Package x2go :: Module cache
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Source Code for Module x2go.cache

  1  # -*- coding: utf-8 -*- 
  2   
  3  # Copyright (C) 2010-2012 by Mike Gabriel <mike.gabriel@das-netzwerkteam.de> 
  4  # 
  5  # Python X2Go is free software; you can redistribute it and/or modify 
  6  # it under the terms of the GNU Affero General Public License as published by 
  7  # the Free Software Foundation; either version 3 of the License, or 
  8  # (at your option) any later version. 
  9  # 
 10  # Python X2Go is distributed in the hope that it will be useful, 
 11  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
 12  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 13  # GNU Affero General Public License for more details. 
 14  # 
 15  # You should have received a copy of the GNU Affero General Public License 
 16  # along with this program; if not, write to the 
 17  # Free Software Foundation, Inc., 
 18  # 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. 
 19   
 20  """\ 
 21  X2goListSessionCache class - caching X2Go session information. 
 22   
 23  """ 
 24  __NAME__ = 'x2gocache-pylib' 
 25   
 26  # modules 
 27  import copy 
 28  import gevent 
 29   
 30  # Python X2Go modules 
 31  import log 
 32  import x2go_exceptions 
 33   
34 -class X2goListSessionsCache(object):
35 """\ 36 For non-blocking operations in client applications using Python X2Go, it is 37 recommended to enable the L{X2goListSessionsCache}. This can be done by calling 38 the constructor of the L{X2goClient} class. 39 40 The session list and desktop cache gets updated in regular intervals by a threaded 41 L{X2goSessionGuardian} instance. For the session list and desktop list update, the 42 X2Go server commands C{x2golistsessions} and C{x2godesktopsessions} are called and 43 the command's stdout is cached in the session list cache. 44 45 Whenever your client application needs access to either the server's session list 46 or the server's desktop list the session cache is queried instead. This assures that 47 the server's session/desktop list is available without delay, even on slow internet 48 connections. 49 50 """ 51 x2go_listsessions_cache = {} 52
53 - def __init__(self, client_instance, logger=None, loglevel=log.loglevel_DEFAULT):
54 """\ 55 @param client_instance: the L{X2goClient} instance that uses this L{X2goListSessionsCache} 56 @type client_instance: C{obj} 57 @param logger: you can pass an L{X2goLogger} object to the L{X2goListSessionsCache} constructor 58 @type logger: C{obj} 59 @param loglevel: if no L{X2goLogger} object has been supplied a new one will be 60 constructed with the given loglevel 61 @type loglevel: C{int} 62 63 """ 64 self.x2go_listsessions_cache = {} 65 self.last_listsessions_cache = {} 66 self.protected = False 67 68 if logger is None: 69 self.logger = log.X2goLogger(loglevel=loglevel) 70 else: 71 self.logger = copy.deepcopy(logger) 72 self.logger.tag = __NAME__ 73 74 self.client_instance = client_instance
75
76 - def delete(self, profile_name):
77 """\ 78 Remove session list from cache for a given profile. 79 80 @param profile_name: name of profile to operate on 81 @type profile_name: C{str} 82 83 """ 84 while self.protected: 85 gevent.sleep(.1) 86 try: del self.x2go_listsessions_cache[profile_name] 87 except KeyError: pass
88
89 - def check_cache(self):
90 """\ 91 Check if session list cache elements are still valid (i.e. if all corresponding 92 session profiles are still connected). If not so, remove invalid cache entries from 93 the session list cache. 94 95 """ 96 for profile_name in self.x2go_listsessions_cache.keys(): 97 if profile_name not in self.client_instance.client_connected_profiles(return_profile_names=True): 98 del self.x2go_listsessions_cache[profile_name]
99
100 - def update_all(self, update_sessions=True, update_desktops=False):
101 """\ 102 Update L{X2goListSessionsCache} for all connected session profiles. 103 104 @param update_sessions: cache recent session lists from all connected servers 105 @type update_sessions: C{bool} 106 @param update_desktops: cache recent desktop lists from all connected servers 107 @type update_desktops: C{bool} 108 109 """ 110 for profile_name in self.client_instance.client_connected_profiles(return_profile_names=True): 111 self.update(profile_name, update_sessions=update_sessions, update_desktops=update_desktops) 112 113 self.check_cache()
114
115 - def update(self, profile_name, update_sessions=True, update_desktops=False, update_mounts=False):
116 """\ 117 Update L{X2goListSessionsCache} (i.e. session/desktops) for session profile C{profile_name}. 118 119 @param profile_name: name of profile to update 120 @type profile_name: C{str} 121 @param update_sessions: cache recent session list from server 122 @type update_sessions: C{bool} 123 @param update_desktops: cache recent desktop list from server 124 @type update_desktops: C{bool} 125 @param update_mounts: cache list of client-side mounts on server 126 @type update_mounts: C{bool} 127 128 """ 129 self.protected = True 130 self.last_listsessions_cache = copy.deepcopy(self.x2go_listsessions_cache) 131 control_session = self.client_instance.client_control_session_of_profile_name(profile_name) 132 if not self.x2go_listsessions_cache.has_key(profile_name): 133 self.x2go_listsessions_cache[profile_name] = {'sessions': None, 'desktops': None, 'mounts': {}, } 134 if update_sessions: 135 self._update_sessions(profile_name, control_session) 136 if update_desktops: 137 self._update_desktops(profile_name, control_session) 138 if update_mounts: 139 self._update_mounts(profile_name, control_session) 140 self.protected = False
141
142 - def _update_mounts(self, profile_name, control_session):
143 """\ 144 Update mounts list of L{X2goListSessionsCache} for session profile C{profile_name}. 145 146 @param profile_name: name of profile to update 147 @type profile_name: C{str} 148 149 @raise X2goControlSessionException: if the control session's C{list_mounts} method fails 150 """ 151 try: 152 self.x2go_listsessions_cache[profile_name]['mounts'] = {} 153 if self.x2go_listsessions_cache[profile_name]['sessions']: 154 for session_name in self.x2go_listsessions_cache[profile_name]['sessions']: 155 self.x2go_listsessions_cache[profile_name]['mounts'].update(control_session.list_mounts(session_name)) 156 except x2go_exceptions.X2goControlSessionException, e: 157 if profile_name in self.x2go_listsessions_cache.keys(): 158 del self.x2go_listsessions_cache[profile_name] 159 self.protected = False 160 raise e 161 except x2go_exceptions.X2goTimeOutException: 162 pass
163
164 - def _update_desktops(self, profile_name, control_session):
165 """\ 166 Update session lists of L{X2goListSessionsCache} for session profile C{profile_name}. 167 168 @param profile_name: name of profile to update 169 @type profile_name: C{str} 170 @param control_session: X2Go control session instance 171 @type control_session: C{obj} 172 173 @raise X2goControlSessionException: if the control session's C{list_desktop} method fails 174 """ 175 try: 176 self.x2go_listsessions_cache[profile_name]['desktops'] = control_session.list_desktops() 177 except x2go_exceptions.X2goControlSessionException, e: 178 if profile_name in self.x2go_listsessions_cache.keys(): 179 del self.x2go_listsessions_cache[profile_name] 180 self.protected = False 181 raise e 182 except x2go_exceptions.X2goTimeOutException: 183 pass
184
185 - def _update_sessions(self, profile_name, control_session):
186 """\ 187 Update desktop list of L{X2goListSessionsCache} for session profile C{profile_name}. 188 189 @param profile_name: name of profile to update 190 @type profile_name: C{str} 191 192 @raise X2goControlSessionException: if the control session's C{list_sessions} method fails 193 """ 194 try: 195 if control_session is not None: 196 self.x2go_listsessions_cache[profile_name]['sessions'] = control_session.list_sessions() 197 except x2go_exceptions.X2goControlSessionException, e: 198 if profile_name in self.x2go_listsessions_cache.keys(): 199 del self.x2go_listsessions_cache[profile_name] 200 self.protected = False 201 raise e
202
203 - def list_sessions(self, session_uuid):
204 """\ 205 Retrieve a session list from the current cache content of L{X2goListSessionsCache} 206 for a given L{X2goSession} instance (specified by its unique session UUID). 207 208 @param session_uuid: unique identifier of session to query cache for 209 @type session_uuid: C{str} 210 211 @return: a data object containing available session information 212 @rtype: C{X2goServerSessionList*} instance (or C{None}) 213 214 """ 215 profile_name = self.client_instance.get_session_profile_name(session_uuid) 216 if self.is_cached(session_uuid=session_uuid): 217 return self.x2go_listsessions_cache[profile_name]['sessions'] 218 else: 219 return None
220
221 - def list_desktops(self, session_uuid):
222 """\ 223 Retrieve a list of available desktop sessions from the current cache content of 224 L{X2goListSessionsCache} for a given L{X2goSession} instance (specified by its 225 unique session UUID). 226 227 @param session_uuid: unique identifier of session to query cache for 228 @type session_uuid: C{str} 229 230 @return: a list of strings representing X2Go desktop sessions available for sharing 231 @rtype: C{list} (or C{None}) 232 233 """ 234 profile_name = self.client_instance.get_session_profile_name(session_uuid) 235 if self.is_cached(session_uuid=session_uuid): 236 return self.x2go_listsessions_cache[profile_name]['desktops'] 237 else: 238 return None
239
240 - def list_mounts(self, session_uuid):
241 """\ 242 Retrieve a list of mounted client shares from the current cache content of 243 L{X2goListSessionsCache} for a given L{X2goSession} instance (specified by its 244 unique session UUID). 245 246 @param session_uuid: unique identifier of session to query cache for 247 @type session_uuid: C{str} 248 249 @return: a list of strings representing mounted client shares 250 @rtype: C{list} (or C{None}) 251 252 """ 253 profile_name = self.client_instance.get_session_profile_name(session_uuid) 254 if self.is_cached(session_uuid=session_uuid): 255 return self.x2go_listsessions_cache[profile_name]['mounts'] 256 else: 257 return None
258
259 - def is_cached(self, profile_name=None, session_uuid=None, cache_type=None):
260 """\ 261 Check if session information is cached. 262 263 @param profile_name: name of profile to update 264 @type profile_name: C{str} 265 @param session_uuid: unique identifier of session to query cache for 266 @type session_uuid: C{str} 267 268 @return: C{True} if session information is cached 269 @rtype: C{bool} 270 271 """ 272 if profile_name is None and session_uuid and self.client_instance: 273 try: 274 profile_name = self.client_instance.get_session_profile_name(session_uuid) 275 except x2go_exceptions.X2goSessionRegistryException: 276 raise x2go_exceptions.X2goSessionCacheException("requested session UUID is not valid anymore") 277 _is_profile_cached = self.x2go_listsessions_cache.has_key(profile_name) 278 _is_cache_type_cached = _is_profile_cached and self.x2go_listsessions_cache[profile_name].has_key(cache_type) 279 if cache_type is None: 280 return _is_profile_cached 281 else: 282 return _is_cache_type_cached
283