cb15d34cc1
The method's return value is never used, only its side-effects are used. We rename it to reflect its actual usage, and remove the unused return value to avoid confusion. NOTE(mdbooth): The use of global state is a large part of what makes ImageCacheManager hard to read. I don't mean to imply with this change that's what should be done here, only to make it clearer to the reader that it is what's being done currently. Change-Id: Ic82f6d4f00fd1226673750538019339937a623bc
110 lines
4.2 KiB
Python
110 lines
4.2 KiB
Python
# Copyright 2013 OpenStack Foundation
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from nova.compute import task_states
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from nova.compute import vm_states
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import nova.conf
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from nova import objects
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from nova.virt import block_device as driver_block_device
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CONF = nova.conf.CONF
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class ImageCacheManager(object):
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"""Base class for the image cache manager.
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This class will provide a generic interface to the image cache manager.
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"""
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def __init__(self):
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self.remove_unused_base_images = CONF.remove_unused_base_images
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self.resize_states = [task_states.RESIZE_PREP,
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task_states.RESIZE_MIGRATING,
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task_states.RESIZE_MIGRATED,
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task_states.RESIZE_FINISH]
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def _get_base(self):
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"""Returns the base directory of the cached images."""
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raise NotImplementedError()
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def _list_running_instances(self, context, all_instances):
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"""List running instances (on all compute nodes).
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This method returns a dictionary with the following keys:
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- used_images
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- instance_names
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- used_swap_images
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"""
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used_images = {}
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instance_names = set()
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used_swap_images = set()
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instance_bdms = objects.BlockDeviceMappingList.bdms_by_instance_uuid(
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context, [instance.uuid for instance in all_instances])
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for instance in all_instances:
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# NOTE(mikal): "instance name" here means "the name of a directory
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# which might contain an instance" and therefore needs to include
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# historical permutations as well as the current one.
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instance_names.add(instance.name)
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instance_names.add(instance.uuid)
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if (instance.task_state in self.resize_states or
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instance.vm_state == vm_states.RESIZED):
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instance_names.add(instance.name + '_resize')
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instance_names.add(instance.uuid + '_resize')
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for image_key in ['image_ref', 'kernel_id', 'ramdisk_id']:
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image_ref_str = getattr(instance, image_key)
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if image_ref_str is None:
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continue
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local, remote, insts = used_images.get(image_ref_str,
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(0, 0, []))
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if instance.host == CONF.host:
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local += 1
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else:
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remote += 1
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insts.append(instance.name)
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used_images[image_ref_str] = (local, remote, insts)
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bdms = instance_bdms.get(instance.uuid)
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if bdms:
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swap = driver_block_device.convert_swap(bdms)
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if swap:
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swap_image = 'swap_' + str(swap[0]['swap_size'])
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used_swap_images.add(swap_image)
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return {'used_images': used_images,
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'instance_names': instance_names,
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'used_swap_images': used_swap_images}
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def _scan_base_images(self, base_dir):
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"""Scan base images present in base_dir and populate internal
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state.
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"""
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raise NotImplementedError()
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def _age_and_verify_cached_images(self, context, all_instances, base_dir):
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"""Ages and verifies cached images."""
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raise NotImplementedError()
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def update(self, context, all_instances):
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"""The cache manager.
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This will invoke the cache manager. This will update the cache
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according to the defined cache management scheme. The information
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populated in the cached stats will be used for the cache management.
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"""
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raise NotImplementedError()
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