Package x2go :: Package backends :: Package proxy :: Module base
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Source Code for Module x2go.backends.proxy.base

  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  X2goProxyBASE class - proxying your connection through NX3 and others. 
 22   
 23  """ 
 24  __NAME__ = 'x2goproxy-pylib' 
 25   
 26  # modules 
 27  import gevent 
 28  import os 
 29  import copy 
 30  import threading 
 31  import socket 
 32   
 33  # Python X2Go modules 
 34  import x2go.forward as forward 
 35  import x2go.log as log 
 36  import x2go.utils as utils 
 37  import x2go.x2go_exceptions as x2go_exceptions 
 38   
 39  from x2go.defaults import X2GOCLIENT_OS as _X2GOCLIENT_OS 
 40  if _X2GOCLIENT_OS in ("Windows"): 
 41      import subprocess 
 42  else: 
 43      import x2go.gevent_subprocess as subprocess 
 44      from x2go.x2go_exceptions import WindowsError 
 45   
 46  from x2go.defaults import LOCAL_HOME as _LOCAL_HOME 
 47  from x2go.defaults import X2GO_SESSIONS_ROOTDIR as _X2GO_SESSIONS_ROOTDIR 
 48   
 49   
50 -class X2goProxyBASE(threading.Thread):
51 """\ 52 X2goProxy is an abstract class for X2Go proxy connections. 53 54 This class needs to be inherited from a concrete proxy class. Only 55 currently available proxy class is: L{X2goProxyNX3}. 56 57 """ 58 PROXY_CMD = '' 59 """Proxy command. Needs to be set by a potential child class, might be OS specific.""" 60 PROXY_ARGS = [] 61 """Arguments to be passed to the proxy command. This needs to be set by a potential child class.""" 62 PROXY_ENV = {} 63 """Provide environment variables to the proxy command. This also needs to be set by a child class.""" 64 65 session_info = None 66 session_log_stdout = None 67 session_log_stderr = None 68 fw_tunnel = None 69 proxy = None 70
71 - def __init__(self, session_info=None, 72 ssh_transport=None, session_log="session.log", 73 sessions_rootdir=os.path.join(_LOCAL_HOME, _X2GO_SESSIONS_ROOTDIR), 74 proxy_options={}, 75 session_instance=None, 76 logger=None, loglevel=log.loglevel_DEFAULT, ):
77 """\ 78 @param session_info: session information provided as an C{X2goServerSessionInfo*} backend 79 instance 80 @type session_info: C{X2goServerSessionInfo*} instance 81 @param ssh_transport: SSH transport object from C{paramiko.SSHClient} 82 @type ssh_transport: C{paramiko.Transport} instance 83 @param session_log: name of the proxy's session logfile 84 @type session_log: C{str} 85 @param sessions_rootdir: base dir where X2Go session files are stored (by default: ~/.x2go) 86 @type sessions_rootdir: C{str} 87 @param proxy_options: a set of very C{X2goProxy*} backend specific options; any option that is not known 88 to the C{X2goProxy*} backend will simply be ignored 89 @type proxy_options: C{dict} 90 @param logger: you can pass an L{X2goLogger} object to the 91 L{X2goProxy} constructor 92 @param session_instance: the L{X2goSession} instance this C{X2goProxy*} instance belongs to 93 @type session_instance: L{X2goSession} instance 94 @type logger: L{X2goLogger} instance 95 @param loglevel: if no L{X2goLogger} object has been supplied a new one will be 96 constructed with the given loglevel 97 @type loglevel: int 98 99 """ 100 if logger is None: 101 self.logger = log.X2goLogger(loglevel=loglevel) 102 else: 103 self.logger = copy.deepcopy(logger) 104 self.logger.tag = __NAME__ 105 106 self.sessions_rootdir = sessions_rootdir 107 self.session_info = session_info 108 self.ssh_transport = ssh_transport 109 self.session_log = session_log 110 self.proxy_options = proxy_options 111 self.session_instance = session_instance 112 self.PROXY_ENV = os.environ.copy() 113 self.proxy = None 114 115 threading.Thread.__init__(self) 116 self.daemon = True
117
118 - def __del__(self):
119 """\ 120 On instance destruction make sure this proxy thread is stopped properly. 121 122 """ 123 self.stop_thread()
124
125 - def _tidy_up(self):
126 """\ 127 Close any left open port forwarding tunnel, also close session log file, 128 if left open. 129 130 """ 131 if self.proxy: 132 self.logger('Shutting down X2Go proxy subprocess', loglevel=log.loglevel_DEBUG) 133 try: 134 self.proxy.kill() 135 except OSError, e: 136 self.logger('X2Go proxy shutdown gave a message that we may ignore: %s' % str(e), loglevel=log.loglevel_WARN) 137 self.proxy = None 138 if self.fw_tunnel is not None: 139 self.logger('Shutting down Paramiko/SSH forwarding tunnel', loglevel=log.loglevel_DEBUG) 140 forward.stop_forward_tunnel(self.fw_tunnel) 141 self.fw_tunnel = None 142 if self.session_log_stdout is not None: 143 self.session_log_stdout.close() 144 if self.session_log_stderr is not None: 145 self.session_log_stderr.close()
146
147 - def stop_thread(self):
148 """\ 149 End the thread runner and tidy up. 150 151 """ 152 self._keepalive = False 153 # wait for thread loop to finish... 154 gevent.sleep(.5) 155 self._tidy_up()
156
157 - def run(self):
158 """\ 159 Start the X2Go proxy command. The X2Go proxy command utilizes a 160 Paramiko/SSH based forwarding tunnel (openssh -L option). This tunnel 161 gets started here and is forked into background (Greenlet/gevent). 162 163 """ 164 self._keepalive = True 165 self.proxy = None 166 167 if self.session_info is None or self.ssh_transport is None: 168 return None 169 170 try: 171 os.makedirs(self.session_info.local_container) 172 except OSError, e: 173 if e.errno == 17: 174 # file exists 175 pass 176 177 local_graphics_port = self.session_info.graphics_port 178 try: 179 if self.ssh_transport.getpeername() in ('::1', '127.0.0.1', 'localhost', 'localhost.localdomain'): 180 local_graphics_port += 10000 181 except socket.error: 182 raise x2go_exceptions.X2goControlSessionException('The control session has died unexpectedly.') 183 local_graphics_port = utils.detect_unused_port(preferred_port=local_graphics_port) 184 185 self.fw_tunnel = forward.start_forward_tunnel(local_port=local_graphics_port, 186 remote_port=self.session_info.graphics_port, 187 ssh_transport=self.ssh_transport, 188 session_instance=self.session_instance, 189 logger=self.logger, 190 ) 191 192 # update the proxy port in PROXY_ARGS 193 self._update_local_proxy_socket(local_graphics_port) 194 cmd_line = self._generate_cmdline() 195 196 self.session_log_stdout = open('%s/%s' % (self.session_info.local_container, self.session_log, ), 'a') 197 self.session_log_stderr = open('%s/%s' % (self.session_info.local_container, self.session_log, ), 'a') 198 self.logger('forking threaded subprocess: %s' % " ".join(cmd_line), loglevel=log.loglevel_DEBUG) 199 200 _stdin = None 201 _shell = False 202 if _X2GOCLIENT_OS == 'Windows': 203 _stdin = file('nul', 'r') 204 _shell = True 205 206 # allow inheriting classes to do something with backend specific proxy_options... 207 self.process_proxy_options() 208 209 while not self.proxy: 210 gevent.sleep(.2) 211 p = self.proxy = subprocess.Popen(cmd_line, 212 env=self.PROXY_ENV, 213 stdin=_stdin, 214 stdout=self.session_log_stdout, 215 stderr=self.session_log_stderr, 216 shell=_shell) 217 218 while self._keepalive: 219 gevent.sleep(.2) 220 221 if _X2GOCLIENT_OS == 'Windows': 222 _stdin.close() 223 try: 224 p.terminate() 225 self.logger('terminating proxy: %s' % p, loglevel=log.loglevel_DEBUG) 226 except OSError, e: 227 if e.errno == 3: 228 # No such process 229 pass 230 except WindowsError: 231 pass
232
233 - def process_proxy_options(self):
234 """\ 235 Override this method to incorporate elements from C{proxy_options} 236 into actual proxy subprocess execution. 237 238 This method (if overridden) should (by design) never fail nor raise an exception. 239 Make sure to catch all possible errors appropriately. 240 241 If you want to log ignored proxy_options then 242 243 1. remove processed proxy_options from self.proxy_options 244 2. once you have finished processing the proxy_options call 245 the parent class method X2goProxyBASE.process_proxy_options() 246 247 """ 248 # do the logging of remaining options 249 if self.proxy_options: 250 self.logger('ignoring non-processed proxy options: %s' % self.proxy_options, loglevel=log.loglevel_INFO)
251
252 - def _update_local_proxy_socket(self, port):
253 pass
254
255 - def _generate_cmdline(self):
256 return ''
257
258 - def start_proxy(self):
259 """\ 260 Start the thread runner and wait for the proxy to come up. 261 262 @return: a subprocess instance that knows about the externally started proxy command. 263 @rtype: C{obj} 264 265 """ 266 threading.Thread.start(self) 267 268 # wait for proxy to get started 269 _count = 0 270 _maxwait = 40 271 while self.proxy is None and _count < _maxwait: 272 _count += 1 273 self.logger('waiting for proxy to come up: 0.4s x %s' % _count, loglevel=log.loglevel_DEBUG) 274 gevent.sleep(.4) 275 276 if self.proxy: 277 278 # also wait for fw_tunnel to become active 279 _count = 0 280 _maxwait = 40 281 while (not self.fw_tunnel.is_active) and (not self.fw_tunnel.failed) and (_count < _maxwait): 282 _count += 1 283 self.logger('waiting for port fw tunnel to come up: 0.5s x %s' % _count, loglevel=log.loglevel_DEBUG) 284 gevent.sleep(.5) 285 286 return self.proxy, bool(self.proxy) and self.fw_tunnel.is_active
287
288 - def ok(self):
289 """\ 290 Check if a proxy instance is up and running. 291 292 @return: Proxy state, C{True} for proxy being up-and-running, C{False} otherwise 293 @rtype C{bool} 294 295 """ 296 return bool(self.proxy and self.proxy.poll() is None) and self.fw_tunnel.is_active
297