DEPRECATED, Neutron integration with OVN
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# Copyright 2019 Red Hat, 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
# 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 datetime
from oslo_log import log
from oslo_utils import timeutils
import six
from tooz import hashring
from networking_ovn.common import constants
from networking_ovn.common import exceptions
from networking_ovn.db import hash_ring as db_hash_ring
LOG = log.getLogger(__name__)
class HashRingManager(object):
def __init__(self):
self._hash_ring = None
self._last_time_loaded = None
self._cache_startup_timeout = True
def _wait_startup_before_caching(self):
# NOTE(lucasagomes): Some events are processed at the service's
# startup time and since many services may be started concurrently
# we do not want to use a cached hash ring at that point. This
# method checks if the created_at and updated_at columns from the
# nodes in the ring from this host is equal, and if so it means
# that the service just started.
# If the startup timeout already expired, there's no reason to
# keep reading from the DB. At this point this will always
# return False
if not self._cache_startup_timeout:
return False
nodes = db_hash_ring.get_active_nodes(
constants.HASH_RING_CACHE_TIMEOUT, from_host=True)
dont_cache = nodes and nodes[0].created_at == nodes[0].updated_at
if not dont_cache:
self._cache_startup_timeout = False
return dont_cache
def _load_hash_ring(self, refresh=False):
cache_timeout = timeutils.utcnow() - datetime.timedelta(
# Refresh the cache if:
# - Refreshed is forced (refresh=True)
# - Service just started (_wait_startup_before_caching)
# - Hash Ring is not yet instantiated
# - Cache has timed out
if (refresh or
self._wait_startup_before_caching or
self._hash_ring is None or
not self._hash_ring.nodes or
cache_timeout >= self._last_time_loaded):
nodes = db_hash_ring.get_active_nodes(
self._hash_ring = hashring.HashRing({node.node_uuid
for node in nodes})
self._last_time_loaded = timeutils.utcnow()
def refresh(self):
def get_node(self, key):
# tooz expects a byte string for the hash
if isinstance(key, six.string_types):
key = key.encode('utf-8')
# We need to pop the value from the set. If empty,
# KeyError is raised
return self._hash_ring[key].pop()
except KeyError:
raise exceptions.HashRingIsEmpty(key=key)