deb-sahara/sahara/service/coordinator.py
lcsong 8b4af0daf3 Remove log translations
Log messages are no longer being translated. This removes all use of
the _LE, _LI, _LW and _LC translation markers to simplify logging and to
avoid confusion with new contributions.

See:
http://lists.openstack.org/pipermail/openstack-i18n/2016-November/002574.html
http://lists.openstack.org/pipermail/openstack-dev/2017-March/113365.html

It will be a giant patch if all these _LE, _LI, _LW and _LC being deleted
within one patch, so this patch only delete _LI; _LW, _LC and _LE has been
handled in previous patchies. This is the last patch for sahara to delete
log translations.

Change-Id: I73e99ca7fd5bc0cd8df7cce30b5f12e00e70149c
2017-04-18 10:56:48 +08:00

131 lines
4.5 KiB
Python

# Copyright (c) 2015 Mirantis Inc.
#
# 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 bisect
import hashlib
from oslo_config import cfg
from oslo_log import log
from oslo_utils import uuidutils
from tooz import coordination
LOG = log.getLogger(__name__)
coordinator_opts = [
cfg.IntOpt('coordinator_heartbeat_interval',
default=1,
help='Interval size between heartbeat execution in seconds. '
'Heartbeats are executed to make sure that connection to '
'the coordination server is active.'),
cfg.IntOpt('hash_ring_replicas_count',
default=40,
help='Number of points that belongs to each member on a hash '
'ring. The larger number leads to a better distribution.')
]
CONF = cfg.CONF
CONF.register_opts(coordinator_opts)
class Coordinator(object):
def __init__(self, backend_url):
self.coordinator = None
self.member_id = uuidutils.generate_uuid()
if backend_url:
try:
self.coordinator = coordination.get_coordinator(
backend_url, self.member_id)
self.coordinator.start()
LOG.info('Coordination backend loaded successfully.')
except coordination.ToozError:
LOG.error('Error connecting to coordination backend.')
raise
def is_started(self):
if self.coordinator:
return self.coordinator.is_started
return False
def heartbeat(self):
if self.coordinator:
self.coordinator.heartbeat()
def join_group(self, group_id):
if self.coordinator:
try:
self.coordinator.join_group(group_id).get()
except coordination.GroupNotCreated:
try:
self.coordinator.create_group(group_id).get()
except coordination.GroupAlreadyExist:
pass
self.coordinator.join_group(group_id).get()
def get_members(self, group_id):
if self.coordinator:
for i in range(2):
try:
members = self.coordinator.get_members(group_id).get()
if self.member_id in members:
return members
self.join_group(group_id)
except coordination.GroupNotCreated:
self.join_group(group_id)
except coordination.ToozError as e:
LOG.error("Couldn't get members of {group} group. "
"Reason: {ex}".format(
group=group_id, ex=str(e)))
return []
class HashRing(Coordinator):
def __init__(self, backend_url, group_id):
self.group_id = group_id
self.replicas = CONF.hash_ring_replicas_count
super(HashRing, self).__init__(backend_url)
self.join_group(group_id)
@staticmethod
def _hash(key):
return int(hashlib.md5(str(key)).hexdigest(), 16) # nosec
def _build_ring(self):
ring = {}
members = self.get_members(self.group_id)
for member in members:
for r in range(self.replicas):
hashed_key = self._hash('%s:%s' % (member, r))
ring[hashed_key] = member
return ring, sorted(ring.keys())
def _check_object(self, object, ring, sorted_keys):
"""Checks if this object belongs to this member or not"""
hashed_key = self._hash(object.id)
position = bisect.bisect(sorted_keys, hashed_key)
position = position if position < len(sorted_keys) else 0
return ring[sorted_keys[position]] == self.member_id
def get_subset(self, objects):
"""Returns subset that belongs to this member"""
if self.coordinator:
ring, keys = self._build_ring()
if ring:
return [obj for obj in objects if self._check_object(
obj, ring, keys)]
return []
return objects