Path validator API implementation to validate the gnmi path (sonic-net#76)

* Path validator API implementation to validate the gnmi path

Author: mbalachandar

translib/path/path_validator.go

@@ -0,0 +1,373 @@
+////////////////////////////////////////////////////////////////////////////////
+//                                                                            //
+//  Copyright 2021 Broadcom. The term Broadcom refers to Broadcom Inc. and/or //
+//  its subsidiaries.                                                         //
+//                                                                            //
+//  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 path
+
+import (
+	"reflect"
+	"strings"
+
+	"fmt"
+
+	"github.com/Azure/sonic-mgmt-common/translib/ocbinds"
+	"github.com/Azure/sonic-mgmt-common/translib/tlerr"
+	log "github.com/golang/glog"
+	"github.com/kylelemons/godebug/pretty"
+	"github.com/openconfig/gnmi/proto/gnmi"
+	"github.com/openconfig/goyang/pkg/yang"
+	"github.com/openconfig/ygot/util"
+	"github.com/openconfig/ygot/ygot"
+	"github.com/openconfig/ygot/ytypes"
+)
+
+type pathValidator struct {
+	gPath        *gnmi.Path
+	rootObj      *ocbinds.Device
+	sField       *reflect.StructField
+	sValIntf     interface{}
+	parentIntf   interface{}
+	opts         []PathValidatorOpt
+	parentSchema *yang.Entry
+	err          error
+}
+
+// NewPathValidator returns the PathValidator struct to validate the gnmi path and also add the missing module
+// prefix and key names and wild card values in the gnmi path based on the given PathValidatorOpt
+func NewPathValidator(opts ...PathValidatorOpt) *pathValidator {
+	return &pathValidator{rootObj: &(ocbinds.Device{}), opts: opts}
+}
+
+func (pv *pathValidator) init(gPath *gnmi.Path) {
+	gPath.Element = nil
+	pv.gPath = gPath
+	pv.sField = nil
+	pv.sValIntf = pv.rootObj
+	pv.parentIntf = pv.rootObj
+	pv.parentSchema = nil
+	pv.err = nil
+}
+
+// Validate the path and also add the module prefix / wild card keys in the gnmi path
+// based on the given PathValidatorOpt while creating the path validator.
+func (pv *pathValidator) Validate(gPath *gnmi.Path) error {
+	if pv == nil {
+		log.Warningf("error: pathValidator is nil")
+		return fmt.Errorf("pathValidator is nil")
+	}
+	if gPath == nil {
+		log.Warningf("error: gnmi path nil")
+		pv.err = fmt.Errorf("gnmi path nil")
+		return pv.err
+	}
+	if log.V(4) {
+		log.Info("Validate: path: ", gPath.Elem)
+	}
+	pv.init(gPath)
+	if pv.err = pv.validatePath(); pv.err != nil {
+		log.Warningf("error in validating the path: ", pv.err)
+	}
+	return pv.err
+}
+
+func (pv *pathValidator) getYangSchema() (*yang.Entry, error) {
+	sVal := reflect.ValueOf(pv.sValIntf)
+	if sVal.Elem().Type().Kind() == reflect.Struct {
+		objName := sVal.Elem().Type().Name()
+		if log.V(4) {
+			log.Info("getYangSchema: ygot object name: ", objName)
+		}
+		ygSchema := ocbinds.SchemaTree[objName]
+		if ygSchema == nil {
+			log.Warningf("error: ygot object name %v not found in the schema for the given path: %v", objName, pv.gPath)
+			return ygSchema, tlerr.NotFoundError{Format: fmt.Sprintf("invalid path %v", pv.gPath)}
+		}
+		if log.V(4) {
+			log.Infof("getYangSchema: found schema: %v for the field: %v", ygSchema.Name, *pv.sField)
+		}
+		return ygSchema, nil
+	}
+
+	ygSchema, err := util.ChildSchema(pv.parentSchema, *pv.sField)
+	if err != nil {
+		return nil, tlerr.NotFoundError{Format: fmt.Sprintf("invalid path %v; could not find schema for the field name: %v", pv.gPath, err)}
+	}
+	if ygSchema == nil {
+		return nil, tlerr.NotFoundError{Format: fmt.Sprintf("invalid path %v; could not find schema for the field name: %s", pv.gPath, pv.sField.Name)}
+	}
+	if log.V(4) {
+		log.Infof("getYangSchema:ChildSchema - found schema: %v for the field: %v", ygSchema.Name, *pv.sField)
+	}
+
+	return ygSchema, nil
+}
+
+func (pv *pathValidator) getStructField(nodeName string) *reflect.StructField {
+	var sField *reflect.StructField
+	sval := reflect.ValueOf(pv.sValIntf).Elem()
+	if sval.Kind() != reflect.Struct {
+		return nil
+	}
+	stype := sval.Type()
+	for i := 0; i < sval.NumField(); i++ {
+		fType := stype.Field(i)
+		if pathName, ok := fType.Tag.Lookup("path"); ok && pathName == nodeName {
+			if log.V(4) {
+				log.Infof("getStructField: found struct field: %v for the node name: %v ", fType, nodeName)
+			}
+			sField = &fType
+			break
+		}
+	}
+	return sField
+}
+
+func (pv *pathValidator) getModuleName() string {
+	modName, ok := pv.sField.Tag.Lookup("module")
+	if !ok {
+		modName = ""
+	}
+	return modName
+}
+
+func (pv *pathValidator) validatePath() error {
+	if log.V(4) {
+		log.Info("validatePath: path: ", pv.gPath.Elem)
+	}
+	isApnndModPrefix := pv.hasAppendModulePrefixOption()
+	isAddWcKey := pv.hasAddWildcardKeyOption()
+	isIgnoreKey := pv.hasIgnoreKeyValidationOption()
+	prevModName := ""
+	for idx, pathElem := range pv.gPath.Elem {
+		nodeName := pathElem.Name
+		modName := ""
+		names := strings.Split(pathElem.Name, ":")
+		if len(names) > 1 {
+			modName = names[0]
+			nodeName = names[1]
+			if log.V(4) {
+				log.Infof("validatePath: modName %v, and node name %v in the given path", modName, nodeName)
+			}
+		}
+
+		pv.sField = pv.getStructField(nodeName)
+		if pv.sField == nil {
+			return fmt.Errorf("Node %v not found in the given gnmi path %v: ", pathElem.Name, pv.gPath)
+		}
+
+		ygModName := pv.getModuleName()
+		if len(ygModName) == 0 {
+			return fmt.Errorf("Module name not found for the node %v in the given gnmi path %v: ", pathElem.Name, pv.gPath)
+		}
+
+		if log.V(4) {
+			log.Infof("validatePath: module name: %v found for the node %v: ", ygModName, pathElem.Name)
+		}
+
+		if len(modName) > 0 {
+			if ygModName != modName {
+				return fmt.Errorf("Invalid yang module prefix in the path node %v", pathElem.Name)
+			}
+		} else if isApnndModPrefix && (prevModName != ygModName || idx == 0) {
+			pv.gPath.Elem[idx].Name = ygModName + ":" + pathElem.Name
+			if log.V(4) {
+				log.Info("validatePath: appeneded the module prefix name for the path node: ", pv.gPath.Elem[idx])
+			}
+		}
+
+		pv.updateStructFieldVal()
+
+		ygSchema, err := pv.getYangSchema()
+		if err != nil {
+			return fmt.Errorf("yang schema not found for the node %v in the given path; %v", pathElem.Name, pv.gPath)
+		}
+
+		if !isIgnoreKey {
+			if ygSchema.IsList() {
+				if len(pathElem.Key) > 0 {
+					// validate the key names
+					keysMap := make(map[string]bool)
+					isWc := false
+					for kn, kv := range pathElem.Key {
+						keysMap[kn] = true
+						if kv == "*" && !isWc {
+							isWc = true
+						}
+					}
+					if log.V(4) {
+						log.Info("validatePath: validating the list key names for the node path: ", pathElem.Key)
+					}
+					if err := pv.validateListKeyNames(ygSchema, keysMap, idx); err != nil {
+						return err
+					}
+
+					if !isWc {
+						// validate the key values
+						gpath := &gnmi.Path{}
+						pElem := *pathElem
+						paths := strings.Split(pElem.Name, ":")
+						pElem.Name = paths[len(paths)-1]
+						gpath.Elem = append(gpath.Elem, &pElem)
+						if log.V(4) {
+							log.Info("validatePath: validating the list key values for the path: ", gpath)
+						}
+						if err := pv.validateListKeyValues(pv.parentSchema, gpath); err != nil {
+							return err
+						}
+					}
+				} else if isAddWcKey {
+					pv.gPath.Elem[idx].Key = make(map[string]string)
+					for _, kn := range strings.Fields(ygSchema.Key) {
+						pv.gPath.Elem[idx].Key[kn] = "*"
+					}
+					if log.V(4) {
+						log.Info("validatePath: added the key names and wild cards for the list node path: ", pv.gPath.Elem[idx])
+					}
+				}
+			}
+		}
+		prevModName = ygModName
+		pv.parentSchema = ygSchema
+	}
+	return nil
+}
+
+func (pv *pathValidator) validateListKeyNames(ygSchema *yang.Entry, keysMap map[string]bool, pathIdx int) error {
+	keyNames := strings.Fields(ygSchema.Key)
+	if len(keyNames) != len(keysMap) {
+		return tlerr.NotFoundError{Format: fmt.Sprintf("Invalid key names since number of keys present in the node: %v does not match with the given keys", ygSchema.Name)}
+	}
+	for _, kn := range keyNames {
+		if !keysMap[kn] {
+			return tlerr.NotFoundError{Format: fmt.Sprintf("Invalid key name: %v in the list node path: %v", pv.gPath.Elem[pathIdx].Key, pv.gPath.Elem[pathIdx].Name)}
+		}
+	}
+	return nil
+}
+
+func (pv *pathValidator) validateListKeyValues(schema *yang.Entry, gPath *gnmi.Path) error {
+	sVal := reflect.ValueOf(pv.parentIntf)
+	if log.V(4) {
+		log.Infof("validateListKeyValues: schema name: %v, and parent ygot type name: %v: ", schema.Name, sVal.Elem().Type().Name())
+	}
+	objIntf, _, err := ytypes.GetOrCreateNode(schema, pv.parentIntf, gPath)
+	if err != nil {
+		log.Warningf("error in GetOrCreateNode: %v", err)
+		return tlerr.NotFoundError{Format: fmt.Sprintf("Invalid key present in the node path: %v; error: %v", gPath, err)}
+	}
+	if log.V(4) {
+		log.Infof("validateListKeyValues: objIntf: %v", reflect.ValueOf(objIntf).Elem())
+	}
+
+	ygotStruct, ok := objIntf.(ygot.ValidatedGoStruct)
+	if !ok {
+		errStr := fmt.Sprintf("could not validate the gnmi path: %v since casting to ValidatedGoStruct fails", gPath)
+		log.Warningf(errStr)
+		return tlerr.NotFoundError{Format: fmt.Sprintf("Invalid key present in the node path: %v; error: %s", gPath, errStr)}
+	}
+	if log.V(4) {
+		pretty.Print(ygotStruct)
+	}
+	if err := ygotStruct.Validate(&ytypes.LeafrefOptions{IgnoreMissingData: true}); err != nil {
+		errStr := fmt.Sprintf("error in ValidatedGoStruct.Validate: %v", err)
+		log.Warningf(errStr)
+		return tlerr.NotFoundError{Format: fmt.Sprintf("Invalid key present in the node path: %v; error: %s", gPath, errStr)}
+	}
+	return nil
+}
+
+func (pv *pathValidator) updateStructFieldVal() {
+	if log.V(4) {
+		log.Infof("updateStructFieldVal: struct field: %v; struct field type: %v", pv.sField, pv.sField.Type)
+	}
+	var sVal reflect.Value
+
+	if util.IsTypeMap(pv.sField.Type) {
+		if log.V(4) {
+			log.Info("updateStructFieldVal: field type is map")
+		}
+		sVal = reflect.New(pv.sField.Type.Elem().Elem())
+	} else if pv.sField.Type.Kind() == reflect.Ptr {
+		if log.V(4) {
+			log.Info("updateStructFieldVal: field type is pointer")
+		}
+		sVal = reflect.New(pv.sField.Type.Elem())
+	} else {
+		sVal = reflect.New(pv.sField.Type)
+	}
+	if log.V(4) {
+		log.Info("updateStructFieldVal: sVal", sVal)
+	}
+	pv.parentIntf = pv.sValIntf
+	pv.sValIntf = sVal.Interface()
+}
+
+// PathValidatorOpt is an interface used for any option to be supplied
+type PathValidatorOpt interface {
+	IsPathValidatorOpt()
+}
+
+// AppendModulePrefix is an PathValidator option that indicates that
+// the missing module prefix in the given gnmi path will be added
+// during the path validation
+type AppendModulePrefix struct{}
+
+// IsPathValidatorOpt marks AppendModulePrefix as a valid PathValidatorOpt.
+func (*AppendModulePrefix) IsPathValidatorOpt() {}
+
+// AddWildcardKeys is an PathValidator option that indicates that
+// the missing wild card keys in the given gnmi path will be added
+// during the path validation
+type AddWildcardKeys struct{}
+
+// IsPathValidatorOpt marks AddWildcardKeys as a valid PathValidatorOpt.
+func (*AddWildcardKeys) IsPathValidatorOpt() {}
+
+// IgnoreKeyValidation is an PathValidator option to indicate the
+// validator to ignore the key validation in the given gnmi path during the path validation
+type IgnoreKeyValidation struct{}
+
+// IsPathValidatorOpt marks IgnoreKeyValidation as a valid PathValidatorOpt.
+func (*IgnoreKeyValidation) IsPathValidatorOpt() {}
+
+func (pv *pathValidator) hasIgnoreKeyValidationOption() bool {
+	for _, o := range pv.opts {
+		if _, ok := o.(*IgnoreKeyValidation); ok {
+			return true
+		}
+	}
+	return false
+}
+
+func (pv *pathValidator) hasAppendModulePrefixOption() bool {
+	for _, o := range pv.opts {
+		if _, ok := o.(*AppendModulePrefix); ok {
+			return true
+		}
+	}
+	return false
+}
+
+func (pv *pathValidator) hasAddWildcardKeyOption() bool {
+	for _, o := range pv.opts {
+		if _, ok := o.(*AddWildcardKeys); ok {
+			return true
+		}
+	}
+	return false
+}