kubectl源码分析之rollout history

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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//创建rollout命令
func NewCmdRollout(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
	cmd := &cobra.Command{//创建cobra命令
		Use:                   "rollout SUBCOMMAND",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("Manage the rollout of a resource"),
		Long:                  rolloutLong,
		Example:               rolloutExample,
		Run:                   cmdutil.DefaultSubCommandRun(streams.Out),
	}
	// subcommands
	cmd.AddCommand(NewCmdRolloutHistory(f, streams))//添加history命令
	cmd.AddCommand(NewCmdRolloutPause(f, streams))//添加pause命令
	cmd.AddCommand(NewCmdRolloutResume(f, streams))//添加resume命令
	cmd.AddCommand(NewCmdRolloutUndo(f, streams))//添加undo命令
	cmd.AddCommand(NewCmdRolloutStatus(f, streams))//添加status命令
	cmd.AddCommand(NewCmdRolloutRestart(f, streams))//添加restart命令

	return cmd
}

type RolloutHistoryOptions struct {//history结构体
	PrintFlags *genericclioptions.PrintFlags
	ToPrinter  func(string) (printers.ResourcePrinter, error)

	Revision int64

	Builder          func() *resource.Builder
	Resources        []string
	Namespace        string
	EnforceNamespace bool

	HistoryViewer    polymorphichelpers.HistoryViewerFunc
	RESTClientGetter genericclioptions.RESTClientGetter

	resource.FilenameOptions
	genericclioptions.IOStreams
}

// NewRolloutHistoryOptions returns an initialized RolloutHistoryOptions instance
func NewRolloutHistoryOptions(streams genericclioptions.IOStreams) *RolloutHistoryOptions {
	return &RolloutHistoryOptions{//初始化history结构体
		PrintFlags: genericclioptions.NewPrintFlags("").WithTypeSetter(scheme.Scheme),
		IOStreams:  streams,
	}
}

//创建history命令
func NewCmdRolloutHistory(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
	o := NewRolloutHistoryOptions(streams)//初始化结构体

	validArgs := []string{"deployment", "daemonset", "statefulset"}

	cmd := &cobra.Command{//创建cobra命令
		Use:                   "history (TYPE NAME | TYPE/NAME) [flags]",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("View rollout history"),
		Long:                  historyLong,
		Example:               historyExample,
		Run: func(cmd *cobra.Command, args []string) {
			cmdutil.CheckErr(o.Complete(f, cmd, args))//准备运行
			cmdutil.CheckErr(o.Validate())//校验
			cmdutil.CheckErr(o.Run())//运行
		},
		ValidArgs: validArgs,
	}

	cmd.Flags().Int64Var(&o.Revision, "revision", o.Revision, "See the details, including podTemplate of the revision specified")//创建revision选项

	usage := "identifying the resource to get from a server."
	cmdutil.AddFilenameOptionFlags(cmd, &o.FilenameOptions, usage)//文件选项

	o.PrintFlags.AddFlags(cmd)//打印选项

	return cmd
}

//准备
func (o *RolloutHistoryOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
	o.Resources = args//设置resources

	var err error
	if o.Namespace, o.EnforceNamespace, err = f.ToRawKubeConfigLoader().Namespace(); err != nil {//获取namespace和enforceNamespace
		return err
	}

	o.ToPrinter = func(operation string) (printers.ResourcePrinter, error) {//printflag转printer函数
		o.PrintFlags.NamePrintFlags.Operation = operation
		return o.PrintFlags.ToPrinter()
	}

	o.HistoryViewer = polymorphichelpers.HistoryViewerFn//historyViewer函数
	o.RESTClientGetter = f//RestClientGerrter
	o.Builder = f.NewBuilder//设置builder

	return nil
}

//校验
func (o *RolloutHistoryOptions) Validate() error {
	if len(o.Resources) == 0 && cmdutil.IsFilenameSliceEmpty(o.Filenames, o.Kustomize) {//资源和文件至少指定一个
		return fmt.Errorf("required resource not specified")
	}
	if o.Revision < 0 {//revision必须大于0
		return fmt.Errorf("revision must be a positive integer: %v", o.Revision)
	}

	return nil
}

//运行
func (o *RolloutHistoryOptions) Run() error {

	r := o.Builder().
		WithScheme(scheme.Scheme, scheme.Scheme.PrioritizedVersionsAllGroups()...).
		NamespaceParam(o.Namespace).DefaultNamespace().
		FilenameParam(o.EnforceNamespace, &o.FilenameOptions).
		ResourceTypeOrNameArgs(true, o.Resources...).
		ContinueOnError().
		Latest().
		Flatten().
		Do()//构造result对象
	if err := r.Err(); err != nil {
		return err
	}

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

		mapping := info.ResourceMapping()
		historyViewer, err := o.HistoryViewer(o.RESTClientGetter, mapping)//获取HistoryViewer
		if err != nil {
			return err
		}
		historyInfo, err := historyViewer.ViewHistory(info.Namespace, info.Name, o.Revision)//获取历史信息
		if err != nil {
			return err
		}

		withRevision := ""
		if o.Revision > 0 {
			withRevision = fmt.Sprintf("with revision #%d", o.Revision)
		}

		printer, err := o.ToPrinter(fmt.Sprintf("%s\n%s", withRevision, historyInfo))//获取printer
		if err != nil {
			return err
		}

		return printer.PrintObj(info.Object, o.Out)//打印结果
	})
}