kubectl源码分析之rollout pause

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

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

  resource.FilenameOptions
  genericclioptions.IOStreams
}      

//创建pause命令
func NewCmdRolloutPause(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
  o := &PauseOptions{//初始化结构体
    PrintFlags: genericclioptions.NewPrintFlags("paused").WithTypeSetter(scheme.Scheme),
    IOStreams:  streams,
  }

  validArgs := []string{"deployment"}

  cmd := &cobra.Command{//创建cobra命令
    Use:                   "pause RESOURCE",
    DisableFlagsInUseLine: true,
    Short:                 i18n.T("Mark the provided resource as paused"),
    Long:                  pauseLong,
    Example:               pauseExample,
    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.RunPause())//运行
    },
    ValidArgs: validArgs,//有效参数
  }

  o.PrintFlags.AddFlags(cmd)//设置打印选项

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

//准备方法
func (o *PauseOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
  o.Pauser = polymorphichelpers.ObjectPauserFn//设置Pauser函数

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

  o.Resources = args//设置resources
  o.Builder = f.NewBuilder//设置Builder

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

  return nil
}      

//校验函数
func (o *PauseOptions) 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")
  }
  return nil
}      

//运行
func (o *PauseOptions) RunPause() 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info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.Pauser)) {//计算patches，然后遍历
    info := patch.Info

    if patch.Err != nil {//patch有error，处理error
      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 {//patch为空
      printer, err := o.ToPrinter("already paused")//printflag转printer
      if err != nil {
        allErrs = append(allErrs, err)
        continue
      }
      if err = printer.PrintObj(info.Object, o.Out); err != nil {//打印对象
        allErrs = append(allErrs, err)
      }
      continue
    }

    obj, err := resource.NewHelper(info.Client, info.Mapping).Patch(info.Namespace, info.Name, types.StrategicMergePatchType, patch.Patch, nil)//应用patch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
    printer, err := o.ToPrinter("paused")// print flag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)
}