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

  1  # -*- coding: utf-8 -*- 
  2   
  3  # Copyright (C) 2010-2013 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 if self.client_instance.get_session_of_session_name(session_name, return_object=True, match_profile_name=profile_name).is_running(): 156 if control_session is not None and not control_session.has_session_died(): 157 self.x2go_listsessions_cache[profile_name]['mounts'].update(control_session.list_mounts(session_name)) 158 except (x2go_exceptions.X2GoControlSessionException, AttributeError), e: 159 if profile_name in self.x2go_listsessions_cache.keys(): 160 del self.x2go_listsessions_cache[profile_name] 161 self.protected = False 162 raise x2go_exceptions.X2GoControlSessionException 163 except x2go_exceptions.X2GoTimeOutException: 164 pass 165 except KeyError: 166 pass
167
168 - def _update_desktops(self, profile_name, control_session):
169 """\ 170 Update session lists of L{X2GoListSessionsCache} for session profile C{profile_name}. 171 172 @param profile_name: name of profile to update 173 @type profile_name: C{str} 174 @param control_session: X2Go control session instance 175 @type control_session: C{obj} 176 177 @raise X2GoControlSessionException: if the control session's C{list_desktop} method fails 178 """ 179 try: 180 if control_session is not None and not control_session.has_session_died(): 181 self.x2go_listsessions_cache[profile_name]['desktops'] = control_session.list_desktops() 182 except (x2go_exceptions.X2GoControlSessionException, AttributeError), e: 183 if profile_name in self.x2go_listsessions_cache.keys(): 184 del self.x2go_listsessions_cache[profile_name] 185 self.protected = False 186 raise x2go_exceptions.X2GoControlSessionException 187 except x2go_exceptions.X2GoTimeOutException: 188 pass 189 except KeyError: 190 pass
191
192 - def _update_sessions(self, profile_name, control_session):
193 """\ 194 Update desktop list of L{X2GoListSessionsCache} for session profile C{profile_name}. 195 196 @param profile_name: name of profile to update 197 @type profile_name: C{str} 198 199 @raise X2GoControlSessionException: if the control session's C{list_sessions} method fails 200 """ 201 try: 202 if control_session is not None and not control_session.has_session_died(): 203 self.x2go_listsessions_cache[profile_name]['sessions'] = control_session.list_sessions() 204 except (x2go_exceptions.X2GoControlSessionException, AttributeError), e: 205 if profile_name in self.x2go_listsessions_cache.keys(): 206 del self.x2go_listsessions_cache[profile_name] 207 self.protected = False 208 raise x2go_exceptions.X2GoControlSessionException 209 except KeyError: 210 pass
211
212 - def list_sessions(self, session_uuid):
213 """\ 214 Retrieve a session list from the current cache content of L{X2GoListSessionsCache} 215 for a given L{X2GoSession} instance (specified by its unique session UUID). 216 217 @param session_uuid: unique identifier of session to query cache for 218 @type session_uuid: C{str} 219 220 @return: a data object containing available session information 221 @rtype: C{X2GoServerSessionList*} instance (or C{None}) 222 223 """ 224 profile_name = self.client_instance.get_session_profile_name(session_uuid) 225 if self.is_cached(session_uuid=session_uuid): 226 return self.x2go_listsessions_cache[profile_name]['sessions'] 227 else: 228 return None
229
230 - def list_desktops(self, session_uuid):
231 """\ 232 Retrieve a list of available desktop sessions from the current cache content of 233 L{X2GoListSessionsCache} for a given L{X2GoSession} instance (specified by its 234 unique session UUID). 235 236 @param session_uuid: unique identifier of session to query cache for 237 @type session_uuid: C{str} 238 239 @return: a list of strings representing X2Go desktop sessions available for sharing 240 @rtype: C{list} (or C{None}) 241 242 """ 243 profile_name = self.client_instance.get_session_profile_name(session_uuid) 244 if self.is_cached(session_uuid=session_uuid): 245 return self.x2go_listsessions_cache[profile_name]['desktops'] 246 else: 247 return None
248
249 - def list_mounts(self, session_uuid):
250 """\ 251 Retrieve a list of mounted client shares from the current cache content of 252 L{X2GoListSessionsCache} for a given L{X2GoSession} instance (specified by its 253 unique session UUID). 254 255 @param session_uuid: unique identifier of session to query cache for 256 @type session_uuid: C{str} 257 258 @return: a list of strings representing mounted client shares 259 @rtype: C{list} (or C{None}) 260 261 """ 262 profile_name = self.client_instance.get_session_profile_name(session_uuid) 263 if self.is_cached(session_uuid=session_uuid): 264 return self.x2go_listsessions_cache[profile_name]['mounts'] 265 else: 266 return None
267
268 - def is_cached(self, profile_name=None, session_uuid=None, cache_type=None):
269 """\ 270 Check if session information is cached. 271 272 @param profile_name: name of profile to update 273 @type profile_name: C{str} 274 @param session_uuid: unique identifier of session to query cache for 275 @type session_uuid: C{str} 276 277 @return: C{True} if session information is cached 278 @rtype: C{bool} 279 280 """ 281 if profile_name is None and session_uuid and self.client_instance: 282 try: 283 profile_name = self.client_instance.get_session_profile_name(session_uuid) 284 except x2go_exceptions.X2GoSessionRegistryException: 285 raise x2go_exceptions.X2GoSessionCacheException("requested session UUID is not valid anymore") 286 _is_profile_cached = self.x2go_listsessions_cache.has_key(profile_name) 287 _is_cache_type_cached = _is_profile_cached and self.x2go_listsessions_cache[profile_name].has_key(cache_type) 288 if cache_type is None: 289 return _is_profile_cached 290 else: 291 return _is_cache_type_cached
292