mirror of https://github.com/k3s-io/k3s
137 lines
4.4 KiB
Go
137 lines
4.4 KiB
Go
/*
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Copyright 2018 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package genericclioptions
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import (
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"fmt"
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"io/ioutil"
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"sort"
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"strings"
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"github.com/spf13/cobra"
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"k8s.io/cli-runtime/pkg/printers"
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)
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// templates are logically optional for specifying a format.
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// this allows a user to specify a template format value
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// as --output=go-template=
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var templateFormats = map[string]bool{
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"template": true,
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"go-template": true,
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"go-template-file": true,
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"templatefile": true,
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}
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// GoTemplatePrintFlags provides default flags necessary for template printing.
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// Given the following flag values, a printer can be requested that knows
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// how to handle printing based on these values.
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type GoTemplatePrintFlags struct {
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// indicates if it is OK to ignore missing keys for rendering
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// an output template.
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AllowMissingKeys *bool
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TemplateArgument *string
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}
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// AllowedFormats returns slice of string of allowed GoTemplatePrint printing format
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func (f *GoTemplatePrintFlags) AllowedFormats() []string {
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formats := make([]string, 0, len(templateFormats))
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for format := range templateFormats {
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formats = append(formats, format)
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}
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sort.Strings(formats)
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return formats
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}
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// ToPrinter receives an templateFormat and returns a printer capable of
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// handling --template format printing.
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// Returns false if the specified templateFormat does not match a template format.
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func (f *GoTemplatePrintFlags) ToPrinter(templateFormat string) (printers.ResourcePrinter, error) {
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if (f.TemplateArgument == nil || len(*f.TemplateArgument) == 0) && len(templateFormat) == 0 {
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return nil, NoCompatiblePrinterError{Options: f, OutputFormat: &templateFormat}
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}
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templateValue := ""
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if f.TemplateArgument == nil || len(*f.TemplateArgument) == 0 {
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for format := range templateFormats {
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format = format + "="
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if strings.HasPrefix(templateFormat, format) {
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templateValue = templateFormat[len(format):]
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templateFormat = format[:len(format)-1]
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break
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}
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}
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} else {
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templateValue = *f.TemplateArgument
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}
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if _, supportedFormat := templateFormats[templateFormat]; !supportedFormat {
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return nil, NoCompatiblePrinterError{OutputFormat: &templateFormat, AllowedFormats: f.AllowedFormats()}
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}
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if len(templateValue) == 0 {
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return nil, fmt.Errorf("template format specified but no template given")
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}
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if templateFormat == "templatefile" || templateFormat == "go-template-file" {
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data, err := ioutil.ReadFile(templateValue)
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if err != nil {
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return nil, fmt.Errorf("error reading --template %s, %v", templateValue, err)
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}
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templateValue = string(data)
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}
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p, err := printers.NewGoTemplatePrinter([]byte(templateValue))
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if err != nil {
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return nil, fmt.Errorf("error parsing template %s, %v", templateValue, err)
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}
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allowMissingKeys := true
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if f.AllowMissingKeys != nil {
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allowMissingKeys = *f.AllowMissingKeys
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}
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p.AllowMissingKeys(allowMissingKeys)
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return p, nil
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}
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// AddFlags receives a *cobra.Command reference and binds
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// flags related to template printing to it
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func (f *GoTemplatePrintFlags) AddFlags(c *cobra.Command) {
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if f.TemplateArgument != nil {
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c.Flags().StringVar(f.TemplateArgument, "template", *f.TemplateArgument, "Template string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].")
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c.MarkFlagFilename("template")
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}
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if f.AllowMissingKeys != nil {
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c.Flags().BoolVar(f.AllowMissingKeys, "allow-missing-template-keys", *f.AllowMissingKeys, "If true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats.")
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}
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}
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// NewGoTemplatePrintFlags returns flags associated with
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// --template printing, with default values set.
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func NewGoTemplatePrintFlags() *GoTemplatePrintFlags {
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allowMissingKeysPtr := true
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templateValuePtr := ""
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return &GoTemplatePrintFlags{
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TemplateArgument: &templateValuePtr,
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AllowMissingKeys: &allowMissingKeysPtr,
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}
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}
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