set.go

/*
Copyright 2014 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.
*/

package config

import (
	"errors"
	"fmt"
	"io"
	"reflect"
	"strings"

	"github.com/spf13/cobra"
)

const (
	cannotHaveStepsAfterError                = "Cannot have steps after %v.  %v are remaining"
	additionStepRequiredUnlessUnsettingError = "Must have additional steps after %v unless you are unsetting it"
)

type setOptions struct {
	configAccess  ConfigAccess
	propertyName  string
	propertyValue string
}

const set_long = `Sets an individual value in a kubeconfig file
PROPERTY_NAME is a dot delimited name where each token represents either a attribute name or a map key.  Map keys may not contain dots.
PROPERTY_VALUE is the new value you wish to set.`

func NewCmdConfigSet(out io.Writer, configAccess ConfigAccess) *cobra.Command {
	options := &setOptions{configAccess: configAccess}

	cmd := &cobra.Command{
		Use:   "set PROPERTY_NAME PROPERTY_VALUE",
		Short: "Sets an individual value in a kubeconfig file",
		Long:  set_long,
		Run: func(cmd *cobra.Command, args []string) {
			if !options.complete(cmd) {
				return
			}

			err := options.run()
			if err != nil {
				fmt.Printf("%v\n", err)
			}
		},
	}

	return cmd
}

func (o setOptions) run() error {
	err := o.validate()
	if err != nil {
		return err
	}

	config, err := o.configAccess.GetStartingConfig()
	if err != nil {
		return err
	}
	steps, err := newNavigationSteps(o.propertyName)
	if err != nil {
		return err
	}
	err = modifyConfig(reflect.ValueOf(config), steps, o.propertyValue, false)
	if err != nil {
		return err
	}

	if err := ModifyConfig(o.configAccess, *config); err != nil {
		return err
	}

	return nil
}

func (o *setOptions) complete(cmd *cobra.Command) bool {
	endingArgs := cmd.Flags().Args()
	if len(endingArgs) != 2 {
		cmd.Help()
		return false
	}

	o.propertyValue = endingArgs[1]
	o.propertyName = endingArgs[0]
	return true
}

func (o setOptions) validate() error {
	if len(o.propertyValue) == 0 {
		return errors.New("You cannot use set to unset a property")
	}

	if len(o.propertyName) == 0 {
		return errors.New("You must specify a property")
	}

	return nil
}

func modifyConfig(curr reflect.Value, steps *navigationSteps, propertyValue string, unset bool) error {
	currStep := steps.pop()

	actualCurrValue := curr
	if curr.Kind() == reflect.Ptr {
		actualCurrValue = curr.Elem()
	}

	switch actualCurrValue.Kind() {
	case reflect.Map:
		if !steps.moreStepsRemaining() && !unset {
			return fmt.Errorf("Can't set a map to a value: %v", actualCurrValue)
		}

		mapKey := reflect.ValueOf(currStep.stepValue)
		mapValueType := curr.Type().Elem().Elem()

		if !steps.moreStepsRemaining() && unset {
			actualCurrValue.SetMapIndex(mapKey, reflect.Value{})
			return nil
		}

		currMapValue := actualCurrValue.MapIndex(mapKey)

		needToSetNewMapValue := currMapValue.Kind() == reflect.Invalid
		if needToSetNewMapValue {
			currMapValue = reflect.New(mapValueType).Elem()
			actualCurrValue.SetMapIndex(mapKey, currMapValue)
		}

		// our maps do not hold pointers to structs, they hold the structs themselves.  This means that MapIndex returns the struct itself
		// That in turn means that they have kinds of type.Struct, which is not a settable type.  Because of this, we need to make new struct of that type
		// copy all the data from the old value into the new value, then take the .addr of the new value to modify it in the next recursion.
		// clear as mud
		modifiableMapValue := reflect.New(currMapValue.Type()).Elem()
		modifiableMapValue.Set(currMapValue)

		if modifiableMapValue.Kind() == reflect.Struct {
			modifiableMapValue = modifiableMapValue.Addr()
		}
		err := modifyConfig(modifiableMapValue, steps, propertyValue, unset)
		if err != nil {
			return err
		}

		actualCurrValue.SetMapIndex(mapKey, reflect.Indirect(modifiableMapValue))
		return nil

	case reflect.String:
		if steps.moreStepsRemaining() {
			return fmt.Errorf("Can't have more steps after a string. %v", steps)
		}
		actualCurrValue.SetString(propertyValue)
		return nil

	case reflect.Bool:
		if steps.moreStepsRemaining() {
			return fmt.Errorf("Can't have more steps after a bool. %v", steps)
		}
		boolValue, err := toBool(propertyValue)
		if err != nil {
			return err
		}
		actualCurrValue.SetBool(boolValue)
		return nil

	case reflect.Struct:
		for fieldIndex := 0; fieldIndex < actualCurrValue.NumField(); fieldIndex++ {
			currFieldValue := actualCurrValue.Field(fieldIndex)
			currFieldType := actualCurrValue.Type().Field(fieldIndex)
			currYamlTag := currFieldType.Tag.Get("json")
			currFieldTypeYamlName := strings.Split(currYamlTag, ",")[0]

			if currFieldTypeYamlName == currStep.stepValue {
				thisMapHasNoValue := (currFieldValue.Kind() == reflect.Map && currFieldValue.IsNil())

				if thisMapHasNoValue {
					newValue := reflect.MakeMap(currFieldValue.Type())
					currFieldValue.Set(newValue)

					if !steps.moreStepsRemaining() && unset {
						return nil
					}
				}

				if !steps.moreStepsRemaining() && unset {
					// if we're supposed to unset the value or if the value is a map that doesn't exist, create a new value and overwrite
					newValue := reflect.New(currFieldValue.Type()).Elem()
					currFieldValue.Set(newValue)
					return nil
				}

				return modifyConfig(currFieldValue.Addr(), steps, propertyValue, unset)
			}
		}

		return fmt.Errorf("Unable to locate path %#v under %v", currStep, actualCurrValue)

	}

	return fmt.Errorf("Unrecognized type: %v", actualCurrValue)
}