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) 2010-2013 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  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.session_name = self.session_info.name
    109          self.ssh_transport = ssh_transport
    110          self.session_log = session_log
    111          self.proxy_options = proxy_options
    112          self.session_instance = session_instance
    113          self.PROXY_ENV = os.environ.copy()
    114          self.proxy = None
    115
    116          threading.Thread.__init__(self)
    117          self.daemon = True
    118
    119 -    def __del__(self):
    120          """\
    121          On instance destruction make sure this proxy thread is stopped properly.
    122
    123          """
    124          self.stop_thread()
    125
    126 -    def _tidy_up(self):
    127          """\
    128          Close any left open port forwarding tunnel, also close session log file,
    129          if left open.
    130
    131          """
    132          if self.proxy:
    133              self.logger('Shutting down X2Go proxy subprocess', loglevel=log.loglevel_DEBUG)
    134              try:
    135                  self.proxy.kill()
    136              except OSError, e:
    137                  self.logger('X2Go proxy shutdown gave a message that we may ignore: %s' % str(e), loglevel=log.loglevel_WARN)
    138              self.proxy = None
    139          if self.fw_tunnel is not None:
    140              self.logger('Shutting down Paramiko/SSH forwarding tunnel', loglevel=log.loglevel_DEBUG)
    141              forward.stop_forward_tunnel(self.fw_tunnel)
    142              self.fw_tunnel = None
    143          if self.session_log_stdout is not None:
    144              self.session_log_stdout.close()
    145          if self.session_log_stderr is not None:
    146              self.session_log_stderr.close()
    147
    148 -    def stop_thread(self):
    149          """\
    150          End the thread runner and tidy up.
    151
    152          """
    153          self._keepalive = False
    154          # wait for thread loop to finish...
    155          gevent.sleep(.5)
    156          self._tidy_up()
    157
    158 -    def run(self):
    159          """\
    160          Start the X2Go proxy command. The X2Go proxy command utilizes a
    161          Paramiko/SSH based forwarding tunnel (openssh -L option). This tunnel
    162          gets started here and is forked into background (Greenlet/gevent).
    163
    164          """
    165          self._keepalive = True
    166          self.proxy = None
    167
    168          if self.session_info is None or self.ssh_transport is None:
    169              return None
    170
    171          try:
    172              os.makedirs(self.session_info.local_container)
    173          except OSError, e:
    174              if e.errno == 17:
    175                  # file exists
    176                  pass
    177
    178          local_graphics_port = self.session_info.graphics_port
    179          try:
    180              if self.ssh_transport.getpeername() in ('::1', '127.0.0.1', 'localhost', 'localhost.localdomain'):
    181                  local_graphics_port += 10000
    182          except socket.error:
    183              raise x2go_exceptions.X2GoControlSessionException('The control session has died unexpectedly.')
    184          local_graphics_port = utils.detect_unused_port(preferred_port=local_graphics_port)
    185
    186          self.fw_tunnel = forward.start_forward_tunnel(local_port=local_graphics_port,
    187                                                        remote_port=self.session_info.graphics_port,
    188                                                        ssh_transport=self.ssh_transport,
    189                                                        session_instance=self.session_instance,
    190                                                        session_name=self.session_name,
    191                                                        logger=self.logger,
    192                                                       )
    193
    194          # update the proxy port in PROXY_ARGS
    195          self._update_local_proxy_socket(local_graphics_port)
    196          cmd_line = self._generate_cmdline()
    197
    198          self.session_log_stdout = open('%s/%s' % (self.session_info.local_container, self.session_log, ), 'a')
    199          self.session_log_stderr = open('%s/%s' % (self.session_info.local_container, self.session_log, ), 'a')
    200          self.logger('forking threaded subprocess: %s' % " ".join(cmd_line), loglevel=log.loglevel_DEBUG)
    201
    202          _stdin = None
    203          _shell = False
    204          if _X2GOCLIENT_OS == 'Windows':
    205              _stdin = file('nul', 'r')
    206              _shell = True
    207
    208          # allow inheriting classes to do something with backend specific proxy_options...
    209          self.process_proxy_options()
    210
    211          while not self.proxy:
    212              gevent.sleep(.2)
    213              p = self.proxy = subprocess.Popen(cmd_line,
    214                                                env=self.PROXY_ENV,
    215                                                stdin=_stdin,
    216                                                stdout=self.session_log_stdout,
    217                                                stderr=self.session_log_stderr,
    218                                                shell=_shell)
    219
    220          while self._keepalive:
    221              gevent.sleep(.2)
    222
    223          if _X2GOCLIENT_OS == 'Windows':
    224              _stdin.close()
    225          try:
    226              p.terminate()
    227              self.logger('terminating proxy: %s' % p, loglevel=log.loglevel_DEBUG)
    228          except OSError, e:
    229              if e.errno == 3:
    230                  # No such process
    231                  pass
    232          except WindowsError:
    233              pass
    234
    235 -    def process_proxy_options(self):
    236          """\
    237          Override this method to incorporate elements from C{proxy_options}
    238          into actual proxy subprocess execution.
    239
    240          This method (if overridden) should (by design) never fail nor raise an exception.
    241          Make sure to catch all possible errors appropriately.
    242
    243          If you want to log ignored proxy_options then
    244
    245              1. remove processed proxy_options from self.proxy_options
    246              2. once you have finished processing the proxy_options call
    247              the parent class method X2GoProxyBASE.process_proxy_options()
    248
    249          """
    250          # do the logging of remaining options
    251          if self.proxy_options:
    252              self.logger('ignoring non-processed proxy options: %s' % self.proxy_options, loglevel=log.loglevel_INFO)
    253
    254 -    def _update_local_proxy_socket(self, port):
    255          pass
    256
    257 -    def _generate_cmdline(self):
    258          return ''
    259
    260 -    def start_proxy(self):
    261          """\
    262          Start the thread runner and wait for the proxy to come up.
    263
    264          @return: a subprocess instance that knows about the externally started proxy command.
    265          @rtype: C{obj}
    266
    267          """
    268          threading.Thread.start(self)
    269
    270          # wait for proxy to get started
    271          _count = 0
    272          _maxwait = 40
    273          while self.proxy is None and _count < _maxwait:
    274              _count += 1
    275              self.logger('waiting for proxy to come up: 0.4s x %s' % _count, loglevel=log.loglevel_DEBUG)
    276              gevent.sleep(.4)
    277
    278          if self.proxy:
    279
    280              # also wait for fw_tunnel to become active
    281              _count = 0
    282              _maxwait = 40
    283              while (not self.fw_tunnel.is_active) and (not self.fw_tunnel.failed) and (_count < _maxwait):
    284                  _count += 1
    285                  self.logger('waiting for port fw tunnel to come up: 0.5s x %s' % _count, loglevel=log.loglevel_DEBUG)
    286                  gevent.sleep(.5)
    287
    288          return self.proxy, bool(self.proxy) and self.fw_tunnel.is_active
    289
    290 -    def ok(self):
    291          """\
    292          Check if a proxy instance is up and running.
    293
    294          @return: Proxy state, C{True} for proxy being up-and-running, C{False} otherwise
    295          @rtype C{bool}
    296
    297          """
    298          return bool(self.proxy and self.proxy.poll() is None) and self.fw_tunnel.is_active
    299