kubectl源码分析之rollout history

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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​​

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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
  })
}