sigs.k8s.io/cluster-api@v1.6.3/internal/topology/variables/clusterclass_variable_validation.go

/*
Copyright 2021 The Kubernetes Authors.

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.
*/

package variables

import (
	"context"
	"fmt"
	"strings"

	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions"
	structuralschema "k8s.io/apiextensions-apiserver/pkg/apiserver/schema"
	structuraldefaulting "k8s.io/apiextensions-apiserver/pkg/apiserver/schema/defaulting"
	"k8s.io/apiextensions-apiserver/pkg/apiserver/validation"
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/apimachinery/pkg/util/validation/field"

	clusterv1 "sigs.k8s.io/cluster-api/api/v1beta1"
)

const (
	// builtinsName is the name of the builtin variable.
	builtinsName = "builtin"
)

// ValidateClusterClassVariables validates clusterClassVariable.
func ValidateClusterClassVariables(ctx context.Context, clusterClassVariables []clusterv1.ClusterClassVariable, fldPath *field.Path) field.ErrorList {
	var allErrs field.ErrorList

	allErrs = append(allErrs, validateClusterClassVariableNamesUnique(clusterClassVariables, fldPath)...)

	for i := range clusterClassVariables {
		allErrs = append(allErrs, validateClusterClassVariable(ctx, &clusterClassVariables[i], fldPath.Index(i))...)
	}

	return allErrs
}

// validateClusterClassVariableNamesUnique validates that ClusterClass variable names are unique.
func validateClusterClassVariableNamesUnique(clusterClassVariables []clusterv1.ClusterClassVariable, pathPrefix *field.Path) field.ErrorList {
	var allErrs field.ErrorList

	variableNames := sets.Set[string]{}
	for i, clusterClassVariable := range clusterClassVariables {
		if variableNames.Has(clusterClassVariable.Name) {
			allErrs = append(allErrs,
				field.Invalid(
					pathPrefix.Index(i).Child("name"),
					clusterClassVariable.Name,
					fmt.Sprintf("variable name must be unique. Variable with name %q is defined more than once", clusterClassVariable.Name),
				),
			)
		}
		variableNames.Insert(clusterClassVariable.Name)
	}

	return allErrs
}

// validateClusterClassVariable validates a ClusterClassVariable.
func validateClusterClassVariable(ctx context.Context, variable *clusterv1.ClusterClassVariable, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	// Validate variable name.
	allErrs = append(allErrs, validateClusterClassVariableName(variable.Name, fldPath.Child("name"))...)

	// Validate schema.
	allErrs = append(allErrs, validateRootSchema(ctx, variable, fldPath.Child("schema", "openAPIV3Schema"))...)

	return allErrs
}

// validateClusterClassVariableName validates a variable name.
func validateClusterClassVariableName(variableName string, fldPath *field.Path) field.ErrorList {
	allErrs := field.ErrorList{}

	if variableName == "" {
		allErrs = append(allErrs, field.Required(fldPath, "variable name must be defined"))
	}

	if variableName == builtinsName {
		allErrs = append(allErrs, field.Invalid(fldPath, variableName, fmt.Sprintf("%q is a reserved variable name", builtinsName)))
	}
	if strings.Contains(variableName, ".") {
		allErrs = append(allErrs, field.Invalid(fldPath, variableName, "variable name cannot contain \".\"")) // TODO: consider if to restrict variable names to RFC 1123
	}

	return allErrs
}

var validVariableTypes = sets.Set[string]{}.Insert("object", "array", "string", "number", "integer", "boolean")

// validateRootSchema validates the schema.
func validateRootSchema(ctx context.Context, clusterClassVariable *clusterv1.ClusterClassVariable, fldPath *field.Path) field.ErrorList {
	var allErrs field.ErrorList

	apiExtensionsSchema, allErrs := convertToAPIExtensionsJSONSchemaProps(&clusterClassVariable.Schema.OpenAPIV3Schema, field.NewPath("schema"))
	if len(allErrs) > 0 {
		return field.ErrorList{field.InternalError(fldPath,
			fmt.Errorf("failed to convert schema definition for variable %q; ClusterClass should be checked: %v", clusterClassVariable.Name, allErrs))} // TODO: consider if to add ClusterClass name
	}

	// Validate structural schema.
	// Note: structural schema only allows `type: object` on the root level, so we wrap the schema with:
	// type: object
	// properties:
	//   variableSchema: <variable-schema>
	wrappedSchema := &apiextensions.JSONSchemaProps{
		Type: "object",
		Properties: map[string]apiextensions.JSONSchemaProps{
			"variableSchema": *apiExtensionsSchema,
		},
	}

	// Get the structural schema for the variable.
	ss, err := structuralschema.NewStructural(wrappedSchema)
	if err != nil {
		return append(allErrs, field.Invalid(fldPath.Child("schema"), "", err.Error()))
	}

	// Validate the schema.
	if validationErrors := structuralschema.ValidateStructural(fldPath.Child("schema"), ss); len(validationErrors) > 0 {
		return append(allErrs, validationErrors...)
	}

	// Validate defaults in the structural schema.
	validationErrors, err := structuraldefaulting.ValidateDefaults(ctx, fldPath.Child("schema"), ss, true, true)
	if err != nil {
		return append(allErrs, field.Invalid(fldPath.Child("schema"), "", err.Error()))
	}
	if len(validationErrors) > 0 {
		return append(allErrs, validationErrors...)
	}

	// If the structural schema is valid, ensure a schema validator can be constructed.
	if _, _, err := validation.NewSchemaValidator(apiExtensionsSchema); err != nil {
		return append(allErrs, field.Invalid(fldPath, "", fmt.Sprintf("failed to build validator: %v", err)))
	}

	allErrs = append(allErrs, validateSchema(apiExtensionsSchema, fldPath)...)
	return allErrs
}

func validateSchema(schema *apiextensions.JSONSchemaProps, fldPath *field.Path) field.ErrorList {
	var allErrs field.ErrorList

	// Validate that type is one of the validVariableTypes.
	switch {
	case schema.Type == "":
		return field.ErrorList{field.Required(fldPath.Child("type"), "type cannot be empty")}
	case !validVariableTypes.Has(schema.Type):
		return field.ErrorList{field.NotSupported(fldPath.Child("type"), schema.Type, sets.List(validVariableTypes))}
	}

	// If the structural schema is valid, ensure a schema validator can be constructed.
	validator, _, err := validation.NewSchemaValidator(schema)
	if err != nil {
		return append(allErrs, field.Invalid(fldPath, "", fmt.Sprintf("failed to build validator: %v", err)))
	}

	if schema.Example != nil {
		if errs := validation.ValidateCustomResource(fldPath, *schema.Example, validator); len(errs) > 0 {
			allErrs = append(allErrs, field.Invalid(fldPath.Child("example"), schema.Example, fmt.Sprintf("invalid value in example: %v", errs)))
		}
	}

	for i, enum := range schema.Enum {
		if enum != nil {
			if errs := validation.ValidateCustomResource(fldPath, enum, validator); len(errs) > 0 {
				allErrs = append(allErrs, field.Invalid(fldPath.Child("enum").Index(i), enum, fmt.Sprintf("invalid value in enum: %v", errs)))
			}
		}
	}

	if schema.AdditionalProperties != nil {
		if len(schema.Properties) > 0 {
			allErrs = append(allErrs, field.Forbidden(fldPath.Child("additionalProperties"), "additionalProperties and properties are mutual exclusive"))
		}
		allErrs = append(allErrs, validateSchema(schema.AdditionalProperties.Schema, fldPath.Child("additionalProperties"))...)
	}

	for propertyName, propertySchema := range schema.Properties {
		p := propertySchema
		allErrs = append(allErrs, validateSchema(&p, fldPath.Child("properties").Key(propertyName))...)
	}

	if schema.Items != nil {
		allErrs = append(allErrs, validateSchema(schema.Items.Schema, fldPath.Child("items"))...)
	}

	return allErrs
}