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) 2010-2015 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  X2GoProxy 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 X2GoProxy(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{x2go.backends.proxy.nx3.X2GoProxy}.
     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", session_errors="session.err",
     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 L{base.X2GoProxy} backend specific options; any option that is not known
     88              to the L{base.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{base.X2GoProxy} constructor
     92          @param session_instance: the L{X2GoSession} instance this L{base.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.session_errors = session_errors
    112          self.proxy_options = proxy_options
    113          self.session_instance = session_instance
    114          self.PROXY_ENV = os.environ.copy()
    115          self.proxy = None
    116          self.subsystem = 'X2Go Proxy'
    117
    118          threading.Thread.__init__(self)
    119          self.daemon = True
    120
    121 -    def __del__(self):
    122          """\
    123          On instance destruction make sure this proxy thread is stopped properly.
    124
    125          """
    126          self.stop_thread()
    127
    128 -    def _tidy_up(self):
    129          """\
    130          Close any left open port forwarding tunnel, also close session log file,
    131          if left open.
    132
    133          """
    134          if self.proxy:
    135              self.logger('Shutting down X2Go proxy subprocess', loglevel=log.loglevel_DEBUG)
    136              try:
    137                  self.proxy.kill()
    138              except OSError, e:
    139                  self.logger('X2Go proxy shutdown gave a message that we may ignore: %s' % str(e), loglevel=log.loglevel_WARN)
    140              self.proxy = None
    141          if self.fw_tunnel is not None:
    142              self.logger('Shutting down Paramiko/SSH forwarding tunnel', loglevel=log.loglevel_DEBUG)
    143              forward.stop_forward_tunnel(self.fw_tunnel)
    144              self.fw_tunnel = None
    145          if self.session_log_stdout is not None:
    146              self.session_log_stdout.close()
    147          if self.session_log_stderr is not None:
    148              self.session_log_stderr.close()
    149
    150 -    def stop_thread(self):
    151          """\
    152          End the thread runner and tidy up.
    153
    154          """
    155          self._keepalive = False
    156          # wait for thread loop to finish...
    157          while self.proxy is not None:
    158              gevent.sleep(.5)
    159
    160 -    def run(self):
    161          """\
    162          Start the X2Go proxy command. The X2Go proxy command utilizes a
    163          Paramiko/SSH based forwarding tunnel (openssh -L option). This tunnel
    164          gets started here and is forked into background (Greenlet/gevent).
    165
    166          """
    167          self._keepalive = True
    168          self.proxy = None
    169
    170          if self.session_info is None or self.ssh_transport is None:
    171              return None
    172
    173          try:
    174              os.makedirs(self.session_info.local_container)
    175          except OSError, e:
    176              if e.errno == 17:
    177                  # file exists
    178                  pass
    179
    180          local_graphics_port = self.session_info.graphics_port
    181          try:
    182              if self.ssh_transport.getpeername()[0] in ('::1', '127.0.0.1', 'localhost', 'localhost.localdomain'):
    183                  local_graphics_port += 10000
    184          except socket.error:
    185              raise x2go_exceptions.X2GoControlSessionException('The control session has died unexpectedly.')
    186          local_graphics_port = utils.detect_unused_port(preferred_port=local_graphics_port)
    187
    188          self.fw_tunnel = forward.start_forward_tunnel(local_port=local_graphics_port,
    189                                                        remote_port=self.session_info.graphics_port,
    190                                                        ssh_transport=self.ssh_transport,
    191                                                        session_instance=self.session_instance,
    192                                                        session_name=self.session_name,
    193                                                        subsystem=self.subsystem,
    194                                                        logger=self.logger,
    195                                                       )
    196
    197          # update the proxy port in PROXY_ARGS
    198          self._update_local_proxy_socket(local_graphics_port)
    199
    200          self.session_log_stdout = open('%s/%s' % (self.session_info.local_container, self.session_log, ), 'a')
    201          self.session_log_stderr = open('%s/%s' % (self.session_info.local_container, self.session_log, ), 'a')
    202
    203          _stdin = None
    204          _shell = False
    205          if _X2GOCLIENT_OS == 'Windows':
    206              _stdin = file('nul', 'r')
    207              _shell = True
    208
    209          # allow inheriting classes to do something with backend specific proxy_options...
    210          self.process_proxy_options()
    211
    212          # if everything is in place, generate the command line for the subprocess call
    213          cmd_line = self._generate_cmdline()
    214          self.logger('forking threaded subprocess: %s' % " ".join(cmd_line), loglevel=log.loglevel_DEBUG)
    215
    216          while not self.proxy:
    217              gevent.sleep(.2)
    218              p = self.proxy = subprocess.Popen(cmd_line,
    219                                                env=self.PROXY_ENV,
    220                                                stdin=_stdin,
    221                                                stdout=self.session_log_stdout,
    222                                                stderr=self.session_log_stderr,
    223                                                shell=_shell)
    224
    225          while self._keepalive:
    226              gevent.sleep(1)
    227
    228          if _X2GOCLIENT_OS == 'Windows':
    229              _stdin.close()
    230          try:
    231              p.terminate()
    232              self.logger('terminating proxy: %s' % p, loglevel=log.loglevel_DEBUG)
    233          except OSError, e:
    234              if e.errno == 3:
    235                  # No such process
    236                  pass
    237          except WindowsError:
    238              pass
    239
    240          self._tidy_up()
    241
    242 -    def process_proxy_options(self):
    243          """\
    244          Override this method to incorporate elements from C{proxy_options}
    245          into actual proxy subprocess execution.
    246
    247          This method (if overridden) should (by design) never fail nor raise an exception.
    248          Make sure to catch all possible errors appropriately.
    249
    250          If you want to log ignored proxy_options then
    251
    252              1. remove processed proxy_options from self.proxy_options
    253              2. once you have finished processing the proxy_options call
    254              the parent class method L{x2go.backends.proxy.base.X2GoProxy.process_proxy_options()}
    255
    256          """
    257          # do the logging of remaining options
    258          if self.proxy_options:
    259              self.logger('ignoring non-processed proxy options: %s' % self.proxy_options, loglevel=log.loglevel_INFO)
    260
    261 -    def _update_local_proxy_socket(self, port):
    262          pass
    263
    264 -    def _generate_cmdline(self):
    265          return ''
    266
    267 -    def start_proxy(self):
    268          """\
    269          Start the thread runner and wait for the proxy to come up.
    270
    271          @return: a subprocess instance that knows about the externally started proxy command.
    272          @rtype: C{obj}
    273
    274          """
    275          threading.Thread.start(self)
    276
    277          # wait for proxy to get started
    278          _count = 0
    279          _maxwait = 40
    280          while self.proxy is None and _count < _maxwait:
    281              _count += 1
    282              self.logger('waiting for proxy to come up: 0.4s x %s' % _count, loglevel=log.loglevel_DEBUG)
    283              gevent.sleep(.4)
    284
    285          if self.proxy:
    286
    287              # also wait for fw_tunnel to become active
    288              _count = 0
    289              _maxwait = 40
    290              while self.fw_tunnel and (not self.fw_tunnel.is_active) and (not self.fw_tunnel.failed) and (_count < _maxwait):
    291                  _count += 1
    292                  self.logger('waiting for port fw tunnel to come up: 0.5s x %s' % _count, loglevel=log.loglevel_DEBUG)
    293                  gevent.sleep(.5)
    294
    295          return self.proxy, bool(self.proxy) and (self.fw_tunnel and self.fw_tunnel.is_active)
    296
    297 -    def ok(self):
    298          """\
    299          Check if a proxy instance is up and running.
    300
    301          @return: Proxy state, C{True} for proxy being up-and-running, C{False} otherwise
    302          @rtype C{bool}
    303
    304          """
    305          return bool(self.proxy and self.proxy.poll() is None) and self.fw_tunnel.is_active
    306