kubectl源码分析之apply view-last-applied_kubectl apply yaml 源码-优快云博客

type ViewLastAppliedOptions struct {//viewlastapplied结构体
	FilenameOptions              resource.FilenameOptions
	Selector                     string
	LastAppliedConfigurationList []string
	OutputFormat                 string
	All                          bool
	Factory                      cmdutil.Factory

	genericclioptions.IOStreams
}

func NewViewLastAppliedOptions(ioStreams genericclioptions.IOStreams) *ViewLastAppliedOptions {//初始化结构体
	return &ViewLastAppliedOptions{
		OutputFormat: "yaml",

		IOStreams: ioStreams,
	}
}

//创建viewLastApplied命令
func NewCmdApplyViewLastApplied(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra.Command {
	options := NewViewLastAppliedOptions(ioStreams)//初始化结构体

	cmd := &cobra.Command{//创建cobra命令
		Use:                   "view-last-applied (TYPE [NAME | -l label] | TYPE/NAME | -f FILENAME)",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("View latest last-applied-configuration annotations of a resource/object"),
		Long:                  applyViewLastAppliedLong,
		Example:               applyViewLastAppliedExample,
		Run: func(cmd *cobra.Command, args []string) {
			cmdutil.CheckErr(options.Complete(cmd, f, args))//准备
			cmdutil.CheckErr(options.Validate(cmd))//校验
			cmdutil.CheckErr(options.RunApplyViewLastApplied(cmd))//运行
		},
	}

	cmd.Flags().StringVarP(&options.OutputFormat, "output", "o", options.OutputFormat, "Output format. Must be one of yaml|json")//输出选项
	cmd.Flags().StringVarP(&options.Selector, "selector", "l", options.Selector, "Selector (label query) to filter on, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2)")//selector选项
	cmd.Flags().BoolVar(&options.All, "all", options.All, "Select all resources in the namespace of the specified resource types")//all选项
	usage := "that contains the last-applied-configuration annotations"
	cmdutil.AddFilenameOptionFlags(cmd, &options.FilenameOptions, usage)//文件选项

	return cmd
}

//准备
func (o *ViewLastAppliedOptions) Complete(cmd *cobra.Command, f cmdutil.Factory, args []string) error {
	cmdNamespace, enforceNamespace, err := f.ToRawKubeConfigLoader().Namespace()//获取名称空间和enforce名称空间
	if err != nil {
		return err
	}

	r := f.NewBuilder().
		Unstructured().
		NamespaceParam(cmdNamespace).DefaultNamespace().
		FilenameParam(enforceNamespace, &o.FilenameOptions).
		ResourceTypeOrNameArgs(enforceNamespace, args...).
		SelectAllParam(o.All).
		LabelSelectorParam(o.Selector).
		Latest().
		Flatten().
		Do()//用builder构造result对象
	err = r.Err()
	if err != nil {
		return err
	}

	err = r.Visit(func(info *resource.Info, err error) error {visit result
		if err != nil {
			return err
		}

		configString, err := util.GetOriginalConfiguration(info.Object)//获取last-applied-configuration配置
		if err != nil {
			return err
		}
		if configString == nil {//配置为空返回错误
			return cmdutil.AddSourceToErr(fmt.Sprintf("no last-applied-configuration annotation found on resource: %s\n", info.Name), info.Source, err)
		}
		o.LastAppliedConfigurationList = append(o.LastAppliedConfigurationList, string(configString))//追加配置
		return nil
	})

	if err != nil {
		return err
	}

	return nil
}

// Validate checks ViewLastAppliedOptions for validity.
func (o *ViewLastAppliedOptions) Validate(cmd *cobra.Command) error {
	return nil
}

//运行
func (o *ViewLastAppliedOptions) RunApplyViewLastApplied(cmd *cobra.Command) error {
	for _, str := range o.LastAppliedConfigurationList {//遍历配置
		switch o.OutputFormat {
		case "json"://json格式输出
			jsonBuffer := &bytes.Buffer{}
			err := json.Indent(jsonBuffer, []byte(str), "", "  ")
			if err != nil {
				return err
			}
			fmt.Fprint(o.Out, string(jsonBuffer.Bytes()))
		case "yaml"://yaml格式输出
			yamlOutput, err := yaml.JSONToYAML([]byte(str))
			if err != nil {
				return err
			}
			fmt.Fprint(o.Out, string(yamlOutput))
		default:
			return cmdutil.UsageErrorf(
				cmd,
				"Unexpected -o output mode: %s, the flag 'output' must be one of yaml|json",
				o.OutputFormat)
		}
	}

	return nil
}