kubectl源码分析之set image

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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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type SetImageOptions struct {set image结构体
	resource.FilenameOptions

	PrintFlags  *genericclioptions.PrintFlags
	RecordFlags *genericclioptions.RecordFlags

	Infos        []*resource.Info
	Selector     string
	DryRun       bool
	All          bool
	Output       string
	Local        bool
	ResolveImage ImageResolver

	PrintObj printers.ResourcePrinterFunc
	Recorder genericclioptions.Recorder

	UpdatePodSpecForObject polymorphichelpers.UpdatePodSpecForObjectFunc
	Resources              []string
	ContainerImages        map[string]string

	genericclioptions.IOStreams
}

func NewImageOptions(streams genericclioptions.IOStreams) *SetImageOptions {
	return &SetImageOptions{//初始化结构体
		PrintFlags:  genericclioptions.NewPrintFlags("image updated").WithTypeSetter(scheme.Scheme),
		RecordFlags: genericclioptions.NewRecordFlags(),

		Recorder: genericclioptions.NoopRecorder{},

		IOStreams: streams,
	}
}

//创建set image 命令
func NewCmdImage(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
	o := NewImageOptions(streams)//初始化结构体

	cmd := &cobra.Command{//创建cobra命令
		Use:                   "image (-f FILENAME | TYPE NAME) CONTAINER_NAME_1=CONTAINER_IMAGE_1 ... CONTAINER_NAME_N=CONTAINER_IMAGE_N",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("Update image of a pod template"),
		Long:                  imageLong,
		Example:               imageExample,
		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.Run())//运行
		},
	}

	o.PrintFlags.AddFlags(cmd)//设置打印选项
	o.RecordFlags.AddFlags(cmd)//设置record选项

	usage := "identifying the resource to get from a server."
	cmdutil.AddFilenameOptionFlags(cmd, &o.FilenameOptions, usage)//设置文件选项
	cmd.Flags().BoolVar(&o.All, "all", o.All, "Select all resources, including uninitialized ones, in the namespace of the specified resource types")//设置all选项
	cmd.Flags().StringVarP(&o.Selector, "selector", "l", o.Selector, "Selector (label query) to filter on, not including uninitialized ones, supports '=', '==', and '!='.(e.g. -l key1=value1,key2=value2)")//设置selector选项
	cmd.Flags().BoolVar(&o.Local, "local", o.Local, "If true, set image will NOT contact api-server but run locally.")//设置local选项
	cmdutil.AddDryRunFlag(cmd)//设置dryrun选项
	cmdutil.AddIncludeUninitializedFlag(cmd)
	return cmd
}

//准备运行
func (o *SetImageOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
	var err error

	o.RecordFlags.Complete(cmd)//complete record
	o.Recorder, err = o.RecordFlags.ToRecorder()//record flag转recorder
	if err != nil {
		return err
	}

	o.UpdatePodSpecForObject = polymorphichelpers.UpdatePodSpecForObjectFn//设置updatePodSepc函数
	o.DryRun = cmdutil.GetDryRunFlag(cmd)//设置干跑
	o.Output = cmdutil.GetFlagString(cmd, "output")//设置output
	o.ResolveImage = resolveImageFunc

	if o.DryRun {
		o.PrintFlags.Complete("%s (dry run)")
	}
	printer, err := o.PrintFlags.ToPrinter()//print flag转printer
	if err != nil {
		return err
	}

	o.PrintObj = printer.PrintObj//设置printObj函数

	cmdNamespace, enforceNamespace, err := f.ToRawKubeConfigLoader().Namespace()//获取namespace和enforceNamespace
	if err != nil {
		return err
	}

	o.Resources, o.ContainerImages, err = getResourcesAndImages(args)//设置resource和containerImage
	if err != nil {
		return err
	}

	builder := f.NewBuilder().
		WithScheme(scheme.Scheme, scheme.Scheme.PrioritizedVersionsAllGroups()...).
		LocalParam(o.Local).
		ContinueOnError().
		NamespaceParam(cmdNamespace).DefaultNamespace().
		FilenameParam(enforceNamespace, &o.FilenameOptions).
		Flatten()//构造info对象

	if !o.Local {
		builder.LabelSelectorParam(o.Selector).
			ResourceTypeOrNameArgs(o.All, o.Resources...).
			Latest()
	} else {
		// if a --local flag was provided, and a resource was specified in the form
		// <resource>/<name>, fail immediately as --local cannot query the api server
		// for the specified resource.
		if len(o.Resources) > 0 {
			return resource.LocalResourceError
		}
	}

	o.Infos, err = builder.Do().Infos()//设置info对象
	if err != nil {
		return err
	}

	return nil
}

//校验函数
func (o *SetImageOptions) Validate() error {
	errors := []error{}
	if o.All && len(o.Selector) > 0 {//all和selector不能同时指定
		errors = append(errors, fmt.Errorf("cannot set --all and --selector at the same time"))
	}
	if len(o.Resources) < 1 && cmdutil.IsFilenameSliceEmpty(o.Filenames, o.Kustomize) {//必须指定资源或文件
		errors = append(errors, fmt.Errorf("one or more resources must be specified as <resource> <name> or <resource>/<name>"))
	}
	if len(o.ContainerImages) < 1 {//容器image不能为空
		errors = append(errors, fmt.Errorf("at least one image update is required"))
	} else if len(o.ContainerImages) > 1 && hasWildcardKey(o.ContainerImages) {//带*的容器image只能有一个
		errors = append(errors, fmt.Errorf("all containers are already specified by *, but saw more than one container_name=container_image pairs"))
	}
	return utilerrors.NewAggregate(errors)
}

//运行命令
func (o *SetImageOptions) Run() error {
	allErrs := []error{}

	patches := CalculatePatches(o.Infos, scheme.DefaultJSONEncoder(), func(obj runtime.Object) ([]byte, error) {//构造patch
		_, err := o.UpdatePodSpecForObject(obj, func(spec *v1.PodSpec) error {//更新对象的ped spec
			for name, image := range o.ContainerImages {//遍历containerImage
				resolvedImageName, err := o.ResolveImage(image)
				if err != nil {
					allErrs = append(allErrs, fmt.Errorf("error: unable to resolve image %q for container %q: %v", image, name, err))
					if name == "*" {
						break
					}
					continue
				}

				initContainerFound := setImage(spec.InitContainers, name, resolvedImageName)//更新init container
				containerFound := setImage(spec.Containers, name, resolvedImageName)//更新container
				if !containerFound && !initContainerFound {
					allErrs = append(allErrs, fmt.Errorf("error: unable to find container named %q", name))
				}
			}
			return nil
		})
		if err != nil {
			return nil, err
		}
		// record this change (for rollout history)
		if err := o.Recorder.Record(obj); err != nil {//判断是否创建change-cause注解
			klog.V(4).Infof("error recording current command: %v", err)
		}

		return runtime.Encode(scheme.DefaultJSONEncoder(), obj)//编码对象
	})

	for _, patch := range patches {//遍历patch
		info := patch.Info
		if patch.Err != nil {
			name := info.ObjectName()
			allErrs = append(allErrs, fmt.Errorf("error: %s %v\n", name, patch.Err))
			continue
		}

		// no changes
		if string(patch.Patch) == "{}" || len(patch.Patch) == 0 {
			continue
		}

		if o.Local || o.DryRun {//如果是local或干跑，打印对象
			if err := o.PrintObj(info.Object, o.Out); err != nil {
				allErrs = append(allErrs, err)
			}
			continue
		}

		// patch the change
		actual, err := resource.NewHelper(info.Client, info.Mapping).Patch(info.Namespace, info.Name, types.StrategicMergePatchType, patch.Patch, nil)//应用patch
		if err != nil {
			allErrs = append(allErrs, fmt.Errorf("failed to patch image update to pod template: %v", err))
			continue
		}

		if err := o.PrintObj(actual, o.Out); err != nil {//打印对象
			allErrs = append(allErrs, err)
		}
	}
	return utilerrors.NewAggregate(allErrs)
}