neutron/neutron/scheduler/base_scheduler.py
Brian Haley eaf990b2bc Fix pep8 E128 warnings in non-test code
Reduces E128 warnings by ~260 to just ~900,
no way we're getting rid of all of them at once (or ever).
Files under neutron/tests still have a ton of E128 warnings.

Change-Id: I9137150ccf129bf443e33428267cd4bc9c323b54
Co-Authored-By: Akihiro Motoki <amotoki@gmail.com>
2019-03-12 21:22:33 +00:00

78 lines
2.8 KiB
Python

# Copyright (c) 2015 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.
import abc
from operator import attrgetter
import random
import six
@six.add_metaclass(abc.ABCMeta)
class BaseScheduler(object):
"""The base scheduler (agnostic to resource type).
Child classes of BaseScheduler must define the
self.resource_filter to filter agents of
particular type.
"""
resource_filter = None
@abc.abstractmethod
def select(self, plugin, context, resource_hostable_agents,
resource_hosted_agents, num_agents_needed):
"""Return a subset of agents based on the specific scheduling logic."""
def schedule(self, plugin, context, resource):
"""Select and bind agents to a given resource."""
if not self.resource_filter:
return
# filter the agents that can host the resource
filtered_agents_dict = self.resource_filter.filter_agents(
plugin, context, resource)
num_agents = filtered_agents_dict['n_agents']
hostable_agents = filtered_agents_dict['hostable_agents']
hosted_agents = filtered_agents_dict['hosted_agents']
chosen_agents = self.select(plugin, context, hostable_agents,
hosted_agents, num_agents)
# bind the resource to the agents
self.resource_filter.bind(context, chosen_agents, resource['id'])
return chosen_agents
class BaseChanceScheduler(BaseScheduler):
"""Choose agents randomly."""
def __init__(self, resource_filter):
self.resource_filter = resource_filter
def select(self, plugin, context, resource_hostable_agents,
resource_hosted_agents, num_agents_needed):
chosen_agents = random.sample(resource_hostable_agents,
num_agents_needed)
return chosen_agents
class BaseWeightScheduler(BaseScheduler):
"""Choose agents based on load."""
def __init__(self, resource_filter):
self.resource_filter = resource_filter
def select(self, plugin, context, resource_hostable_agents,
resource_hosted_agents, num_agents_needed):
chosen_agents = sorted(resource_hostable_agents,
key=attrgetter('load'))[0:num_agents_needed]
return chosen_agents