text: # Copyright (c) 2013 Hortonworks, Inc.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #    http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  # implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  import os
  import shlex
  
  from eventlet.green import subprocess as e_subprocess
  from neutronclient.neutron import client as neutron_cli
  import requests
  from requests import adapters
  
  from sahara import context
  from sahara import exceptions as ex
  from sahara.openstack.common import log as logging
  from sahara.utils.openstack import base
  
  
  LOG = logging.getLogger(__name__)
  
  
  def client():
      ctx = context.ctx()
      args = {
          'username': ctx.username,
          'tenant_name': ctx.tenant_name,
          'tenant_id': ctx.tenant_id,
          'token': ctx.token,
          'endpoint_url': base.url_for(ctx.service_catalog, 'network')
      }
      return neutron_cli.Client('2.0', **args)
  
  
  class NeutronClientRemoteWrapper():
      neutron = None
      adapters = {}
      routers = {}
  
      def __init__(self, network, uri, token, tenant_name):
          self.neutron = neutron_cli.Client('2.0',
                                            endpoint_url=uri,
                                            token=token,
                                            tenant_name=tenant_name)
          self.network = network
  
      def get_router(self):
          matching_router = NeutronClientRemoteWrapper.routers.get(self.network,
                                                                   None)
          if matching_router:
              LOG.debug('Returning cached qrouter')
              return matching_router['id']
  
          routers = self.neutron.list_routers()['routers']
          for router in routers:
              device_id = router['id']
              ports = self.neutron.list_ports(device_id=device_id)['ports']
              port = next((port for port in ports
                           if port['network_id'] == self.network), None)
              if port:
                  matching_router = router
                  NeutronClientRemoteWrapper.routers[
                      self.network] = matching_router
                  break
  
          if not matching_router:
              raise ex.SystemError('Neutron router corresponding to network {0} '
                                   'is not found'.format(self.network))
  
          return matching_router['id']
  
      def get_http_session(self, host, port=None, *args, **kwargs):
          session = requests.Session()
          adapters = self._get_adapters(host, port=port, *args, **kwargs)
          for adapter in adapters:
              session.mount('http://{0}:{1}'.format(host, adapter.port), adapter)
  
          return session
  
      def _get_adapters(self, host, port=None, *args, **kwargs):
          LOG.debug('Retrieving neutron adapters for {0}:{1}'.format(host, port))
          adapters = []
          if not port:
              # returning all registered adapters for given host
              adapters = [adapter for adapter in self.adapters
                          if adapter.host == host]
          else:
              # need to retrieve or create specific adapter
              adapter = self.adapters.get((host, port), None, *args, **kwargs)
              if not adapter:
                  LOG.debug('Creating neutron adapter for {0}:{1}'
                            .format(host, port))
                  qrouter = self.get_router()
                  adapter = (
                      NeutronHttpAdapter(qrouter, host, port))
                  self.adapters[(host, port)] = adapter
                  adapters = [adapter]
  
          return adapters
  
  
  class NeutronHttpAdapter(adapters.HTTPAdapter):
      port = None
      host = None
  
      def __init__(self, qrouter, host, port, *args, **kwargs):
          super(NeutronHttpAdapter, self).__init__(*args, **kwargs)
          command = 'ip netns exec qrouter-{0} nc {1} {2}'.format(qrouter,
                                                                  host, port)
          LOG.debug('Neutron adapter created with cmd {0}'.format(command))
          self.cmd = shlex.split(command)
          self.port = port
          self.host = host
  
      def get_connection(self, url, proxies=None):
          pool_conn = (
              super(NeutronHttpAdapter, self).get_connection(url, proxies))
          if hasattr(pool_conn, '_get_conn'):
              http_conn = pool_conn._get_conn()
              if http_conn.sock is None:
                  if hasattr(http_conn, 'connect'):
                      sock = self._connect()
                      LOG.debug('HTTP connecction {0} getting new '
                                'netcat socket {1}'.format(http_conn, sock))
                      http_conn.sock = sock
              else:
                  if hasattr(http_conn.sock, 'is_netcat_socket'):
                      LOG.debug('pooled http connection has existing '
                                'netcat socket. resetting pipe...')
                      http_conn.sock.reset()
  
              pool_conn._put_conn(http_conn)
  
          return pool_conn
  
      def close(self):
          LOG.debug('Closing neutron adapter for {0}:{1}'
                    .format(self.host, self.port))
          super(NeutronHttpAdapter, self).close()
  
      def _connect(self):
          LOG.debug('returning netcat socket with command {0}'
                    .format(self.cmd))
          return NetcatSocket(self.cmd)
  
  
  class NetcatSocket:
  
      def _create_process(self):
          self.process = e_subprocess.Popen(self.cmd,
                                            stdin=e_subprocess.PIPE,
                                            stdout=e_subprocess.PIPE,
                                            stderr=e_subprocess.PIPE)
  
      def __init__(self, cmd):
          self.cmd = cmd
          self._create_process()
  
      def send(self, content):
          try:
              self.process.stdin.write(content)
          except IOError as e:
              raise ex.SystemError(e)
          return len(content)
  
      def sendall(self, content):
          return self.send(content)
  
      def makefile(self, mode, *arg):
          if mode.startswith('r'):
              return self.process.stdout
          if mode.startswith('w'):
              return self.process.stdin
          raise ex.IncorrectStateError("Unknown file mode %s" % mode)
  
      def recv(self, size):
          try:
              return os.read(self.process.stdout.fileno(), size)
          except IOError as e:
              raise ex.SystemError(e)
  
      def _terminate(self):
          self.process.terminate()
  
      def close(self):
          LOG.debug('Socket close called')
          self._terminate()
  
      def settimeout(self, timeout):
          pass
  
      def fileno(self):
          return self.process.stdin.fileno()
  
      def is_netcat_socket(self):
          return True
  
      def reset(self):
          self._terminate()
          self._create_process()
  