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helm/expandybird/expansion/schema_validation_utils.py

125 lines
4.1 KiB

######################################################################
# Copyright 2015 The Kubernetes Authors 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.
######################################################################
"""Helper functions for Schema Validation."""
import jsonschema
DEFAULT = "default"
PROPERTIES = "properties"
REF = "$ref"
REQUIRED = "required"
def OnlyValidateProperties(validator_class):
"""Takes a validator and makes it process only the 'properties' top level.
Args:
validator_class: A class to add a new validator to
Returns:
A validator_class that will validate properties against things
under the top level "properties" field
"""
def PropertiesValidator(unused_validator, inputs, instance, schema):
if inputs is None:
inputs = {}
for error in validator_class(schema).iter_errors(instance, inputs):
yield error
# This makes sure the only keyword jsonschema will validate is 'properties'
new_validators = ClearValidatorMap(validator_class.VALIDATORS)
new_validators.update({PROPERTIES: PropertiesValidator})
return jsonschema.validators.extend(
validator_class, new_validators)
def ExtendWithDefault(validator_class):
"""Takes a validator and makes it set default values on properties.
Args:
validator_class: A class to add our overridden validators to
Returns:
A validator_class that will set default values and ignore required fields
"""
def SetDefaultsInProperties(validator, properties, instance, unused_schema):
if properties is None:
properties = {}
SetDefaults(validator, properties, instance)
return jsonschema.validators.extend(
validator_class, {PROPERTIES: SetDefaultsInProperties,
REQUIRED: IgnoreKeyword})
def SetDefaults(validator, properties, instance):
"""Populate the default values of properties.
Args:
validator: A generator that validates the "properties" keyword
properties: User properties on which to set defaults
instance: Piece of user schema containing "properties"
"""
if not properties:
return
for dm_property, subschema in properties.iteritems():
# If the property already has a value, we don't need it's default
if dm_property in instance:
return
# The ordering of these conditions assumes that '$ref' blocks override
# all other schema info, which is what the jsonschema library assumes.
# If the subschema has a reference,
# see if that reference defines a 'default' value
if REF in subschema:
out = ResolveReferencedDefault(validator, subschema[REF])
instance.setdefault(dm_property, out)
# Otherwise, see if the subschema has a 'default' value
elif DEFAULT in subschema:
instance.setdefault(dm_property, subschema[DEFAULT])
def ResolveReferencedDefault(validator, ref):
"""Resolves a reference, and returns any default value it defines.
Args:
validator: A generator the validates the "$ref" keyword
ref: The target of the "$ref" keyword
Returns:
The value of the 'default' field found in the referenced schema, or None
"""
with validator.resolver.resolving(ref) as resolved:
if DEFAULT in resolved:
return resolved[DEFAULT]
def ClearValidatorMap(validators):
"""Remaps all JsonSchema validators to make them do nothing."""
ignore_validators = {}
for keyword in validators:
ignore_validators.update({keyword: IgnoreKeyword})
return ignore_validators
def IgnoreKeyword(
unused_validator, unused_required, unused_instance, unused_schema):
"""Validator for JsonSchema that does nothing."""
pass