Get rid of delete_subnet method in ML2
This method has grown to be one of the most hideous methods in Neutron. It's well past Icehouse so it's time to address the REVISIT and get rid of it entirely. :) This patch refactors ML2 and the db_base_plugin_v2 delete_subnet method so ML2 can perform its ML2-specific tasks with callbacks and db_base_plugin_v2 can handle the rest. Partial-Bug: #1666424 Change-Id: Ie29acfbe323b60205ade9d660f7497f5bf4a35ca
This commit is contained in:
Kevin Benton
parent
1f5ee0e894
commit
31fa23d84c
@ -26,6 +26,7 @@ from oslo_log import log as logging
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from oslo_utils import excutils
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from oslo_utils import uuidutils
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from sqlalchemy import and_
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from sqlalchemy import exc as sql_exc
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from sqlalchemy import not_
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from neutron._i18n import _, _LE, _LI
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@ -883,10 +884,6 @@ class NeutronDbPluginV2(db_base_plugin_common.DbBasePluginCommon,
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return result
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def _subnet_check_ip_allocations(self, context, subnet_id):
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return (context.session.query(models_v2.IPAllocation).
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filter_by(subnet_id=subnet_id).join(models_v2.Port).first())
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def _subnet_get_user_allocation(self, context, subnet_id):
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"""Check if there are any user ports on subnet and return first."""
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# need to join with ports table as IPAllocation's port
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@ -912,41 +909,24 @@ class NeutronDbPluginV2(db_base_plugin_common.DbBasePluginCommon,
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raise exc.SubnetInUse(subnet_id=subnet_id)
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@db_api.retry_if_session_inactive()
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def delete_subnet(self, context, id):
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with context.session.begin(subtransactions=True):
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subnet = self._get_subnet(context, id)
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def _remove_subnet_from_port(self, context, sub_id, port_id, auto_subnet):
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try:
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fixed = [f for f in self.get_port(context, port_id)['fixed_ips']
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if f['subnet_id'] != sub_id]
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if auto_subnet:
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# special flag to avoid re-allocation on auto subnets
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fixed.append({'subnet_id': sub_id, 'delete_subnet': True})
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data = {attributes.PORT: {'fixed_ips': fixed}}
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self.update_port(context, port_id, data)
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except exc.PortNotFound:
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# port is gone
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return
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except exc.SubnetNotFound as e:
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# another subnet in the fixed ips was concurrently removed. retry
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raise os_db_exc.RetryRequest(e)
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# Make sure the subnet isn't used by other resources
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_check_subnet_not_used(context, id)
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# Delete all network owned ports
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qry_network_ports = (
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context.session.query(models_v2.IPAllocation).
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filter_by(subnet_id=subnet['id']).
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join(models_v2.Port))
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# Remove network owned ports, and delete IP allocations
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# for IPv6 addresses which were automatically generated
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# via SLAAC
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is_auto_addr_subnet = ipv6_utils.is_auto_address_subnet(subnet)
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if is_auto_addr_subnet:
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self._subnet_check_ip_allocations_internal_router_ports(
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context, id)
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else:
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qry_network_ports = (
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qry_network_ports.filter(models_v2.Port.device_owner.
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in_(AUTO_DELETE_PORT_OWNERS)))
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network_ports = qry_network_ports.all()
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if network_ports:
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for port in network_ports:
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context.session.delete(port)
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# Check if there are more IP allocations, unless
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# is_auto_address_subnet is True. In that case the check is
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# unnecessary. This additional check not only would be wasteful
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# for this class of subnet, but is also error-prone since when
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# the isolation level is set to READ COMMITTED allocations made
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# concurrently will be returned by this query
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if not is_auto_addr_subnet:
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alloc = self._subnet_check_ip_allocations(context, id)
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def _ensure_no_user_ports_on_subnet(self, context, id):
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alloc = self._subnet_get_user_allocation(context, id)
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if alloc:
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LOG.info(_LI("Found port (%(port_id)s, %(ip)s) having IP "
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"allocation on subnet "
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@ -956,10 +936,43 @@ class NeutronDbPluginV2(db_base_plugin_common.DbBasePluginCommon,
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'subnet': id})
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raise exc.SubnetInUse(subnet_id=id)
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context.session.delete(subnet)
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@db_api.retry_if_session_inactive()
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def _remove_subnet_ip_allocations_from_ports(self, context, id):
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# Do not allow a subnet to be deleted if a router is attached to it
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self._subnet_check_ip_allocations_internal_router_ports(
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context, id)
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subnet = self._get_subnet(context, id)
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is_auto_addr_subnet = ipv6_utils.is_auto_address_subnet(subnet)
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if not is_auto_addr_subnet:
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# we only automatically remove IP addresses from user ports if
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# the IPs come from auto allocation subnets.
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self._ensure_no_user_ports_on_subnet(context, id)
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net_allocs = (context.session.query(models_v2.IPAllocation.port_id).
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filter_by(subnet_id=id))
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port_ids_on_net = [ipal.port_id for ipal in net_allocs]
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for port_id in port_ids_on_net:
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self._remove_subnet_from_port(context, id, port_id,
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auto_subnet=is_auto_addr_subnet)
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@db_api.retry_if_session_inactive()
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def delete_subnet(self, context, id):
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LOG.debug("Deleting subnet %s", id)
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# Make sure the subnet isn't used by other resources
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_check_subnet_not_used(context, id)
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self._remove_subnet_ip_allocations_from_ports(context, id)
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# retry integrity errors to catch ip allocation races
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with db_api.exc_to_retry(sql_exc.IntegrityError), \
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context.session.begin(subtransactions=True):
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subnet_db = self._get_subnet(context, id)
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subnet = self._make_subnet_dict(subnet_db, context=context)
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registry.notify(resources.SUBNET, events.PRECOMMIT_DELETE,
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self, context=context, subnet_id=id)
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context.session.delete(subnet_db)
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# Delete related ipam subnet manually,
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# since there is no FK relationship
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self.ipam.delete_subnet(context, id)
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registry.notify(resources.SUBNET, events.AFTER_DELETE,
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self, context=context, subnet=subnet)
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@db_api.retry_if_session_inactive()
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def get_subnet(self, context, id, fields=None):
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@ -43,7 +43,6 @@ from neutron.callbacks import exceptions
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from neutron.callbacks import registry
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from neutron.callbacks import resources
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from neutron.common import constants as n_const
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from neutron.common import ipv6_utils
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from neutron.common import rpc as n_rpc
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from neutron.common import topics
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from neutron.common import utils
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@ -964,142 +963,30 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
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return updated_subnet
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@utils.transaction_guard
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@db_api.retry_if_session_inactive()
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def delete_subnet(self, context, id):
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# REVISIT(rkukura) The super(Ml2Plugin, self).delete_subnet()
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# function is not used because it deallocates the subnet's addresses
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# from ports in the DB without invoking the derived class's
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# update_port(), preventing mechanism drivers from being called.
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# This approach should be revisited when the API layer is reworked
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# during icehouse.
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# the only purpose of this override is to protect this from being
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# called inside of a transaction.
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return super(Ml2Plugin, self).delete_subnet(context, id)
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LOG.debug("Deleting subnet %s", id)
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session = context.session
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deallocated = set()
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while True:
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# NOTE(kevinbenton): this loop keeps db objects in scope
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# so we must expire them or risk stale reads.
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# see bug/1623990
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session.expire_all()
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with session.begin(subtransactions=True):
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record = self._get_subnet(context, id)
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subnet = self._make_subnet_dict(record, None, context=context)
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qry_allocated = (session.query(models_v2.IPAllocation).
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filter_by(subnet_id=id).
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join(models_v2.Port))
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is_auto_addr_subnet = ipv6_utils.is_auto_address_subnet(subnet)
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# Remove network owned ports, and delete IP allocations
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# for IPv6 addresses which were automatically generated
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# via SLAAC
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if is_auto_addr_subnet:
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self._subnet_check_ip_allocations_internal_router_ports(
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context, id)
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else:
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qry_allocated = (
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qry_allocated.filter(models_v2.Port.device_owner.
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in_(db_base_plugin_v2.AUTO_DELETE_PORT_OWNERS)))
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allocated = set(qry_allocated.all())
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LOG.debug("Ports to auto-deallocate: %s", allocated)
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if not is_auto_addr_subnet:
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user_alloc = self._subnet_get_user_allocation(
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context, id)
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if user_alloc:
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LOG.info(_LI("Found port (%(port_id)s, %(ip)s) "
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"having IP allocation on subnet "
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"%(subnet)s, cannot delete"),
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{'ip': user_alloc.ip_address,
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'port_id': user_alloc.port_id,
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'subnet': id})
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raise exc.SubnetInUse(subnet_id=id)
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db_base_plugin_v2._check_subnet_not_used(context, id)
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# SLAAC allocations currently can not be removed using
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# update_port workflow, and will persist in 'allocated'.
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# So for now just make sure update_port is called once for
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# them so MechanismDrivers is aware of the change.
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# This way SLAAC allocation is deleted by FK on subnet deletion
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# TODO(pbondar): rework update_port workflow to allow deletion
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# of SLAAC allocation via update_port.
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to_deallocate = allocated - deallocated
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# If to_deallocate is blank, then all known IPAllocations
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# (except SLAAC allocations) were correctly deleted
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# during the previous pass.
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# Check if there are more IP allocations, unless
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# is_auto_address_subnet is True. If transaction isolation
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# level is set to READ COMMITTED allocations made
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# concurrently will be returned by this query and transaction
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# will be restarted. It works for REPEATABLE READ isolation
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# level too because this query is executed only once during
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# transaction, and if concurrent allocations are detected
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# transaction gets restarted. Executing this query second time
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# in transaction would result in not seeing allocations
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# committed by concurrent transactions.
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if not to_deallocate:
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if (not is_auto_addr_subnet and
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self._subnet_check_ip_allocations(context, id)):
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# allocation found and it was DHCP port
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# that appeared after autodelete ports were
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# removed - continue iteration to find offending port
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# to update or raise SubnetInUse
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continue
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@registry.receives(resources.SUBNET, [events.PRECOMMIT_DELETE])
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def _subnet_delete_precommit_handler(self, rtype, event, trigger,
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context, subnet_id, **kwargs):
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record = self._get_subnet(context, subnet_id)
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subnet = self._make_subnet_dict(record, context=context)
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network = self.get_network(context, subnet['network_id'])
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mech_context = driver_context.SubnetContext(self, context,
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subnet,
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network)
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self.mechanism_manager.delete_subnet_precommit(
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mech_context)
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subnet, network)
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# TODO(kevinbenton): move this mech context into something like
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# a 'delete context' so it's not polluting the real context object
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setattr(context, '_mech_context', mech_context)
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self.mechanism_manager.delete_subnet_precommit(mech_context)
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LOG.debug("Deleting subnet record")
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session.delete(record)
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# The super(Ml2Plugin, self).delete_subnet() is not called,
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# so need to manually call delete_subnet for pluggable ipam
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self.ipam.delete_subnet(context, id)
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LOG.debug("Committing transaction")
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break
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for a in to_deallocate:
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if a.port:
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# calling update_port() for each allocation to remove the
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# IP from the port and call the MechanismDrivers
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fixed_ips = [{'subnet_id': ip.subnet_id,
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'ip_address': ip.ip_address}
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for ip in a.port.fixed_ips
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if ip.subnet_id != id]
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# By default auto-addressed ips are not removed from port
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# on port update, so mark subnet with 'delete_subnet' flag
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# to force ip deallocation on port update.
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if is_auto_addr_subnet:
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fixed_ips.append({'subnet_id': id,
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'delete_subnet': True})
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data = {attributes.PORT: {'fixed_ips': fixed_ips}}
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@registry.receives(resources.SUBNET, [events.AFTER_DELETE])
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def _subnet_delete_after_delete_handler(self, rtype, event, trigger,
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context, subnet, **kwargs):
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try:
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# NOTE Don't inline port_id; needed for PortNotFound.
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port_id = a.port_id
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self.update_port(context, port_id, data)
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except exc.PortNotFound:
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# NOTE Attempting to access a.port_id here is an error.
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LOG.debug("Port %s deleted concurrently", port_id)
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except exc.SubnetNotFound:
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# NOTE we hit here if another subnet was concurrently
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# removed that the port has a fixed_ip on. we just
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# continue so the loop re-iterates and the IPs are
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# looked up again
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continue
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except Exception as e:
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with excutils.save_and_reraise_exception():
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utils.attach_exc_details(
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e, _LE("Exception deleting fixed_ip from "
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"port %s"), port_id)
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deallocated.add(a)
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kwargs = {'context': context, 'subnet': subnet}
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registry.notify(resources.SUBNET, events.AFTER_DELETE, self, **kwargs)
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try:
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self.mechanism_manager.delete_subnet_postcommit(mech_context)
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self.mechanism_manager.delete_subnet_postcommit(
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context._mech_context)
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except ml2_exc.MechanismDriverError:
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# TODO(apech) - One or more mechanism driver failed to
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# delete the subnet. Ideally we'd notify the caller of
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@ -515,7 +515,7 @@ class TestMl2SubnetsV2(test_plugin.TestSubnetsV2,
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subnet_id = subnet['subnet']['id']
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attempt = [0]
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def check_and_create_ports(context, subnet_id):
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def create_dhcp_port(*args, **kwargs):
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"""A method to emulate race condition.
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Adds dhcp port in the middle of subnet delete
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@ -534,26 +534,17 @@ class TestMl2SubnetsV2(test_plugin.TestSubnetsV2,
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port_req = self.new_create_request('ports', data)
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port_res = port_req.get_response(self.api)
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self.assertEqual(201, port_res.status_int)
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return (context.session.query(models_v2.IPAllocation).
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filter_by(subnet_id=subnet_id).
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join(models_v2.Port).first())
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plugin = directory.get_plugin()
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# we mock _subnet_check_ip_allocations with method
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# that creates DHCP port 'in the middle' of subnet_delete
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# causing retry this way subnet is deleted on the
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# second attempt
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with mock.patch.object(plugin, '_subnet_check_ip_allocations',
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side_effect=check_and_create_ports):
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registry.subscribe(create_dhcp_port, resources.SUBNET,
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events.PRECOMMIT_DELETE)
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req = self.new_delete_request('subnets', subnet_id)
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res = req.get_response(self.api)
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self.assertEqual(204, res.status_int)
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# Validate chat check is called twice, i.e. after the
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# first check transaction gets restarted.
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calls = [mock.call(mock.ANY, subnet_id),
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mock.call(mock.ANY, subnet_id)]
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plugin._subnet_check_ip_allocations.assert_has_calls = (
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calls)
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self.assertEqual(1, attempt[0])
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def test_create_subnet_check_mtu_in_mech_context(self):
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plugin = directory.get_plugin()
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