openapi.go

// Copyright 2017 The kubecfg 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 utils

import (
	"fmt"
	"reflect"
	"regexp"

	"github.com/emicklei/go-restful/swagger"
	log "github.com/sirupsen/logrus"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/client-go/discovery"
)

// This is unashamedly copied from
// k8s.io/kubernetes/pkg/api/validation/schema.go, and rebased onto
// client-go/apimachinery object types

// InvalidTypeError is returned when an invalid type is encountered
type InvalidTypeError struct {
	ExpectedKind reflect.Kind
	ObservedKind reflect.Kind
	FieldName    string
}

func (i *InvalidTypeError) Error() string {
	return fmt.Sprintf("expected type %s, for field %s, got %s", i.ExpectedKind.String(), i.FieldName, i.ObservedKind.String())
}

// NewInvalidTypeError creates an InvalidTypeError object
func NewInvalidTypeError(expected reflect.Kind, observed reflect.Kind, fieldName string) error {
	return &InvalidTypeError{expected, observed, fieldName}
}

// TypeNotFoundError is returned when specified type
// can not found in schema
type TypeNotFoundError string

func (tnfe TypeNotFoundError) Error() string {
	return fmt.Sprintf("couldn't find type: %s", string(tnfe))
}

// SwaggerSchema represents an OpenAPI/Swagger schema
type SwaggerSchema struct {
	api      *swagger.ApiDeclaration
	delegate discovery.SwaggerSchemaInterface
}

// NewSwaggerSchemaFor returns the SwaggerSchema object ready to validate objects of given GroupVersion
func NewSwaggerSchemaFor(delegate discovery.SwaggerSchemaInterface, gv schema.GroupVersion) (*SwaggerSchema, error) {
	log.Debugf("Fetching schema for %v", gv)
	swagger, err := delegate.SwaggerSchema(gv)
	if err != nil {
		return nil, err
	}
	return &SwaggerSchema{api: swagger, delegate: delegate}, nil
}

// validateList unpacks a list and validate every item in the list.
// It return nil if every item is ok.
// Otherwise it return an error list contain errors of every item.
func (s *SwaggerSchema) validateList(obj map[string]interface{}) []error {
	items, exists := obj["items"]
	if !exists {
		return []error{fmt.Errorf("no items field in %#v", obj)}
	}
	return s.validateItems(items)
}

func (s *SwaggerSchema) validateItems(items interface{}) []error {
	allErrs := []error{}
	itemList, ok := items.([]interface{})
	if !ok {
		return append(allErrs, fmt.Errorf("items isn't a slice"))
	}
	for i, item := range itemList {
		fields, ok := item.(map[string]interface{})
		if !ok {
			allErrs = append(allErrs, fmt.Errorf("items[%d] isn't a map[string]interface{}", i))
			continue
		}
		groupVersion := fields["apiVersion"]
		if groupVersion == nil {
			allErrs = append(allErrs, fmt.Errorf("items[%d].apiVersion not set", i))
			continue
		}
		itemVersion, ok := groupVersion.(string)
		if !ok {
			allErrs = append(allErrs, fmt.Errorf("items[%d].apiVersion isn't string type", i))
			continue
		}
		if len(itemVersion) == 0 {
			allErrs = append(allErrs, fmt.Errorf("items[%d].apiVersion is empty", i))
		}
		kind := fields["kind"]
		if kind == nil {
			allErrs = append(allErrs, fmt.Errorf("items[%d].kind not set", i))
			continue
		}
		itemKind, ok := kind.(string)
		if !ok {
			allErrs = append(allErrs, fmt.Errorf("items[%d].kind isn't string type", i))
			continue
		}
		if len(itemKind) == 0 {
			allErrs = append(allErrs, fmt.Errorf("items[%d].kind is empty", i))
		}
		gv, err := schema.ParseGroupVersion(itemVersion)
		if err != nil {
			allErrs = append(allErrs, fmt.Errorf("items[%d].apiVersion is invalid", i))
		}
		errs := s.ValidateObject(item, "", gv.Version+"."+itemKind)
		if len(errs) >= 1 {
			allErrs = append(allErrs, errs...)
		}
	}

	return allErrs
}

// Validate is the primary entrypoint into this class
func (s *SwaggerSchema) Validate(obj *unstructured.Unstructured) []error {
	if obj.IsList() {
		return s.validateList(obj.UnstructuredContent())
	}
	gvk := obj.GroupVersionKind()
	return s.ValidateObject(obj.UnstructuredContent(), "", fmt.Sprintf("%s.%s", gvk.Version, gvk.Kind))
}

// ValidateObject validates a JSON object against the schema
func (s *SwaggerSchema) ValidateObject(obj interface{}, fieldName, typeName string) []error {
	allErrs := []error{}
	models := s.api.Models
	model, ok := models.At(typeName)

	// Verify the api version matches.  This is required for nested types with differing api versions because
	// s.api only has schema for 1 api version (the parent object type's version).
	// e.g. an extensions/v1beta1 Template embedding a /v1 Service requires the schema for the extensions/v1beta1
	// api to delegate to the schema for the /v1 api.
	// Only do this for !ok objects so that cross ApiVersion vendored types take precedence.
	if !ok && s.delegate != nil {
		fields, mapOk := obj.(map[string]interface{})
		if !mapOk {
			return append(allErrs, fmt.Errorf("field %s for %s: expected object of type map[string]interface{}, but the actual type is %T", fieldName, typeName, obj))
		}
		if delegated, errs := s.delegateIfDifferentApiVersion(&unstructured.Unstructured{Object: fields}); delegated {
			allErrs = append(allErrs, errs...)
			return allErrs
		}
	}

	if !ok {
		return append(allErrs, TypeNotFoundError(typeName))
	}
	properties := model.Properties
	if len(properties.List) == 0 {
		// The object does not have any sub-fields.
		return nil
	}
	fields, ok := obj.(map[string]interface{})
	if !ok {
		return append(allErrs, fmt.Errorf("field %s for %s: expected object of type map[string]interface{}, but the actual type is %T", fieldName, typeName, obj))
	}
	if len(fieldName) > 0 {
		fieldName = fieldName + "."
	}
	// handle required fields
	for _, requiredKey := range model.Required {
		if _, ok := fields[requiredKey]; !ok {
			allErrs = append(allErrs, fmt.Errorf("field %s%s for %s is required", fieldName, requiredKey, typeName))
		}
	}
	for key, value := range fields {
		details, ok := properties.At(key)

		// Special case for runtime.RawExtension and runtime.Objects because they always fail to validate
		// This is because the actual values will be of some sub-type (e.g. Deployment) not the expected
		// super-type (RawExtension)
		if s.isGenericArray(details) {
			errs := s.validateItems(value)
			if len(errs) > 0 {
				allErrs = append(allErrs, errs...)
			}
			continue
		}
		if !ok {
			allErrs = append(allErrs, fmt.Errorf("found invalid field %s for %s", key, typeName))
			continue
		}
		if details.Type == nil && details.Ref == nil {
			allErrs = append(allErrs, fmt.Errorf("could not find the type of %s%s from object %v", fieldName, key, details))
		}
		var fieldType string
		if details.Type != nil {
			fieldType = *details.Type
		} else {
			fieldType = *details.Ref
		}
		if value == nil {
			log.Debugf("Skipping nil field: %s%s", fieldName, key)
			continue
		}
		errs := s.validateField(value, fieldName+key, fieldType, &details)
		if len(errs) > 0 {
			allErrs = append(allErrs, errs...)
		}
	}
	return allErrs
}

// delegateIfDifferentApiVersion delegates the validation of an object if its ApiGroup does not match the
// current SwaggerSchema.
// First return value is true if the validation was delegated (by a different ApiGroup SwaggerSchema)
// Second return value is the result of the delegated validation if performed.
func (s *SwaggerSchema) delegateIfDifferentApiVersion(obj *unstructured.Unstructured) (bool, []error) {
	// Never delegate objects in the same ApiVersion or we will get infinite recursion
	if !s.isDifferentApiVersion(obj) {
		return false, nil
	}

	// Delegate validation of this object to the correct SwaggerSchema for its ApiGroup
	newSchema, err := NewSwaggerSchemaFor(s.delegate, obj.GroupVersionKind().GroupVersion())
	if err != nil {
		return true, []error{err}
	}
	return true, newSchema.Validate(obj)
}

// isDifferentApiVersion Returns true if obj lives in a different ApiVersion than the SwaggerSchema does.
// The SwaggerSchema will not be able to process objects in different ApiVersions unless they are vendored.
func (s *SwaggerSchema) isDifferentApiVersion(obj *unstructured.Unstructured) bool {
	groupVersion := obj.GetAPIVersion()
	return len(groupVersion) > 0 && s.api.ApiVersion != groupVersion
}

// isGenericArray Returns true if p is an array of generic Objects - either RawExtension or Object.
func (s *SwaggerSchema) isGenericArray(p swagger.ModelProperty) bool {
	return p.DataTypeFields.Type != nil &&
		*p.DataTypeFields.Type == "array" &&
		p.Items != nil &&
		p.Items.Ref != nil &&
		(*p.Items.Ref == "runtime.RawExtension" || *p.Items.Ref == "runtime.Object")
}

// This matches type name in the swagger spec, such as "v1.Binding".
var versionRegexp = regexp.MustCompile(`^(v.+|unversioned)\..*`)

func (s *SwaggerSchema) validateField(value interface{}, fieldName, fieldType string, fieldDetails *swagger.ModelProperty) []error {
	allErrs := []error{}
	if reflect.TypeOf(value) == nil {
		return append(allErrs, fmt.Errorf("unexpected nil value for field %v", fieldName))
	}
	// TODO: caesarxuchao: because we have multiple group/versions and objects
	// may reference objects in other group, the commented out way of checking
	// if a filedType is a type defined by us is outdated. We use a hacky way
	// for now.
	// TODO: the type name in the swagger spec is something like "v1.Binding",
	// and the "v1" is generated from the package name, not the groupVersion of
	// the type. We need to fix go-restful to embed the group name in the type
	// name, otherwise we couldn't handle identically named types in different
	// groups correctly.
	if versionRegexp.MatchString(fieldType) {
		// if strings.HasPrefix(fieldType, apiVersion) {
		return s.ValidateObject(value, fieldName, fieldType)
	}
	switch fieldType {
	case "string":
		// Be loose about what we accept for 'string' since we use IntOrString in a couple of places
		_, isString := value.(string)
		_, isNumber := value.(float64)
		_, isInteger := value.(int)
		_, isInteger64 := value.(int64)
		if !isString && !isNumber && !isInteger && !isInteger64 {
			return append(allErrs, NewInvalidTypeError(reflect.String, reflect.TypeOf(value).Kind(), fieldName))
		}
	case "array":
		arr, ok := value.([]interface{})
		if !ok {
			return append(allErrs, NewInvalidTypeError(reflect.Array, reflect.TypeOf(value).Kind(), fieldName))
		}
		var arrType string
		if fieldDetails.Items.Ref == nil && fieldDetails.Items.Type == nil {
			return append(allErrs, NewInvalidTypeError(reflect.Array, reflect.TypeOf(value).Kind(), fieldName))
		}
		if fieldDetails.Items.Ref != nil {
			arrType = *fieldDetails.Items.Ref
		} else {
			arrType = *fieldDetails.Items.Type
		}
		for ix := range arr {
			errs := s.validateField(arr[ix], fmt.Sprintf("%s[%d]", fieldName, ix), arrType, nil)
			if len(errs) > 0 {
				allErrs = append(allErrs, errs...)
			}
		}
	case "uint64":
	case "int64":
	case "integer":
		_, isNumber := value.(float64)
		_, isInteger := value.(int)
		_, isInteger64 := value.(int64)
		if !isNumber && !isInteger && !isInteger64 {
			return append(allErrs, NewInvalidTypeError(reflect.Int, reflect.TypeOf(value).Kind(), fieldName))
		}
	case "float64":
		if _, ok := value.(float64); !ok {
			return append(allErrs, NewInvalidTypeError(reflect.Float64, reflect.TypeOf(value).Kind(), fieldName))
		}
	case "boolean":
		if _, ok := value.(bool); !ok {
			return append(allErrs, NewInvalidTypeError(reflect.Bool, reflect.TypeOf(value).Kind(), fieldName))
		}
	// API servers before release 1.3 produce swagger spec with `type: "any"` as the fallback type, while newer servers produce spec with `type: "object"`.
	// We have both here so that kubectl can work with both old and new api servers.
	case "object":
	case "any":
	default:
		return append(allErrs, fmt.Errorf("unexpected type: %v", fieldType))
	}
	return allErrs
}