operate on :type profile_name: ``str`` """ while self.protected: gevent.sleep(.1) try: del self.x2go_listsessions_cache[profile_name] except KeyError: pass
[docs] def check_cache(self): """\ Check if session list cache elements are still valid (i.e. if all corresponding session profiles are still connected). If not so, remove invalid cache entries from the session list cache. """ for profile_name in list(self.x2go_listsessions_cache.keys()): if profile_name not in self.client_instance.client_connected_profiles(return_profile_names=True): del self.x2go_listsessions_cache[profile_name]
[docs] def update_all(self, update_sessions=True, update_desktops=False): """\ Update :class:`x2go.cache.X2GoListSessionsCache` for all connected session profiles. :param update_sessions: cache recent session lists from all connected servers (Default value = True) :type update_sessions: ``bool`` :param update_desktops: cache recent desktop lists from all connected servers (Default value = False) :type update_desktops: ``bool`` """ for profile_name in self.client_instance.client_connected_profiles(return_profile_names=True): self.update(profile_name, update_sessions=update_sessions, update_desktops=update_desktops) self.check_cache()
[docs] def update(self, profile_name, update_sessions=True, update_desktops=False, update_mounts=False): """\ Update :class:`x2go.cache.X2GoListSessionsCache` (i.e. session/desktops) for session profile ``profile_name``. :param profile_name: name of profile to update :type profile_name: ``str`` :param update_sessions: cache recent session list from server (Default value = True) :type update_sessions: ``bool`` :param update_desktops: cache recent desktop list from server (Default value = False) :type update_desktops: ``bool`` :param update_mounts: cache list of client-side mounts on server (Default value = False) :type update_mounts: ``bool`` """ self.protected = True self.last_listsessions_cache = copy.deepcopy(self.x2go_listsessions_cache) control_session = self.client_instance.client_control_session_of_profile_name(profile_name) if profile_name not in self.x2go_listsessions_cache: self.x2go_listsessions_cache[profile_name] = {'sessions': None, 'desktops': None, 'mounts': {}, } if update_sessions: self._update_sessions(profile_name, control_session) if update_desktops: self._update_desktops(profile_name, control_session) if update_mounts: self._update_mounts(profile_name, control_session) self.protected = False
def _update_mounts(self, profile_name, control_session): """\ Update mounts list of :class:`x2go.cache.X2GoListSessionsCache` for session profile ``profile_name``. :param profile_name: name of profile to update :type profile_name: ``str`` :param control_session: X2Go control session instance :raises X2GoControlSessionException: if the control session's ``list_mounts`` method fails """ try: self.x2go_listsessions_cache[profile_name]['mounts'] = {} if self.x2go_listsessions_cache[profile_name]['sessions']: for session_name in self.x2go_listsessions_cache[profile_name]['sessions']: session = self.client_instance.get_session_of_session_name(session_name, return_object=True, match_profile_name=profile_name) if session is not None and session.is_running(): if control_session is not None and not control_session.has_session_died(): self.x2go_listsessions_cache[profile_name]['mounts'].update(control_session.list_mounts(session_name)) except (x2go_exceptions.X2GoControlSessionException, AttributeError) as e: if profile_name in list(self.x2go_listsessions_cache.keys()): del self.x2go_listsessions_cache[profile_name] self.protected = False raise x2go_exceptions.X2GoControlSessionException(str(e)) except x2go_exceptions.X2GoTimeOutException: pass except KeyError: pass def _update_desktops(self, profile_name, control_session): """\ Update session lists of :class:`x2go.cache.X2GoListSessionsCache` for session profile ``profile_name``. :param profile_name: name of profile to update :type profile_name: ``str`` :param control_session: X2Go control session instance :type control_session: ``obj`` :raises X2GoControlSessionException: if the control session's ``list_desktop`` method fails """ try: if control_session is not None and not control_session.has_session_died(): self.x2go_listsessions_cache[profile_name]['desktops'] = control_session.list_desktops() except (x2go_exceptions.X2GoControlSessionException, AttributeError) as e: if profile_name in list(self.x2go_listsessions_cache.keys()): del self.x2go_listsessions_cache[profile_name] self.protected = False raise x2go_exceptions.X2GoControlSessionException(str(e)) except x2go_exceptions.X2GoTimeOutException: pass except KeyError: pass def _update_sessions(self, profile_name, control_session): """\ Update desktop list of :class:`x2go.cache.X2GoListSessionsCache` for session profile ``profile_name``. :param profile_name: name of profile to update :type profile_name: ``str`` :param control_session: X2Go control session instance :type control_session: ``obj`` :raises X2GoControlSessionException: if the control session's ``list_sessions`` method fails """ try: if control_session is not None and not control_session.has_session_died(): self.x2go_listsessions_cache[profile_name]['sessions'] = control_session.list_sessions() except (x2go_exceptions.X2GoControlSessionException, AttributeError) as e: if profile_name in list(self.x2go_listsessions_cache.keys()): del self.x2go_listsessions_cache[profile_name] self.protected = False raise x2go_exceptions.X2GoControlSessionException(str(e)) except KeyError: pass
[docs] def list_sessions(self, session_uuid): """\ Retrieve a session list from the current cache content of :class:`x2go.cache.X2GoListSessionsCache` for a given :class:`x2go.session.X2GoSession` instance (specified by its unique session UUID). :param session_uuid: unique identifier of session to query cache for :type session_uuid: ``str`` :returns: a data object containing available session information :rtype: ``X2GoServerSessionList*`` instance (or ``None``) """ profile_name = self.client_instance.get_session_profile_name(session_uuid) if self.is_cached(session_uuid=session_uuid): return self.x2go_listsessions_cache[profile_name]['sessions'] else: return None
[docs] def list_desktops(self, session_uuid): """\ Retrieve a list of available desktop sessions from the current cache content of :class:`x2go.cache.X2GoListSessionsCache` for a given :class:`x2go.session.X2GoSession` instance (specified by its unique session UUID). :param session_uuid: unique identifier of session to query cache for :type session_uuid: ``str`` :returns: a list of strings representing X2Go desktop sessions available for sharing :rtype: ``list`` (or ``None``) """ profile_name = self.client_instance.get_session_profile_name(session_uuid) if self.is_cached(session_uuid=session_uuid): return self.x2go_listsessions_cache[profile_name]['desktops'] else: return None
[docs] def list_mounts(self, session_uuid): """\ Retrieve a list of mounted client shares from the current cache content of :class:`x2go.cache.X2GoListSessionsCache` for a given :class:`x2go.session.X2GoSession` instance (specified by its unique session UUID). :param session_uuid: unique identifier of session to query cache for :type session_uuid: ``str`` :returns: a list of strings representing mounted client shares :rtype: ``list`` (or ``None``) """ profile_name = self.client_instance.get_session_profile_name(session_uuid) if self.is_cached(session_uuid=session_uuid): return self.x2go_listsessions_cache[profile_name]['mounts'] else: return None
[docs] def is_cached(self, profile_name=None, session_uuid=None, cache_type=None): """\ Check if session information is cached. :param profile_name: name of profile to update (Default value = None) :type profile_name: ``str`` :param session_uuid: unique identifier of session to query cache for (Default value = None) :type session_uuid: ``str`` :param cache_type: cache type (e.g. 'mounts', 'desktops', 'sessions') (Default value = None) :type cache_type: ``str`` :returns: ``True`` if session information is cached :rtype: ``bool`` """ if profile_name is None and session_uuid and self.client_instance: try: profile_name = self.client_instance.get_session_profile_name(session_uuid) except x2go_exceptions.X2GoSessionRegistryException: raise x2go_exceptions.X2GoSessionCacheException("requested session UUID is not valid anymore") _is_profile_cached = profile_name in self.x2go_listsessions_cache _is_cache_type_cached = _is_profile_cached and cache_type in self.x2go_listsessions_cache[profile_name] if cache_type is None: return _is_profile_cached else: return _is_cache_type_cached