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type UndoOptions struct {//undo结构体
PrintFlags *genericclioptions.PrintFlags
ToPrinter func(string) (printers.ResourcePrinter, error)
Builder func() *resource.Builder
ToRevision int64
DryRun bool
Resources []string
Namespace string
EnforceNamespace bool
RESTClientGetter genericclioptions.RESTClientGetter
resource.FilenameOptions
genericclioptions.IOStreams
}
func NewRolloutUndoOptions(streams genericclioptions.IOStreams) *UndoOptions {
return &UndoOptions{//初始化结构体
PrintFlags: genericclioptions.NewPrintFlags("rolled back").WithTypeSetter(scheme.Scheme),
IOStreams: streams,
ToRevision: int64(0),
}
}
//创建undo命令
func NewCmdRolloutUndo(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
o := NewRolloutUndoOptions(streams)//初始化结构体
validArgs := []string{"deployment", "daemonset", "statefulset"}
cmd := &cobra.Command{//创建cobra命令
Use: "undo (TYPE NAME | TYPE/NAME) [flags]",
DisableFlagsInUseLine: true,
Short: i18n.T("Undo a previous rollout"),
Long: undoLong,
Example: undoExample,
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.RunUndo())//运行
},
ValidArgs: validArgs,//有效参数
}
cmd.Flags().Int64Var(&o.ToRevision, "to-revision", o.ToRevision, "The revision to rollback to. Default to 0 (last revision).")//to-revision选项
usage := "identifying the resource to get from a server."
cmdutil.AddFilenameOptionFlags(cmd, &o.FilenameOptions, usage)//文件选项
cmdutil.AddDryRunFlag(cmd)//干跑选项
o.PrintFlags.AddFlags(cmd)//打印选项
return cmd
}
//准备函数
func (o *UndoOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
o.Resources = args//设置资源
o.DryRun = cmdutil.GetDryRunFlag(cmd)//设置干跑
var err error
if o.Namespace, o.EnforceNamespace, err = f.ToRawKubeConfigLoader().Namespace(); err != nil {//设置Namespace和EnforceNamespace
return err
}
o.ToPrinter = func(operation string) (printers.ResourcePrinter, error) {//printflag转printer函数
o.PrintFlags.NamePrintFlags.Operation = operation
if o.DryRun {
o.PrintFlags.Complete("%s (dry run)")
}
return o.PrintFlags.ToPrinter()
}
o.RESTClientGetter = f//设置RestClientGetter
o.Builder = f.NewBuilder//设置Builder
return err
}
//校验函数
func (o *UndoOptions) 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 *UndoOptions) RunUndo() 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
}
err := r.Visit(func(info *resource.Info, err error) error {//visit Result
if err != nil {
return err
}
rollbacker, err := polymorphichelpers.RollbackerFn(o.RESTClientGetter, info.ResourceMapping())//获取回滚器
if err != nil {
return err
}
result, err := rollbacker.Rollback(info.Object, nil, o.ToRevision, o.DryRun)//执行回滚
if err != nil {
return err
}
printer, err := o.ToPrinter(result)//print flag转printer
if err != nil {
return err
}
return printer.PrintObj(info.Object, o.Out)//打印结果
})
return err
}
//执行回滚
func (r *DeploymentRollbacker) Rollback(obj runtime.Object, updatedAnnotations map[string]string, toRevision int64, dryRun bool) (string, error) {
if toRevision < 0 {//回滚范本不能小于0
return "", revisionNotFoundErr(toRevision)
}
accessor, err := meta.Accessor(obj)//访问对象
if err != nil {
return "", fmt.Errorf("failed to create accessor for kind %v: %s", obj.GetObjectKind(), err.Error())
}
name := accessor.GetName()//获取obj名称
namespace := accessor.GetNamespace()//获取obj namespace
// TODO: Fix this after kubectl has been removed from core. It is not possible to convert the runtime.Object
// to the external appsv1 Deployment without round-tripping through an internal version of Deployment. We're
// currently getting rid of all internal versions of resources. So we specifically request the appsv1 version
// here. This follows the same pattern as for DaemonSet and StatefulSet.
deployment, err := r.c.AppsV1().Deployments(namespace).Get(name, metav1.GetOptions{})//获取deployment
if err != nil {
return "", fmt.Errorf("failed to retrieve Deployment %s: %v", name, err)
}
rsForRevision, err := deploymentRevision(deployment, r.c, toRevision)//获取对应版本的rs
if err != nil {
return "", err
}
if dryRun {//如果是干盘返回
return printTemplate(&rsForRevision.Spec.Template)
}
if deployment.Spec.Paused {//如果deploy已经暂停，返回错误
return "", fmt.Errorf("you cannot rollback a paused deployment; resume it first with 'kubectl rollout resume deployment/%s' and try again", name)
}
// Skip if the revision already matches current Deployment
if equalIgnoreHash(&rsForRevision.Spec.Template, &deployment.Spec.Template) {//如果要更新的rs的template和现在的deploy的template一样则，返回提示template一样
return fmt.Sprintf("%s (current template already matches revision %d)", rollbackSkipped, toRevision), nil
}
// remove hash label before patching back into the deployment
delete(rsForRevision.Spec.Template.Labels, appsv1.DefaultDeploymentUniqueLabelKey)//删除rs的pod-template-hash标签
// compute deployment annotations
annotations := map[string]string{}//设置annotation
for k := range annotationsToSkip {
if v, ok := deployment.Annotations[k]; ok {
annotations[k] = v
}
}
for k, v := range rsForRevision.Annotations {
if !annotationsToSkip[k] {
annotations[k] = v
}
}
// make patch to restore
patchType, patch, err := getDeploymentPatch(&rsForRevision.Spec.Template, annotations)//获取patch
if err != nil {
return "", fmt.Errorf("failed restoring revision %d: %v", toRevision, err)
}
// Restore revision
if _, err = r.c.AppsV1().Deployments(namespace).Patch(name, patchType, patch); err != nil {//应用patch到服务端
return "", fmt.Errorf("failed restoring revision %d: %v", toRevision, err)
}
return rollbackSuccess, nil//返回成功
}