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.

from threading import Lock

from weakref import WeakValueDictionary

import logging

logger = logging.getLogger('ncclient.rpc.listener')

class RPCReplyListener(Listener):

    # one instance per session

    def __new__(cls, session):

        instance = session.get_listener_instance(cls)

        if instance is None:

            instance = object.__new__(cls)

            instance._lock = Lock()

            instance._id2rpc = WeakValueDictionary()

            instance._pipelined = session.can_pipeline

            instance._errback = None

            session.add_listener(instance)

        return instance

    def register(self, id, rpc):

        with self._lock:

            self._id2rpc[id] = rpc

    def callback(self, root, raw):

        tag, attrs = root

        if __(tag) != 'rpc-reply':

            return

        rpc = None

        for key in attrs:

            if __(key) == 'message-id':

                id = attrs[key]

                try:

                    with self._lock:

                        rpc = self._id2rpc.pop(id)

                except KeyError:

                    logger.warning('no object registered for message-id: [%s]' % id)

                except Exception as e:

                    logger.debug('error - %r' % e)

                break

        else:

            if not self._pipelined:

                with self._lock:

                    assert(len(self._id2rpc) == 1)

                    rpc = self._id2rpc.values()[0]

                    self._id2rpc.clear()

            else:

                logger.warning('<rpc-reply> without message-id received: %s' % raw)

        logger.debug('delivering to %r' % rpc)

        rpc.deliver(raw)

    def set_errback(self, errback):

        self._errback = errback

    def errback(self, err):

        if self._errback is not None:

            self._errback(err)