kubectl源码分析之rollout restart

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 RestartOptions struct {//restart结构体
	PrintFlags *genericclioptions.PrintFlags
	ToPrinter  func(string) (printers.ResourcePrinter, error)

	Resources []string

	Builder          func() *resource.Builder
	Restarter        polymorphichelpers.ObjectRestarterFunc
	Namespace        string
	EnforceNamespace bool

	resource.FilenameOptions
	genericclioptions.IOStreams
}

func NewRolloutRestartOptions(streams genericclioptions.IOStreams) *RestartOptions {
	return &RestartOptions{//初始化结构体
		PrintFlags: genericclioptions.NewPrintFlags("restarted").WithTypeSetter(scheme.Scheme),
		IOStreams:  streams,
	}
}

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

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

	cmd := &cobra.Command{//创建cobra命令
		Use:                   "restart RESOURCE",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("Restart a resource"),
		Long:                  restartLong,
		Example:               restartExample,
		Run: func(cmd *cobra.Command, args []string) {
			cmdutil.CheckErr(o.Complete(f, cmd, args))//准备
			cmdutil.CheckErr(o.Validate())//校验
			cmdutil.CheckErr(o.RunRestart())//运行
		},
		ValidArgs: validArgs,//有效参数
	}

	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
}

//准备函数
func (o *RestartOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
	o.Resources = args//设置资源

	o.Restarter = polymorphichelpers.ObjectRestarterFn//设置Restarter函数

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

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

	o.Builder = f.NewBuilder//设置builder

	return nil
}

//校验
func (o *RestartOptions) Validate() error {
	if len(o.Resources) == 0 && cmdutil.IsFilenameSliceEmpty(o.Filenames, o.Kustomize) {//资源和文件至少有一个
		return fmt.Errorf("required resource not specified")
	}
	return nil
}

//运行
func (o RestartOptions) RunRestart() 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
	}

	allErrs := []error{}
	infos, err := r.Infos()//获取info对象
	if err != nil {
		// restore previous command behavior where
		// an error caused by retrieving infos due to
		// at least a single broken object did not result
		// in an immediate return, but rather an overall
		// aggregation of errors.
		allErrs = append(allErrs, err)
	}

	for _, patch := range set.CalculatePatches(infos, scheme.DefaultJSONEncoder(), set.PatchFn(o.Restarter)) {//计算info补丁，并遍历
		info := patch.Info

		if patch.Err != nil {//补丁有错误，append错误继续
			resourceString := info.Mapping.Resource.Resource
			if len(info.Mapping.Resource.Group) > 0 {
				resourceString = resourceString + "." + info.Mapping.Resource.Group
			}
			allErrs = append(allErrs, fmt.Errorf("error: %s %q %v", resourceString, info.Name, patch.Err))
			continue
		}

		if string(patch.Patch) == "{}" || len(patch.Patch) == 0 {//如果补丁为空，则append错误
			allErrs = append(allErrs, fmt.Errorf("failed to create patch for %v: empty patch", info.Name))
		}

		obj, err := resource.NewHelper(info.Client, info.Mapping).Patch(info.Namespace, info.Name, types.StrategicMergePatchType, patch.Patch, nil)//用helper应用补丁到服务端
		if err != nil {
			allErrs = append(allErrs, fmt.Errorf("failed to patch: %v", err))
			continue
		}

		info.Refresh(obj, true)//刷新obj对象
		printer, err := o.ToPrinter("restarted")//printflag转printer
		if err != nil {
			allErrs = append(allErrs, err)
			continue
		}
		if err = printer.PrintObj(info.Object, o.Out); err != nil {//打印结果
			allErrs = append(allErrs, err)
		}
	}

	return utilerrors.NewAggregate(allErrs)
}