neutron-lib/neutron_lib/placement/utils.py
Bence Romsics 579e0ccabb Placement: utils
* to generate Placement trait names,
* to generate Placement resource provider UUIDs, and
* to uniformly parse and validate Placement-related config options in
  all agents.

Change-Id: I192d99673feba97a95af995923b266e2f8b58c6d
Needed-By: https://review.openstack.org/577223
Partial-Bug: #1578989
See-Also: https://review.openstack.org/502306 (nova spec)
See-Also: https://review.openstack.org/508149 (neutron spec)
2018-08-21 16:52:30 +02:00

244 lines
8.7 KiB
Python

# Copyright 2018 Ericsson
#
# 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 uuid
import os_traits
from oslo_log import log as logging
import six
from neutron_lib._i18n import _
from neutron_lib import constants as const
from neutron_lib.placement import constants as place_const
LOG = logging.getLogger(__name__)
def physnet_trait(physnet):
"""A Placement trait name to represent being connected to a physnet.
:param physnet: The physnet name.
:returns: The trait name representing the physnet.
"""
return os_traits.normalize_name('%s%s' % (
place_const.TRAIT_PREFIX_PHYSNET, physnet))
def vnic_type_trait(vnic_type):
"""A Placement trait name to represent support for a vnic_type.
:param physnet: The vnic_type.
:returns: The trait name representing the vnic_type.
"""
return os_traits.normalize_name('%s%s' % (
place_const.TRAIT_PREFIX_VNIC_TYPE, vnic_type))
def six_uuid5(namespace, name):
"""A uuid.uuid5 variant that takes utf-8 'name' both in Python 2 and 3.
:param namespace: A UUID object used as a namespace in the generation of a
v5 UUID.
:param name: Any string (either bytecode or unicode) used as a name in the
generation of a v5 UUID.
:returns: A v5 UUID object.
"""
# NOTE(bence romsics):
# uuid.uuid5() behaves seemingly consistently but still incompatibly
# different in cPython 2 and 3. Both expects the 'name' parameter to have
# the type of the default string literal in each language version.
# That is:
# The cPython 2 variant expects a byte string.
# The cPython 3 variant expects a unicode string.
# Which types are called respectively 'str' and 'str' for the sake of
# confusion. But the sha1() hash inside uuid5() always needs a byte string,
# so we have to treat the two versions asymmetrically. See also:
#
# cPython 2.7:
# https://github.com/python/cpython/blob
# /ea9a0994cd0f4bd37799b045c34097eb21662b3d/Lib/uuid.py#L603
# cPython 3.6:
# https://github.com/python/cpython/blob
# /e9e2fd75ccbc6e9a5221cf3525e39e9d042d843f/Lib/uuid.py#L628
if six.PY2:
name = name.encode('utf-8')
return uuid.uuid5(namespace=namespace, name=name)
# NOTE(bence romsics): The spec said: "Agent resource providers shall
# be identified by their already existing Neutron agent UUIDs [...]"
#
# https://review.openstack.org/#/c/508149/14/specs/rocky
# /minimum-bandwidth-allocation-placement-api.rst@465
#
# However we forgot that agent UUIDs are not stable through a few
# admin operations like after a manual 'openstack network agent
# delete'. Here we make up a stable UUID instead.
def agent_resource_provider_uuid(namespace, host):
"""Generate a stable UUID for an agent.
:param namespace: A UUID object identifying a mechanism driver (including
its agent).
:param host: The hostname of the agent.
:returns: A unique and stable UUID identifying an agent.
"""
return six_uuid5(namespace=namespace, name=host)
def device_resource_provider_uuid(namespace, host, device, separator=':'):
"""Generate a stable UUID for a physical network device.
:param namespace: A UUID object identifying a mechanism driver (including
its agent).
:param host: The hostname of the agent.
:param device: A host-unique name of the physical network device.
:param separator: A string used in assembling a name for uuid5(). Choose
one that cannot occur either in 'host' or 'device'.
Optional.
:returns: A unique and stable UUID identifying a physical network device.
"""
name = separator.join([host, device])
return six_uuid5(namespace=namespace, name=name)
def _parse_bandwidth_value(bw_str):
"""Parse the config string of a bandwidth value to an integer.
:param bw_str: A decimal string represantation of an integer, allowing
the empty string.
:raises: ValueError on invalid input.
:returns: The bandwidth value as an integer or None if not set in config.
"""
try:
bw = None
if bw_str:
bw = int(bw_str)
if bw < 0:
raise ValueError()
except ValueError:
raise ValueError(_(
'Cannot parse resource_provider_bandwidths. '
'Expected: non-negative integer bandwidth value, got: %s') %
bw_str)
return bw
def parse_rp_bandwidths(bandwidths):
"""Parse and validate config option: resource_provider_bandwidths.
Input in the config:
resource_provider_bandwidths = eth0:10000:10000,eth1::10000,eth2::,eth3
Input here:
['eth0:10000:10000', 'eth1::10000', 'eth2::', 'eth3']
Output:
{
'eth0': {'egress': 10000, 'ingress': 10000},
'eth1': {'egress': None, 'ingress': 10000},
'eth2': {'egress': None, 'ingress': None},
'eth3': {'egress': None, 'ingress': None},
}
:param bandwidths: The list of 'interface:egress:ingress' bandwidth
config options as pre-parsed by oslo_config.
:raises: ValueError on invalid input.
:returns: The fully parsed bandwidth config as a dict of dicts.
"""
rv = {}
for bandwidth in bandwidths:
if ':' not in bandwidth:
bandwidth += '::'
try:
device, egress_str, ingress_str = bandwidth.split(':')
except ValueError:
raise ValueError(_(
'Cannot parse resource_provider_bandwidths. '
'Expected: DEVICE:EGRESS:INGRESS, got: %s') % bandwidth)
if device in rv:
raise ValueError(_(
'Cannot parse resource_provider_bandwidths. '
'Same device listed multiple times: %s') % device)
egress = _parse_bandwidth_value(egress_str)
ingress = _parse_bandwidth_value(ingress_str)
rv[device] = {
const.EGRESS_DIRECTION: egress,
const.INGRESS_DIRECTION: ingress,
}
return rv
def parse_rp_inventory_defaults(inventory_defaults):
"""Parse and validate config option: parse_rp_inventory_defaults.
Cast the dict values to the proper numerical types.
Input in the config:
resource_provider_inventory_defaults = allocation_ratio:1.0,min_unit:1
Input here:
{
'allocation_ratio': '1.0',
'min_unit': '1',
}
Output here:
{
'allocation_ratio': 1.0,
'min_unit': 1,
}
:param inventory_defaults: The dict of inventory parameters and values (as
strings) as pre-parsed by oslo_config.
:raises: ValueError on invalid input.
:returns: The fully parsed inventory parameters and values (as numerical
values) as a dict.
"""
unexpected_options = (set(inventory_defaults.keys()) -
place_const.INVENTORY_OPTIONS)
if unexpected_options:
raise ValueError(_(
'Cannot parse inventory_defaults. Unexpected options: %s') %
','.join(unexpected_options))
# allocation_ratio is a float
try:
if 'allocation_ratio' in inventory_defaults:
inventory_defaults['allocation_ratio'] = float(
inventory_defaults['allocation_ratio'])
if inventory_defaults['allocation_ratio'] < 0:
raise ValueError()
except ValueError:
raise ValueError(_(
'Cannot parse inventory_defaults.allocation_ratio. '
'Expected: non-negative float, got: %s') %
inventory_defaults['allocation_ratio'])
# the others are ints
for key in ('min_unit', 'max_unit', 'reserved', 'step_size'):
try:
if key in inventory_defaults:
inventory_defaults[key] = int(inventory_defaults[key])
if inventory_defaults[key] < 0:
raise ValueError()
except ValueError:
raise ValueError(_(
'Cannot parse inventory_defaults.%(key)s. '
'Expected: non-negative int, got: %(got)s') % {
'key': key,
'got': inventory_defaults[key],
})
return inventory_defaults