versioned.go

/*
Copyright 2017 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 printers

import (
	"fmt"
	"io"

	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
)

// VersionedPrinter takes runtime objects and ensures they are converted to a given API version
// prior to being passed to a nested printer.
type VersionedPrinter struct {
	printer   ResourcePrinter
	converter runtime.ObjectConvertor
	versions  []schema.GroupVersion
}

// NewVersionedPrinter wraps a printer to convert objects to a known API version prior to printing.
func NewVersionedPrinter(printer ResourcePrinter, converter runtime.ObjectConvertor, versions ...schema.GroupVersion) ResourcePrinter {
	return &VersionedPrinter{
		printer:   printer,
		converter: converter,
		versions:  versions,
	}
}

func (p *VersionedPrinter) AfterPrint(w io.Writer, res string) error {
	return nil
}

// PrintObj implements ResourcePrinter
func (p *VersionedPrinter) PrintObj(obj runtime.Object, w io.Writer) error {
	if len(p.versions) == 0 {
		return fmt.Errorf("no version specified, object cannot be converted")
	}
	converted, err := p.converter.ConvertToVersion(obj, schema.GroupVersions(p.versions))
	if err != nil {
		return err
	}
	return p.printer.PrintObj(converted, w)
}

// TODO: implement HandledResources()
func (p *VersionedPrinter) HandledResources() []string {
	return []string{}
}

func (p *VersionedPrinter) IsGeneric() bool {
	return p.printer.IsGeneric()
}