kubectl源码分析之api-versions

 欢迎关注我的公众号：

 目前刚开始写一个月，一共写了18篇原创文章，文章目录如下：

istio多集群探秘，部署了50次多集群后我得出的结论

istio多集群链路追踪，附实操视频

istio防故障利器，你知道几个,istio新手不要读，太难！

istio业务权限控制，原来可以这么玩

istio实现非侵入压缩，微服务之间如何实现压缩

不懂envoyfilter也敢说精通istio系列-http-rbac-不要只会用AuthorizationPolicy配置权限

不懂envoyfilter也敢说精通istio系列-02-http-corsFilter-不要只会vs

不懂envoyfilter也敢说精通istio系列-03-http-csrf filter-再也不用再代码里写csrf逻辑了

不懂envoyfilter也敢说精通istio系列http-jwt_authn-不要只会RequestAuthorization

不懂envoyfilter也敢说精通istio系列-05-fault-filter-故障注入不止是vs

不懂envoyfilter也敢说精通istio系列-06-http-match-配置路由不只是vs

不懂envoyfilter也敢说精通istio系列-07-负载均衡配置不止是dr

不懂envoyfilter也敢说精通istio系列-08-连接池和断路器

不懂envoyfilter也敢说精通istio系列-09-http-route filter

不懂envoyfilter也敢说精通istio系列-network filter-redis proxy

不懂envoyfilter也敢说精通istio系列-network filter-HttpConnectionManager

不懂envoyfilter也敢说精通istio系列-ratelimit-istio ratelimit完全手册

 

————————————————

type APIVersionsOptions struct {//apiversions结构体
	discoveryClient discovery.CachedDiscoveryInterface

	genericclioptions.IOStreams
}

func NewAPIVersionsOptions(ioStreams genericclioptions.IOStreams) *APIVersionsOptions {
	return &APIVersionsOptions{//初始化结构体
		IOStreams: ioStreams,
	}
}

//创建apiversions命令
func NewCmdAPIVersions(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra.Command {
	o := NewAPIVersionsOptions(ioStreams)//初始化结构体
	cmd := &cobra.Command{
		Use:     "api-versions",
		Short:   "Print the supported API versions on the server, in the form of \"group/version\"",
		Long:    "Print the supported API versions on the server, in the form of \"group/version\"",
		Example: apiversionsExample,
		Run: func(cmd *cobra.Command, args []string) {
			cmdutil.CheckErr(o.Complete(f, cmd, args))//准备
			cmdutil.CheckErr(o.RunAPIVersions())//运行
		},
	}
	return cmd
}

//准备
func (o *APIVersionsOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
	if len(args) != 0 {//参数必须是0个
		return cmdutil.UsageErrorf(cmd, "unexpected arguments: %v", args)
	}
	var err error
	o.discoveryClient, err = f.ToDiscoveryClient()//设置discoveryClient
	if err != nil {
		return err
	}
	return nil
}

//运行
func (o *APIVersionsOptions) RunAPIVersions() error {
	// Always request fresh data from the server
	o.discoveryClient.Invalidate()//使缓存失效

	groupList, err := o.discoveryClient.ServerGroups()//获取apiGroupList
	if err != nil {
		return fmt.Errorf("couldn't get available api versions from server: %v", err)
	}
	apiVersions := metav1.ExtractGroupVersions(groupList)//从apiGroupList抽取apiVersions
	sort.Strings(apiVersions)//排序
	for _, v := range apiVersions {//遍历apiversions
		fmt.Fprintln(o.Out, v)//打印
	}
	return nil
}