Add filter rule engine to process filter query
Added filter rule engine to process filter query parameter as defined in ETSI GS NFV-SOL 013 V2.6.1 (2019-03), section 5.2 `Attribute-based filtering`. For example, Request: GET .../vnfpkgm/v1/vnf_packages/filter=(eq,onboardingState,CREATED) It will return list of vnf packages matching `onboardingState` to `CREATED`. The concept of filter rule engine is based on the oslo.policy rule engine. Change-Id: I25bd70291b93b734148d19740536065b10aaf524 Implements: bp/enhance-vnf-package-support-part1
This commit is contained in:
tpatil
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12badc2455
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# -*- coding: utf-8 -*-
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#
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# Copyright (c) 2020 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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import abc
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from oslo_utils import strutils
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from oslo_utils import timeutils
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from oslo_utils import uuidutils
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import six
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from tacker.common import exceptions as exception
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registered_filters = {}
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SUPPORTED_OP_ONE = ['eq', 'neq', 'gt', 'lt', 'gte', 'lte']
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SUPPORTED_OP_MULTI = ['in', 'nin', 'cont', 'ncont']
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@six.add_metaclass(abc.ABCMeta)
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class BaseFilter(object):
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"""Abstract base class for Filter classes."""
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@abc.abstractmethod
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def __str__(self):
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"""String representation of the filter tree rooted at this node."""
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pass
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@abc.abstractmethod
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def __call__(self, target):
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"""Triggers if instance of the class is called.
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Performs the checks against operators, attribute and datatype
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of the value. Raises exception if it's invalid and finally attribute
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is mapped to the database model that's present in the target dict.
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"""
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pass
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class Filter(BaseFilter):
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SUPPORTED_OPERATORS = None
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FILTER_OPERATOR_SPEC_MAPPING = {
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'eq': '==',
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'neq': '!=',
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'in': 'in',
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'nin': 'not_in',
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'gt': '>',
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'gte': '>=',
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'lt': '<',
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'lte': '<=',
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'cont': 'in',
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'ncont': 'not_in'
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}
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OPERATOR_SUPPORTED_DATA_TYPES = {
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'eq': ['string', 'number', 'enum', 'boolean', 'key_value_pair'],
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'neq': ['string', 'number', 'enum', 'boolean', 'key_value_pair'],
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'in': ['string', 'number', 'enum', 'key_value_pair'],
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'nin': ['string', 'number', 'enum', 'key_value_pair'],
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'gt': ['string', 'number', 'datetime', 'key_value_pair'],
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'gte': ['string', 'number', 'datetime', 'key_value_pair'],
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'lt': ['string', 'number', 'datetime', 'key_value_pair'],
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'lte': ['string', 'number', 'datetime', 'key_value_pair'],
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'cont': ['string', 'key_value_pair'],
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'ncont': ['string', 'key_value_pair'],
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}
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def __init__(self, operator, attribute, values):
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self.operator = operator
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self.attribute = attribute
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self.values = values
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def __str__(self):
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"""Return a string representation of this filter."""
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return '%s,%s,%s' % (self.operator, self.attribute,
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",".join(self.values))
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def _attribute_special_field(self, target):
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"""Check if an attribute is a special field in the target
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Look for attributes in the target that ends with '*' as
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these are special attributes whose type could be 'key_value'
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which requires special treatment. For example
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if attribute in target is 'userDefinedData/*' and if self.attribute
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is userDefinedData/key1, then it's valid even though there is no
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exact match in the target because key/value pair values are
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dynamic.
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"""
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special_attributes = [attribute for attribute in target.keys() if '*'
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in attribute]
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for attribute in special_attributes:
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field = attribute.split('*')[0]
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if self.attribute.startswith(field):
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return attribute
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def _validate_operators(self):
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if not self.operator:
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msg = ("Rule '%(rule)s' cannot contain operator")
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raise exception.ValidationError(msg % {"rule": self})
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if self.SUPPORTED_OPERATORS and self.operator not in \
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self.SUPPORTED_OPERATORS:
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msg = ("Rule '%(rule)s' contains invalid operator "
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"'%(operator)s'")
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raise exception.ValidationError(msg % {"rule": self,
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"operator": self.operator})
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def _validate_attribute_name(self, target):
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if not self.attribute:
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msg = ("Rule '%(rule)s' doesn't contain attribute name")
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raise exception.ValidationError(msg % {"rule": self})
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if '*' in self.attribute:
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msg = ("Rule '%(rule)s' contains invalid attribute name "
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"'%(attribute)s'")
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raise exception.ValidationError(msg % {"rule": self,
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"attribute": self.attribute})
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if target and self.attribute not in target:
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if not self._attribute_special_field(target):
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msg = ("Rule '%(rule)s' contains invalid attribute name "
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"'%(attribute)s'")
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raise exception.ValidationError(msg % {"rule": self,
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"attribute": self.attribute})
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def _handle_string(self, value):
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if value[0] == "'" and value[-1] == "'":
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value = value.strip("'")
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# The logic below enforces single quotes to be in pairs.
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# Raises exception otherwise. It also replaces a pair of
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# single quotes with one single quote.
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# NFV_SOL013 Section 5.2.2
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num_quotes = value.count("'")
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value = value.replace("''", "'")
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if (value.count("'") * 2) != num_quotes:
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msg = ("Rule '%(rule)s' value doesn't have single "
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"quotes in pairs")
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raise exception.ValidationError(msg % {"rule": self})
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elif any(c in value for c in [",", ")", "'"]):
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msg = ("Rule '%(rule)s' value must be enclosed in "
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"single quotes when it contains either of "
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"comma, single quote, closing bracket")
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raise exception.ValidationError(msg % {"rule": self})
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return value
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def _handle_values(self, target):
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special_attribute = self._attribute_special_field(target)
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if special_attribute:
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attribute_info = target.get(special_attribute)
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else:
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attribute_info = target.get(self.attribute)
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if attribute_info[1] in ['string', 'key_value_pair']:
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values = [self._handle_string(v) for v in self.values]
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self.values = values
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def _validate_data_type(self, target):
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if not self.values:
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msg = ("Rule '%(rule)s' contains empty value")
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raise exception.ValidationError(msg % {"rule": self})
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special_attribute = self._attribute_special_field(target)
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if special_attribute:
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attribute_info = target.get(special_attribute)
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else:
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attribute_info = target.get(self.attribute)
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for value in self.values:
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error = False
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if attribute_info[1] == 'string' and not isinstance(value,
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six.string_types):
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error = True
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elif attribute_info[1] == 'number':
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if not strutils.is_int_like(value):
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error = True
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elif attribute_info[1] == 'uuid':
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if not uuidutils.is_uuid_like(value):
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error = True
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elif attribute_info[1] == 'datetime':
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try:
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timeutils.parse_isotime(value)
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except ValueError:
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error = True
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elif attribute_info[1] == 'enum':
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if value not in attribute_info[3]:
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msg = ("Rule '%(rule)s' contains data type '%(type)s' "
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"with invalid value. It should be one of "
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"%(valid_value)s")
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raise exception.ValidationError(msg % {"rule": self,
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"valid_value": ",".join(attribute_info[3]),
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'type': attribute_info[1]})
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if error:
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msg = ("Rule '%(rule)s' contains invalid data type for value "
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"'%(value)s'. The data type should be '%(type)s'")
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raise exception.ValidationError(msg % {"rule": self,
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"value": value,
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'type': attribute_info[1]})
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# Also, check whether the data type is supported by operator
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if attribute_info[1] not in \
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self.OPERATOR_SUPPORTED_DATA_TYPES.get(self.operator):
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msg = ("Rule '%(rule)s' contains operator '%(operator)s' "
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"which doesn't support data type '%(type)s' for "
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"attribute '%(attribute)s'")
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raise exception.ValidationError(msg % {"rule": self,
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"operator": self.operator,
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'type': attribute_info[1],
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'attribute': self.attribute})
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def generate_expression(self, target, multiple_values=False):
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special_attribute = self._attribute_special_field(target)
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if special_attribute:
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attribute_info = target.get(special_attribute)
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else:
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attribute_info = target.get(self.attribute)
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attributes = attribute_info[0].split('.')
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key_token = self.attribute.split('/')[-1]
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if attribute_info[1] == 'key_value_pair':
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filter_spec = []
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expression_key = {'field': attribute_info[2]['key_column'],
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'model': attribute_info[2]['model'],
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'value': key_token,
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'op': self.FILTER_OPERATOR_SPEC_MAPPING.get(self.operator)}
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expression_value = {'field': attribute_info[2]['value_column'],
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'model': attribute_info[2]['model'],
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'value': self.values if multiple_values else self.values[0],
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'op': self.FILTER_OPERATOR_SPEC_MAPPING.get(self.operator)}
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filter_spec.append(expression_key)
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filter_spec.append(expression_value)
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expression = {'and': filter_spec}
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else:
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expression = {'field': attributes[-1],
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'model': attribute_info[2],
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'value': self.values if multiple_values else self.values[0],
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'op': self.FILTER_OPERATOR_SPEC_MAPPING.get(self.operator)}
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return expression
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class AndFilter(BaseFilter):
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def __init__(self, filter_rule):
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self.filter_rules = filter_rule
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def __str__(self):
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"""Return a string representation of this filter."""
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return '(%s)' % ' and '.join(str(r) for r in self.filter_rules)
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def __call__(self, target):
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"""Run through this filter and maps it to the database model
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:returns
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A dict containing list of filter-specs required by
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sqlalchemy-filter.
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Example::
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filter=(eq,onboardingState,'onboarded');(eq,softwareImages/size, 10)
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Result would be:
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{
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'and': [
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{
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'field': 'onboarding_state', 'model': 'Foo',
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'value': "'onboarded'", 'op': '=='
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},
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{
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'field': 'size', 'model': 'Foo',
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'value': '10', 'op': '=='
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}
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]
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}
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"""
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filter_spec = []
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for filter_rule in self.filter_rules:
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result = filter_rule(target)
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filter_spec.append(result)
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return {'and': filter_spec}
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def add_filter_rule(self, filter_rule):
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"""Adds filter rule to be tested.
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Allows addition of another filter rule to the list of filter rules
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that will be tested.
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:returns: self
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:rtype: :class:`.AndFilter`
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"""
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self.filter_rules.append(filter_rule)
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return self
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def register(name, func=None):
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# Perform the actual decoration by registering the function or
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# class. Returns the function or class for compliance with the
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# decorator interface.
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def decorator(func):
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registered_filters[name] = func
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return func
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# If the function or class is given, do the registration
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if func:
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return decorator(func)
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return decorator
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@register('simple_filter_expr_one')
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class SimpleFilterExprOne(Filter):
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SUPPORTED_OPERATORS = SUPPORTED_OP_ONE
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def __call__(self, target):
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"""Run through this filter and maps it to the database model
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:returns
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A dict containing list of filter-specs required by
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sqlalchemy-filter.
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Example::
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operator=eq, attribute=onBoardingState, and value='onboarded', then
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it would be mapped to following expression.
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{
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'field': 'onboarding_state', -> Mapped to the version field
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'model': 'Foo', -> Mapped to database model
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'value': "onboarded", -> Value to be used for filtering
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records
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'op': '==', -> Operator for comparison
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},
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"""
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self._validate_operators()
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self._validate_attribute_name(target)
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self._validate_data_type(target)
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self._handle_values(target)
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return self.generate_expression(target, multiple_values=False)
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def _validate_operators(self):
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super(SimpleFilterExprOne, self)._validate_operators()
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if self.values and isinstance(self.values, list) and \
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len(self.values) > 1:
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msg = _("Rule '%(rule)s' contains operator '%(operator)s' "
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"which supports only one value, but multiple values "
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"'%(values)s' are provided")
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raise exception.ValidationError(msg % {"rule": self,
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"operator": self.operator,
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'values': ",".join(self.values)})
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@register('simple_filter_expr_multi')
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class SimpleFilterExprMulti(Filter):
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SUPPORTED_OPERATORS = SUPPORTED_OP_MULTI
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def __call__(self, target):
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"""Run through this filter and maps it to the database model
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This filter is exactly same as SimpleFilterExprOne, except
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it supports different operators like 'in'|'nin'|'cont'|'ncont'
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which contains more than one value in the list.
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:returns
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A dict containing list of filter-specs required by
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sqlalchemy-filter.
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Example::
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operator=in, attribute=softwareImages/size, and value=[10,20]',
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then it would be mapped to following expression.
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{
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'field': 'size', -> Mapped to the version field
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'model': 'Foo', -> Mapped to database model
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'value': [10,20], -> Value to be used for filtering
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records
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'op': 'in', -> Attribute equal to one of the values in the
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list ("in set" relationship)
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},
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"""
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self._validate_operators()
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self._validate_attribute_name(target)
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self._validate_data_type(target)
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self._handle_values(target)
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return self.generate_expression(target, multiple_values=True)
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@ -0,0 +1,259 @@
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# -*- coding: utf-8 -*-
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#
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# Copyright (c) 2020 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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import re
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import six
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from tacker.api.common import _filters
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from tacker.common import exceptions as exception
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def reducer(*tokens):
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"""Decorator for reduction methods.
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Arguments are a sequence of tokens, in order, which should trigger running
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this reduction method.
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"""
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def decorator(func):
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# Make sure we have a list of reducer sequences
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if not hasattr(func, 'reducers'):
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func.reducers = []
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# Add the tokens to the list of reducer sequences
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func.reducers.append(list(tokens))
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return func
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return decorator
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class ParseStateMeta(type):
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"""Metaclass for the :class:`.ParseState` class.
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Facilitates identifying reduction methods.
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"""
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def __new__(mcs, name, bases, cls_dict):
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"""Create the class.
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Injects the 'reducers' list, a list of tuples matching token sequences
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to the names of the corresponding reduction methods.
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"""
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reducers = []
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for key, value in cls_dict.items():
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if not hasattr(value, 'reducers'):
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continue
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for reduction in value.reducers:
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reducers.append((reduction, key))
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cls_dict['reducers'] = reducers
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return super(ParseStateMeta, mcs).__new__(mcs, name, bases, cls_dict)
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@six.add_metaclass(ParseStateMeta)
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class ParseState(object):
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"""Implement the core of parsing the policy language.
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Uses a greedy reduction algorithm to reduce a sequence of tokens into
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a single terminal, the value of which will be the root of the
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:class:`Filter` tree.
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.. note::
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Error reporting is rather lacking. The best we can get with this
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parser formulation is an overall "parse failed" error. Fortunately, the
|
||||
policy language is simple enough that this shouldn't be that big a
|
||||
problem.
|
||||
"""
|
||||
|
||||
def __init__(self):
|
||||
"""Initialize the ParseState."""
|
||||
|
||||
self.tokens = []
|
||||
self.values = []
|
||||
|
||||
def reduce(self):
|
||||
"""Perform a greedy reduction of the token stream.
|
||||
|
||||
If a reducer method matches, it will be executed, then the
|
||||
:meth:`reduce` method will be called recursively to search for any more
|
||||
possible reductions.
|
||||
"""
|
||||
|
||||
for reduction, methname in self.reducers:
|
||||
if (len(self.tokens) >= len(reduction) and
|
||||
self.tokens[-len(reduction):] == reduction):
|
||||
# Get the reduction method
|
||||
meth = getattr(self, methname)
|
||||
|
||||
# Reduce the token stream
|
||||
results = meth(*self.values[-len(reduction):])
|
||||
|
||||
# Update the tokens and values
|
||||
self.tokens[-len(reduction):] = [r[0] for r in results]
|
||||
self.values[-len(reduction):] = [r[1] for r in results]
|
||||
|
||||
# Check for any more reductions
|
||||
return self.reduce()
|
||||
|
||||
def shift(self, tok, value):
|
||||
"""Adds one more token to the state.
|
||||
|
||||
Calls :meth:`reduce`.
|
||||
"""
|
||||
|
||||
self.tokens.append(tok)
|
||||
self.values.append(value)
|
||||
|
||||
# Do a greedy reduce...
|
||||
self.reduce()
|
||||
|
||||
@property
|
||||
def result(self):
|
||||
"""Obtain the final result of the parse.
|
||||
|
||||
:raises ValueError: If the parse failed to reduce to a single result.
|
||||
"""
|
||||
|
||||
if len(self.values) != 1:
|
||||
raise ValueError('Could not parse rule')
|
||||
return self.values[0]
|
||||
|
||||
@reducer('(', 'filter', ')')
|
||||
@reducer('(', 'and_expr', ')')
|
||||
def _wrap_check(self, _p1, filter_data, _p2):
|
||||
"""Turn parenthesized expressions into a 'filter' token."""
|
||||
|
||||
return [('filter', filter_data)]
|
||||
|
||||
@reducer('filter', 'and', 'filter')
|
||||
def _make_and_expr(self, filter_data1, _and, filter_data2):
|
||||
"""Create an 'and_expr'.
|
||||
|
||||
Join two filters by the 'and' operator.
|
||||
"""
|
||||
return [('and_expr', _filters.AndFilter([filter_data1, filter_data2]))]
|
||||
|
||||
@reducer('and_expr', 'and', 'filter')
|
||||
def _extend_and_expr(self, and_expr, _and, filter_data):
|
||||
"""Extend an 'and_expr' by adding one more filter."""
|
||||
|
||||
return [('and_expr', and_expr.add_filter_rule(filter_data))]
|
||||
|
||||
|
||||
def _parse_filter(filter_rule):
|
||||
"""Parse a filter rule and return an appropriate Filter object."""
|
||||
|
||||
try:
|
||||
tokens = filter_rule.split(',')
|
||||
filter_type = None
|
||||
if len(tokens) >= 3:
|
||||
if tokens[0] in _filters.SUPPORTED_OP_ONE:
|
||||
filter_type = 'simple_filter_expr_one'
|
||||
elif tokens[0] in _filters.SUPPORTED_OP_MULTI:
|
||||
filter_type = 'simple_filter_expr_multi'
|
||||
except Exception:
|
||||
msg = 'Failed to understand filter %s' % filter_rule
|
||||
raise exception.ValidationError(msg)
|
||||
|
||||
if filter_type in _filters.registered_filters:
|
||||
return _filters.registered_filters[filter_type](tokens[0],
|
||||
tokens[1], tokens[2:])
|
||||
else:
|
||||
msg = 'Failed to understand filter %s' % filter_rule
|
||||
raise exception.ValidationError(msg)
|
||||
|
||||
|
||||
# Used for tokenizing the policy language
|
||||
_tokenize_re = re.compile(r'\;+')
|
||||
|
||||
|
||||
def _parse_tokenize(filter_rule):
|
||||
"""Tokenizer for the attribute filtering language.
|
||||
|
||||
Most of the single-character tokens are specified in the
|
||||
_tokenize_re; however, parentheses need to be handled specially,
|
||||
because they can appear inside a check string. Thankfully, those
|
||||
parentheses that appear inside a check string can never occur at
|
||||
the very beginning or end ("%(variable)s" is the correct syntax).
|
||||
"""
|
||||
main_tokens = _tokenize_re.split(filter_rule)
|
||||
index = 0
|
||||
for tok in main_tokens:
|
||||
# Skip empty tokens
|
||||
if not tok or tok.isspace():
|
||||
continue
|
||||
|
||||
# Handle leading parens on the token
|
||||
clean = tok.lstrip('(')
|
||||
for i in range(len(tok) - len(clean)):
|
||||
yield '(', '('
|
||||
|
||||
# If it was only parentheses, continue
|
||||
if not clean:
|
||||
continue
|
||||
else:
|
||||
tok = clean
|
||||
|
||||
# Handle trailing parens on the token
|
||||
clean = tok.rstrip(')')
|
||||
trail = len(tok) - len(clean)
|
||||
|
||||
# Yield the cleaned token
|
||||
lowered = clean.lower()
|
||||
if lowered in (';', 'and'):
|
||||
# Special tokens
|
||||
yield lowered, clean
|
||||
elif clean:
|
||||
# Not a special token, but not composed solely of ')'
|
||||
if len(tok) >= 2 and ((tok[0], tok[-1]) in
|
||||
[('"', '"'), ("'", "'")]):
|
||||
# It's a quoted string
|
||||
yield 'string', tok[1:-1]
|
||||
else:
|
||||
yield 'filter', _parse_filter(clean)
|
||||
|
||||
# Yield the trailing parens
|
||||
for i in range(trail):
|
||||
yield ')', ')'
|
||||
|
||||
if (index < len(main_tokens) - 1) and len(main_tokens) > 1:
|
||||
yield 'and', 'and'
|
||||
index += 1
|
||||
|
||||
|
||||
def parse_filter_rule(filter_rule, target=None):
|
||||
"""Parses filter query parameter to the tree.
|
||||
|
||||
Translates a filter written in the filter language into a tree of
|
||||
Filter objects.
|
||||
"""
|
||||
|
||||
# Parse the token stream
|
||||
state = ParseState()
|
||||
for tok, value in _parse_tokenize(filter_rule):
|
||||
state.shift(tok, value)
|
||||
|
||||
try:
|
||||
return state.result(target)
|
||||
except ValueError:
|
||||
err_msg = 'Failed to understand filter %s' % filter_rule
|
||||
raise exception.ValidationError(err_msg)
|
||||
Loading…
Reference in New Issue