OpenStack Study: l3_gwmode_db.py

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# Copyright 2013 VMware, Inc. All rights reserved.

#

# 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 sqlalchemy as sa

from neutron.db import db_base_plugin_v2

from neutron.db import l3_db

from neutron.extensions import l3

from neutron.openstack.common import log as logging

LOG = logging.getLogger(__name__)

EXTERNAL_GW_INFO = l3.EXTERNAL_GW_INFO

# Modify the Router Data Model adding the enable_snat attribute

setattr(l3_db.Router, 'enable_snat',

sa.Column(sa.Boolean, default=True, nullable=False))

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class L3_NAT_db_mixin(l3_db.L3_NAT_db_mixin):

"""Mixin class to add configurable gateway modes."""

# Register dict extend functions for ports and networks

db_base_plugin_v2.NeutronDbPluginV2.register_dict_extend_funcs(

l3.ROUTERS, ['_extend_router_dict_gw_mode'])

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    def _extend_router_dict_gw_mode(self, router_res, router_db):

        if router_db.gw_port_id:

            nw_id = router_db.gw_port['network_id']

            router_res[EXTERNAL_GW_INFO] = {

                'network_id': nw_id,

                'enable_snat': router_db.enable_snat}

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    def _update_router_gw_info(self, context, router_id, info, router=None):

        # Load the router only if necessary

        if not router:

            router = self._get_router(context, router_id)

        # if enable_snat is not specified use the value

        # stored in the database (default:True)

        enable_snat = not info or info.get('enable_snat', router.enable_snat)

        with context.session.begin(subtransactions=True):

            router.enable_snat = enable_snat

        # Calls superclass, pass router db object for avoiding re-loading

        super(L3_NAT_db_mixin, self)._update_router_gw_info(

            context, router_id, info, router=router)

        # Returning the router might come back useful if this

        # method is overriden in child classes

        return router

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    def _build_routers_list(self, routers, gw_ports):

        gw_port_id_gw_port_dict = {}

        for gw_port in gw_ports:

            gw_port_id_gw_port_dict[gw_port['id']] = gw_port

        for rtr in routers:

            gw_port_id = rtr['gw_port_id']

            if gw_port_id:

                rtr['gw_port'] = gw_port_id_gw_port_dict[gw_port_id]

                # Add enable_snat key

                rtr['enable_snat'] = rtr[EXTERNAL_GW_INFO]['enable_snat']

        return routers