kubectl源码分析之explain
发布一个k8s部署视频：https://edu.csdn.net/course/detail/26967
课程内容：各种k8s部署方式。包括minikube部署，kubeadm部署，kubeasz部署，rancher部署，k3s部署。包括开发测试环境部署k8s，和生产环境部署k8s。
腾讯课堂连接地址https://ke.qq.com/course/478827?taid=4373109931462251&tuin=ba64518
第二个视频发布 https://edu.csdn.net/course/detail/27109
腾讯课堂连接地址https://ke.qq.com/course/484107?tuin=ba64518
介绍主要的k8s资源的使用配置和命令。包括configmap，pod，service，replicaset，namespace，deployment，daemonset，ingress，pv，pvc，sc，role，rolebinding，clusterrole，clusterrolebinding，secret，serviceaccount，statefulset，job，cronjob，podDisruptionbudget，podSecurityPolicy,networkPolicy,resourceQuota，limitrange，endpoint，event，conponentstatus，node，apiservice，controllerRevision等。
第三个视频发布：https://edu.csdn.net/course/detail/27574
详细介绍helm命令，学习helm chart语法，编写helm chart。深入分析各项目源码，学习编写helm插件
第四个课程发布：https://edu.csdn.net/course/detail/28488
本课程将详细介绍k8s所有命令，以及命令的go源码分析，学习知其然，知其所以然
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type ExplainOptions struct {//explain结构体
genericclioptions.IOStreams
CmdParent string
APIVersion string
Recursive bool
Mapper meta.RESTMapper
Schema openapi.Resources
}func NewExplainOptions(parent string, streams genericclioptions.IOStreams) *ExplainOptions {
return &ExplainOptions{//初始化explain结构体
IOStreams: streams,
CmdParent: parent,
}
}//创建explain命令
func NewCmdExplain(parent string, f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
o := NewExplainOptions(parent, streams)//初始化结构体
cmd := &cobra.Command{//创建cobra命令
Use: "explain RESOURCE",
DisableFlagsInUseLine: true,
Short: i18n.T("Documentation of resources"),
Long: explainLong + "\n\n" + cmdutil.SuggestAPIResources(parent),
Example: explainExamples,
Run: func(cmd *cobra.Command, args []string) {
cmdutil.CheckErr(o.Complete(f, cmd))//准备
cmdutil.CheckErr(o.Validate(args))//校验
cmdutil.CheckErr(o.Run(args))//运行
},
}
cmd.Flags().BoolVar(&o.Recursive, "recursive", o.Recursive, "Print the fields of fields (Currently only 1 level deep)")//recursive选项
cmd.Flags().StringVar(&o.APIVersion, "api-version", o.APIVersion, "Get different explanations for particular API version")//api-version选项
return cmd
}//准备方法
func (o *ExplainOptions) Complete(f cmdutil.Factory, cmd *cobra.Command) error {
var err error
o.Mapper, err = f.ToRESTMapper()//设置mapper
if err != nil {
return err
}
o.Schema, err = f.OpenAPISchema()//设置schema
if err != nil {
return err
}
return nil
}
//校验
func (o *ExplainOptions) Validate(args []string) error {
if len(args) == 0 {//参数不能为空
return fmt.Errorf("You must specify the type of resource to explain. %s\n", cmdutil.SuggestAPIResources(o.CmdParent))
}
if len(args) > 1 {//参数不能大于一个
return fmt.Errorf("We accept only this format: explain RESOURCE\n")
}
return nil
}//运行
func (o *ExplainOptions) Run(args []string) error {
recursive := o.Recursive
apiVersionString := o.APIVersion
// TODO: After we figured out the new syntax to separate group and resource, allow
// the users to use it in explain (kubectl explain ).
// Refer to issue #16039 for why we do this. Refer to PR #15808 that used "/" syntax.
inModel, fieldsPath, err := explain.SplitAndParseResourceRequest(args[0], o.Mapper)//用.分割resource和字段
if err != nil {
return err
}
// TODO: We should deduce the group for a resource by discovering the supported resources at server.
fullySpecifiedGVR, groupResource := schema.ParseResourceArg(inModel)//解析groupversionresource
gvk := schema.GroupVersionKind{}
if fullySpecifiedGVR != nil {
gvk, _ = o.Mapper.KindFor(*fullySpecifiedGVR)//从gvr获取gvk
}
if gvk.Empty() {//如果gvk为空，则获取版本为空的gvk
gvk, err = o.Mapper.KindFor(groupResource.WithVersion(""))
if err != nil {
return err
}
}
if len(apiVersionString) != 0 {//如果api-version不为空，则再次获取gvk
apiVersion, err := schema.ParseGroupVersion(apiVersionString)
if err != nil {
return err
}
gvk = apiVersion.WithKind(gvk.Kind)
}
schema := o.Schema.LookupResource(gvk)//获取schema
if schema == nil {
return fmt.Errorf("Couldn't find resource for %q", gvk)
}
return explain.PrintModelDescription(fieldsPath, o.Out, schema, gvk, recursive)//打印结果
}