@@ -34,21 +34,19 @@ class AgentMechanismDriverBase(api.MechanismDriver):
3434 running on the port's host, and that agent to have connectivity to
3535 at least one segment of the port's network.
3636
37- MechanismDrivers using this base class must pass the agent type
38- and VIF type constants to __init__(), and must implement
37+ MechanismDrivers using this base class must pass the agent type to
38+ __init__(), and must implement try_to_bind_segment_for_agent() and
3939 check_segment_for_agent().
4040 """
4141
42- def __init__ (self , agent_type , vif_type , cap_port_filter ,
42+ def __init__ (self , agent_type ,
4343 supported_vnic_types = [portbindings .VNIC_NORMAL ]):
4444 """Initialize base class for specific L2 agent type.
4545
4646 :param agent_type: Constant identifying agent type in agents_db
47- :param vif_type: Value for binding:vif_type to when bound
47+ :param supported_vnic_types: The binding:vnic_type values we can bind
4848 """
4949 self .agent_type = agent_type
50- self .vif_type = vif_type
51- self .cap_port_filter = cap_port_filter
5250 self .supported_vnic_types = supported_vnic_types
5351
5452 def initialize (self ):
@@ -69,10 +67,8 @@ def bind_port(self, context):
6967 LOG .debug (_ ("Checking agent: %s" ), agent )
7068 if agent ['alive' ]:
7169 for segment in context .network .network_segments :
72- if self .check_segment_for_agent (segment , agent ):
73- context .set_binding (segment [api .ID ],
74- self .vif_type ,
75- self .cap_port_filter )
70+ if self .try_to_bind_segment_for_agent (context , segment ,
71+ agent ):
7672 LOG .debug (_ ("Bound using segment: %s" ), segment )
7773 return
7874 else :
@@ -99,6 +95,25 @@ def unbind_port(self, context):
9995 {'port' : context .current ['id' ],
10096 'network' : context .network .current ['id' ]})
10197
98+ @abstractmethod
99+ def try_to_bind_segment_for_agent (self , context , segment , agent ):
100+ """Try to bind with segment for agent.
101+
102+ :param context: PortContext instance describing the port
103+ :param segment: segment dictionary describing segment to bind
104+ :param agent: agents_db entry describing agent to bind
105+ :returns: True iff segment has been bound for agent
106+
107+ Called inside transaction during bind_port() so that derived
108+ MechanismDrivers can use agent_db data along with built-in
109+ knowledge of the corresponding agent's capabilities to attempt
110+ to bind to the specified network segment for the agent.
111+
112+ If the segment can be bound for the agent, this function must
113+ call context.set_binding() with appropriate values and then
114+ return True. Otherwise, it must return False.
115+ """
116+
102117 @abstractmethod
103118 def check_segment_for_agent (self , segment , agent ):
104119 """Check if segment can be bound for agent.
@@ -107,9 +122,49 @@ def check_segment_for_agent(self, segment, agent):
107122 :param agent: agents_db entry describing agent to bind
108123 :returns: True iff segment can be bound for agent
109124
110- Called inside transaction during bind_port () and
111- validate_port_binding() so that derived MechanismDrivers can
112- use agent_db data along with built-in knowledge of the
113- corresponding agent's capabilities to determine whether or not
114- the specified network segment can be bound for the agent.
125+ Called inside transaction during validate_port_binding () so
126+ that derived MechanismDrivers can use agent_db data along with
127+ built-in knowledge of the corresponding agent's capabilities
128+ to determine whether or not the specified network segment can
129+ be bound for the agent.
115130 """
131+
132+
133+ @six .add_metaclass (ABCMeta )
134+ class SimpleAgentMechanismDriverBase (AgentMechanismDriverBase ):
135+ """Base class for simple drivers using an L2 agent.
136+
137+ The SimpleAgentMechanismDriverBase provides common code for
138+ mechanism drivers that integrate the ml2 plugin with L2 agents,
139+ where the binding:vif_type and binding:vif_details values are the
140+ same for all bindings. Port binding with this driver requires the
141+ driver's associated agent to be running on the port's host, and
142+ that agent to have connectivity to at least one segment of the
143+ port's network.
144+
145+ MechanismDrivers using this base class must pass the agent type
146+ and the values for binding:vif_type and binding:vif_details to
147+ __init__(). They must implement check_segment_for_agent() as
148+ defined in AgentMechanismDriverBase, which will be called during
149+ both binding establishment and validation.
150+ """
151+
152+ def __init__ (self , agent_type , vif_type , vif_details ,
153+ supported_vnic_types = [portbindings .VNIC_NORMAL ]):
154+ """Initialize base class for specific L2 agent type.
155+
156+ :param agent_type: Constant identifying agent type in agents_db
157+ :param vif_type: Value for binding:vif_type when bound
158+ :param vif_details: Dictionary with details for VIF driver when bound
159+ :param supported_vnic_types: The binding:vnic_type values we can bind
160+ """
161+ super (SimpleAgentMechanismDriverBase , self ).__init__ (
162+ agent_type , supported_vnic_types )
163+ self .vif_type = vif_type
164+ self .vif_details = vif_details
165+
166+ def try_to_bind_segment_for_agent (self , context , segment , agent ):
167+ if self .check_segment_for_agent (segment , agent ):
168+ context .set_binding (segment [api .ID ],
169+ self .vif_type ,
170+ self .vif_details )
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