ncclient:NETCONF Python client

# Copyright 2009 Shikhar Bhushan

#

# 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 logging

from threading import Thread, Event

from Queue import Queue

import content

from capabilities import CAPABILITIES

from error import ClientError

from subject import Subject

logger = logging.getLogger('ncclient.session')

class SessionError(ClientError): pass

class Session(Thread, Subject):

    def __init__(self):

        Thread.__init__(self, name='session')

        Subject.__init__(self, listeners=[Session.HelloListener(self)])

        self._client_capabilities = CAPABILITIES

        self._server_capabilities = None # yet

        self._id = None # session-id

        self._error = None

        self._init_event = Event()

        self._q = Queue()

        self._connected = False # to be set/cleared by subclass

    def _post_connect(self):

        # start the subclass' main loop

        self.start()

        # queue client's hello message for sending

        self.send(content.make_hello(self._client_capabilities))

        # we expect server's hello message, wait for _init_event to be set by HelloListener

        self._init_event.wait()

        # there may have been an error

        if self._error:

            self._close()

            raise self._error

    def send(self, message):

        message = (u'<?xml version="1.0" encoding="UTF-8"?>%s' %

                   message).encode('utf-8')

        logger.debug('queueing message: \n%s' % message)

        self._q.put(message)

    def connect(self):

        raise NotImplementedError

    def run(self):

        raise NotImplementedError

    ### Properties

    @property

    def client_capabilities(self):

        return self._client_capabilities

    @property

    def server_capabilities(self):

        return self._server_capabilities

    @property

    def connected(self):

        return self._connected

    @property

    def id(self):

        return self._id

    class HelloListener:

        def __str__(self):

            return 'HelloListener'

        def __init__(self, session):

            self._session = session

        def _done(self, err=None):

            if err is not None:

                self._session._error = err

            self._session.remove_listener(self)

            self._session._init_event.set()

        def reply(self, data):

            err = None

            try:

                id, capabilities = content.parse_hello(data)

                logger.debug('session_id: %s | capabilities: \n%s', id, capabilities)

                self._session._id, self._session.capabilities = id, capabilities

            except Exception as e:

                err = e

            finally:

                self._done(err)

        def error(self, err):

            self._done(err)