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OpenStack Study: mech_agent.py**** CubicPower OpenStack Study ****
# Copyright (c) 2013 OpenStack Foundation # 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. from abc import ABCMeta, abstractmethod import six from neutron.extensions import portbindings from neutron.openstack.common import log from neutron.plugins.ml2 import driver_api as api LOG = log.getLogger(__name__) @six.add_metaclass(ABCMeta)
**** CubicPower OpenStack Study **** class AgentMechanismDriverBase(api.MechanismDriver): """Base class for drivers that attach to networks using an L2 agent. The AgentMechanismDriverBase provides common code for mechanism drivers that integrate the ml2 plugin with L2 agents. Port binding with this driver requires the driver's associated agent to be running on the port's host, and that agent to have connectivity to at least one segment of the port's network. MechanismDrivers using this base class must pass the agent type to __init__(), and must implement try_to_bind_segment_for_agent(). """
**** CubicPower OpenStack Study **** def __init__(self, agent_type, supported_vnic_types=[portbindings.VNIC_NORMAL]): """Initialize base class for specific L2 agent type. :param agent_type: Constant identifying agent type in agents_db :param supported_vnic_types: The binding:vnic_type values we can bind """ self.agent_type = agent_type self.supported_vnic_types = supported_vnic_types
**** CubicPower OpenStack Study **** def initialize(self): pass
**** CubicPower OpenStack Study **** def bind_port(self, context): LOG.debug(_("Attempting to bind port %(port)s on " "network %(network)s"), {'port': context.current['id'], 'network': context.network.current['id']}) vnic_type = context.current.get(portbindings.VNIC_TYPE, portbindings.VNIC_NORMAL) if vnic_type not in self.supported_vnic_types: LOG.debug(_("Refusing to bind due to unsupported vnic_type: %s"), vnic_type) return for agent in context.host_agents(self.agent_type): LOG.debug(_("Checking agent: %s"), agent) if agent['alive']: for segment in context.network.network_segments: if self.try_to_bind_segment_for_agent(context, segment, agent): LOG.debug(_("Bound using segment: %s"), segment) return else: LOG.warning(_("Attempting to bind with dead agent: %s"), agent) @abstractmethod
**** CubicPower OpenStack Study **** def try_to_bind_segment_for_agent(self, context, segment, agent): """Try to bind with segment for agent. :param context: PortContext instance describing the port :param segment: segment dictionary describing segment to bind :param agent: agents_db entry describing agent to bind :returns: True iff segment has been bound for agent Called inside transaction during bind_port() so that derived MechanismDrivers can use agent_db data along with built-in knowledge of the corresponding agent's capabilities to attempt to bind to the specified network segment for the agent. If the segment can be bound for the agent, this function must call context.set_binding() with appropriate values and then return True. Otherwise, it must return False. """ @six.add_metaclass(ABCMeta)
**** CubicPower OpenStack Study **** class SimpleAgentMechanismDriverBase(AgentMechanismDriverBase): """Base class for simple drivers using an L2 agent. The SimpleAgentMechanismDriverBase provides common code for mechanism drivers that integrate the ml2 plugin with L2 agents, where the binding:vif_type and binding:vif_details values are the same for all bindings. Port binding with this driver requires the driver's associated agent to be running on the port's host, and that agent to have connectivity to at least one segment of the port's network. MechanismDrivers using this base class must pass the agent type and the values for binding:vif_type and binding:vif_details to __init__(), and must implement check_segment_for_agent(). """
**** CubicPower OpenStack Study **** def __init__(self, agent_type, vif_type, vif_details, supported_vnic_types=[portbindings.VNIC_NORMAL]): """Initialize base class for specific L2 agent type. :param agent_type: Constant identifying agent type in agents_db :param vif_type: Value for binding:vif_type when bound :param vif_details: Dictionary with details for VIF driver when bound :param supported_vnic_types: The binding:vnic_type values we can bind """ super(SimpleAgentMechanismDriverBase, self).__init__( agent_type, supported_vnic_types) self.vif_type = vif_type self.vif_details = vif_details
**** CubicPower OpenStack Study **** def try_to_bind_segment_for_agent(self, context, segment, agent): if self.check_segment_for_agent(segment, agent): context.set_binding(segment[api.ID], self.vif_type, self.vif_details) return True else: return False @abstractmethod
**** CubicPower OpenStack Study **** def check_segment_for_agent(self, segment, agent): """Check if segment can be bound for agent. :param segment: segment dictionary describing segment to bind :param agent: agents_db entry describing agent to bind :returns: True iff segment can be bound for agent Called inside transaction during bind_port so that derived MechanismDrivers can use agent_db data along with built-in knowledge of the corresponding agent's capabilities to determine whether or not the specified network segment can be bound for the agent. """
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