nova/nova/api/openstack/placement/util.py

420 lines
15 KiB
Python

# 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.
"""Utility methods for placement API."""
import functools
import re
import jsonschema
from oslo_middleware import request_id
from oslo_serialization import jsonutils
from oslo_utils import timeutils
from oslo_utils import uuidutils
import webob
from nova.api.openstack.placement import lib as placement_lib
# NOTE(cdent): avoid cyclical import conflict between util and
# microversion
import nova.api.openstack.placement.microversion
from nova.i18n import _
# Querystring-related constants
_QS_RESOURCES = 'resources'
_QS_REQUIRED = 'required'
_QS_KEY_PATTERN = re.compile(
r"^(%s)([1-9][0-9]*)?$" % '|'.join((_QS_RESOURCES, _QS_REQUIRED)))
# NOTE(cdent): This registers a FormatChecker on the jsonschema
# module. Do not delete this code! Although it appears that nothing
# is using the decorated method it is being used in JSON schema
# validations to check uuid formatted strings.
@jsonschema.FormatChecker.cls_checks('uuid')
def _validate_uuid_format(instance):
return uuidutils.is_uuid_like(instance)
def check_accept(*types):
"""If accept is set explicitly, try to follow it.
If there is no match for the incoming accept header
send a 406 response code.
If accept is not set send our usual content-type in
response.
"""
def decorator(f):
@functools.wraps(f)
def decorated_function(req):
if req.accept:
best_match = req.accept.best_match(types)
if not best_match:
type_string = ', '.join(types)
raise webob.exc.HTTPNotAcceptable(
_('Only %(type)s is provided') % {'type': type_string},
json_formatter=json_error_formatter)
return f(req)
return decorated_function
return decorator
def extract_json(body, schema):
"""Extract JSON from a body and validate with the provided schema."""
try:
data = jsonutils.loads(body)
except ValueError as exc:
raise webob.exc.HTTPBadRequest(
_('Malformed JSON: %(error)s') % {'error': exc},
json_formatter=json_error_formatter)
try:
jsonschema.validate(data, schema,
format_checker=jsonschema.FormatChecker())
except jsonschema.ValidationError as exc:
raise webob.exc.HTTPBadRequest(
_('JSON does not validate: %(error)s') % {'error': exc},
json_formatter=json_error_formatter)
return data
def inventory_url(environ, resource_provider, resource_class=None):
url = '%s/inventories' % resource_provider_url(environ, resource_provider)
if resource_class:
url = '%s/%s' % (url, resource_class)
return url
def json_error_formatter(body, status, title, environ):
"""A json_formatter for webob exceptions.
Follows API-WG guidelines at
http://specs.openstack.org/openstack/api-wg/guidelines/errors.html
"""
# Clear out the html that webob sneaks in.
body = webob.exc.strip_tags(body)
# Get status code out of status message. webob's error formatter
# only passes entire status string.
status_code = int(status.split(None, 1)[0])
error_dict = {
'status': status_code,
'title': title,
'detail': body
}
# If the request id middleware has had a chance to add an id,
# put it in the error response.
if request_id.ENV_REQUEST_ID in environ:
error_dict['request_id'] = environ[request_id.ENV_REQUEST_ID]
# When there is a no microversion in the environment and a 406,
# microversion parsing failed so we need to include microversion
# min and max information in the error response.
microversion = nova.api.openstack.placement.microversion
if status_code == 406 and microversion.MICROVERSION_ENVIRON not in environ:
error_dict['max_version'] = microversion.max_version_string()
error_dict['min_version'] = microversion.min_version_string()
return {'errors': [error_dict]}
def pick_last_modified(last_modified, obj):
"""Choose max of last_modified and obj.updated_at or obj.created_at.
If updated_at is not implemented in `obj` use the current time in UTC.
"""
try:
current_modified = (obj.updated_at or obj.created_at)
except NotImplementedError:
# If updated_at is not implemented, we are looking at objects that
# have not come from the database, so "now" is the right modified
# time.
current_modified = timeutils.utcnow(with_timezone=True)
if last_modified:
last_modified = max(last_modified, current_modified)
else:
last_modified = current_modified
return last_modified
def require_content(content_type):
"""Decorator to require a content type in a handler."""
def decorator(f):
@functools.wraps(f)
def decorated_function(req):
if req.content_type != content_type:
# webob's unset content_type is the empty string so
# set it the error message content to 'None' to make
# a useful message in that case. This also avoids a
# KeyError raised when webob.exc eagerly fills in a
# Template for output we will never use.
if not req.content_type:
req.content_type = 'None'
raise webob.exc.HTTPUnsupportedMediaType(
_('The media type %(bad_type)s is not supported, '
'use %(good_type)s') %
{'bad_type': req.content_type,
'good_type': content_type},
json_formatter=json_error_formatter)
else:
return f(req)
return decorated_function
return decorator
def resource_class_url(environ, resource_class):
"""Produce the URL for a resource class.
If SCRIPT_NAME is present, it is the mount point of the placement
WSGI app.
"""
prefix = environ.get('SCRIPT_NAME', '')
return '%s/resource_classes/%s' % (prefix, resource_class.name)
def resource_provider_url(environ, resource_provider):
"""Produce the URL for a resource provider.
If SCRIPT_NAME is present, it is the mount point of the placement
WSGI app.
"""
prefix = environ.get('SCRIPT_NAME', '')
return '%s/resource_providers/%s' % (prefix, resource_provider.uuid)
def trait_url(environ, trait):
"""Produce the URL for a trait.
If SCRIPT_NAME is present, it is the mount point of the placement
WSGI app.
"""
prefix = environ.get('SCRIPT_NAME', '')
return '%s/traits/%s' % (prefix, trait.name)
def validate_query_params(req, schema):
try:
# NOTE(Kevin_Zheng): The webob package throws UnicodeError when
# param cannot be decoded. Catch this and raise HTTP 400.
jsonschema.validate(dict(req.GET), schema,
format_checker=jsonschema.FormatChecker())
except (jsonschema.ValidationError, UnicodeDecodeError) as exc:
raise webob.exc.HTTPBadRequest(
_('Invalid query string parameters: %(exc)s') %
{'exc': exc})
def wsgi_path_item(environ, name):
"""Extract the value of a named field in a URL.
Return None if the name is not present or there are no path items.
"""
# NOTE(cdent): For the time being we don't need to urldecode
# the value as the entire placement API has paths that accept no
# encoded values.
try:
return environ['wsgiorg.routing_args'][1][name]
except (KeyError, IndexError):
return None
def normalize_resources_qs_param(qs):
"""Given a query string parameter for resources, validate it meets the
expected format and return a dict of amounts, keyed by resource class name.
The expected format of the resources parameter looks like so:
$RESOURCE_CLASS_NAME:$AMOUNT,$RESOURCE_CLASS_NAME:$AMOUNT
So, if the user was looking for resource providers that had room for an
instance that will consume 2 vCPUs, 1024 MB of RAM and 50GB of disk space,
they would use the following query string:
?resources=VCPU:2,MEMORY_MB:1024,DISK_GB:50
The returned value would be:
{
"VCPU": 2,
"MEMORY_MB": 1024,
"DISK_GB": 50,
}
:param qs: The value of the 'resources' query string parameter
:raises `webob.exc.HTTPBadRequest` if the parameter's value isn't in the
expected format.
"""
if qs.strip() == "":
msg = _('Badly formed resources parameter. Expected resources '
'query string parameter in form: '
'?resources=VCPU:2,MEMORY_MB:1024. Got: empty string.')
raise webob.exc.HTTPBadRequest(msg)
result = {}
resource_tuples = qs.split(',')
for rt in resource_tuples:
try:
rc_name, amount = rt.split(':')
except ValueError:
msg = _('Badly formed resources parameter. Expected resources '
'query string parameter in form: '
'?resources=VCPU:2,MEMORY_MB:1024. Got: %s.')
msg = msg % rt
raise webob.exc.HTTPBadRequest(msg)
try:
amount = int(amount)
except ValueError:
msg = _('Requested resource %(resource_name)s expected positive '
'integer amount. Got: %(amount)s.')
msg = msg % {
'resource_name': rc_name,
'amount': amount,
}
raise webob.exc.HTTPBadRequest(msg)
if amount < 1:
msg = _('Requested resource %(resource_name)s requires '
'amount >= 1. Got: %(amount)d.')
msg = msg % {
'resource_name': rc_name,
'amount': amount,
}
raise webob.exc.HTTPBadRequest(msg)
result[rc_name] = amount
return result
def normalize_traits_qs_param(val):
"""Parse a traits query string parameter value.
Note that this method doesn't know or care about the query parameter key,
which may currently be of the form `required`, `required123`, etc., but
which may someday also include `preferred`, etc.
This method currently does no format validation of trait strings, other
than to ensure they're not zero-length.
:param val: A traits query parameter value: a comma-separated string of
trait names.
:return: A set of trait names.
:raises `webob.exc.HTTPBadRequest` if the val parameter is not in the
expected format.
"""
ret = set(substr.strip() for substr in val.split(','))
if not all(trait for trait in ret):
msg = _('Invalid query string parameters: Expected \'required\' '
'parameter value of the form: HW_CPU_X86_VMX,CUSTOM_MAGIC. '
'Got: "%s"') % val
raise webob.exc.HTTPBadRequest(msg)
return ret
def parse_qs_request_groups(qsdict):
"""Parse numbered resources and traits groupings out of a querystring dict.
The input qsdict represents a query string of the form:
?resources=$RESOURCE_CLASS_NAME:$AMOUNT,$RESOURCE_CLASS_NAME:$AMOUNT
&required=$TRAIT_NAME,$TRAIT_NAME
&resources1=$RESOURCE_CLASS_NAME:$AMOUNT,RESOURCE_CLASS_NAME:$AMOUNT
&required1=$TRAIT_NAME,$TRAIT_NAME
&resources2=$RESOURCE_CLASS_NAME:$AMOUNT,RESOURCE_CLASS_NAME:$AMOUNT
&required2=$TRAIT_NAME,$TRAIT_NAME
These are parsed in groups according to the numeric suffix of the key.
For each group, a RequestGroup instance is created containing that group's
resources and required traits. For the (single) group with no suffix, the
RequestGroup.use_same_provider attribute is False; for the numbered groups
it is True.
The return is a list of these RequestGroup instances.
As an example, if qsdict represents the query string:
?resources=VCPU:2,MEMORY_MB:1024,DISK_GB=50
&required=HW_CPU_X86_VMX,CUSTOM_STORAGE_RAID
&resources1=SRIOV_NET_VF:2
&required1=CUSTOM_PHYSNET_PUBLIC,CUSTOM_SWITCH_A
&resources2=SRIOV_NET_VF:1
&required2=CUSTOM_PHYSNET_PRIVATE
...the return value will be:
[ RequestGroup(
use_same_provider=False,
resources={
"VCPU": 2,
"MEMORY_MB": 1024,
"DISK_GB" 50,
},
required_traits=[
"HW_CPU_X86_VMX",
"CUSTOM_STORAGE_RAID",
],
),
RequestGroup(
use_same_provider=True,
resources={
"SRIOV_NET_VF": 2,
},
required_traits=[
"CUSTOM_PHYSNET_PUBLIC",
"CUSTOM_SWITCH_A",
],
),
RequestGroup(
use_same_provider=True,
resources={
"SRIOV_NET_VF": 1,
},
required_traits=[
"CUSTOM_PHYSNET_PRIVATE",
],
),
]
:param qsdict: The MultiDict representing the querystring on a GET.
:return: A list of RequestGroup instances.
:raises `webob.exc.HTTPBadRequest` if any value is malformed, or if a
trait list is given without corresponding resources.
"""
# Temporary dict of the form: { suffix: RequestGroup }
by_suffix = {}
def get_request_group(suffix):
if suffix not in by_suffix:
rq_grp = placement_lib.RequestGroup(use_same_provider=bool(suffix))
by_suffix[suffix] = rq_grp
return by_suffix[suffix]
for key, val in qsdict.items():
match = _QS_KEY_PATTERN.match(key)
if not match:
continue
# `prefix` is 'resources' or 'required'
# `suffix` is an integer string, or None
prefix, suffix = match.groups()
request_group = get_request_group(suffix or '')
if prefix == _QS_RESOURCES:
request_group.resources = normalize_resources_qs_param(val)
elif prefix == _QS_REQUIRED:
request_group.required_traits = normalize_traits_qs_param(val)
# Ensure any group with 'required' also has 'resources'.
orphans = [('required%s' % suff) for suff, group in by_suffix.items()
if group.required_traits and not group.resources]
if orphans:
msg = _('All traits parameters must be associated with resources. '
'Found the following orphaned traits keys: %s')
raise webob.exc.HTTPBadRequest(msg % ', '.join(orphans))
# NOTE(efried): The sorting is not necessary for the API, but it makes
# testing easier.
return [by_suffix[suff] for suff in sorted(by_suffix)]