1# Copyright (C) 2017 Nippon Telegraph and Telephone Corporation.
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#    http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
12# implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15
16"""
17Events for Zebra protocol service.
18"""
19
20import inspect
21import logging
22
23from ryu import utils
24from ryu.controller import event
25from ryu.lib.packet import zebra
26
27
28LOG = logging.getLogger(__name__)
29MOD = utils.import_module(__name__)
30
31ZEBRA_EVENTS = []
32
33
34class EventZebraBase(event.EventBase):
35    """
36    The base class for Zebra protocol service event class.
37
38    The subclasses have at least ``zclient`` and the same attributes with
39    :py:class: `ryu.lib.packet.zebra.ZebraMessage`.
40    ``zclient`` is an instance of Zebra client class. See
41    :py:class: `ryu.services.protocols.zebra.client.zclient.ZClient` or
42    :py:class: `ryu.services.protocols.zebra.server.zserver.ZClient`.
43
44    The subclasses are named as::
45
46        ``"Event" + <Zebra message body class name>``
47
48    For Example, if the service received ZEBRA_INTERFACE_ADD message,
49    the body class should be
50    :py:class: `ryu.lib.packet.zebra.ZebraInterfaceAdd`, then the event
51    class will be named as::
52
53        "Event" + "ZebraInterfaceAdd" = "EventZebraInterfaceAdd"
54
55    ``msg`` argument must be an instance of
56    :py:class: `ryu.lib.packet.zebra.ZebraMessage` and used to extract the
57    attributes for the event classes.
58    """
59
60    def __init__(self, zclient, msg):
61        super(EventZebraBase, self).__init__()
62        assert isinstance(msg, zebra.ZebraMessage)
63        self.__dict__ = msg.__dict__
64        self.zclient = zclient
65
66    def __repr__(self):
67        m = ', '.join(
68            ['%s=%r' % (k, v)
69             for k, v in self.__dict__.items() if not k.startswith('_')])
70        return "%s(%s)" % (self.__class__.__name__, m)
71
72    __str__ = __repr__
73
74
75def _event_name(body_cls):
76    return 'Event%s' % body_cls.__name__
77
78
79def message_to_event(zclient, msg):
80    """
81    Converts Zebra protocol message instance to Zebra protocol service
82    event instance.
83
84    If corresponding event class is not defined, returns None.
85
86    :param zclient: Zebra client instance.
87    :param msg: Zebra protocol message.
88    :return: Zebra protocol service event.
89    """
90    if not isinstance(msg, zebra.ZebraMessage):
91        return None
92
93    body_cls = msg.get_body_class(msg.version, msg.command)
94    ev_cls = getattr(MOD, _event_name(body_cls), None)
95    if ev_cls is None:
96        return None
97
98    return ev_cls(zclient, msg)
99
100
101def _define_event_class(body_cls):
102    name = _event_name(body_cls)
103
104    event_cls = type(name, (EventZebraBase,), {})
105    globals()[name] = event_cls
106
107    return event_cls
108
109
110def _generate_event_classes():
111    for zebra_cls in zebra.__dict__.values():
112        if (not inspect.isclass(zebra_cls)
113                or not issubclass(zebra_cls, zebra._ZebraMessageBody)
114                or zebra_cls.__name__.startswith('_')):
115            continue
116
117        ev = _define_event_class(zebra_cls)
118        # LOG.debug('Generated Zebra event: %s' % ev)
119        ZEBRA_EVENTS.append(ev)
120
121
122_generate_event_classes()
123