kubectl源码分析之expose

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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

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不懂envoyfilter也敢说精通istio系列-ratelimit-istio ratelimit完全手册

 

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type ExposeServiceOptions struct {//expose结构体
	FilenameOptions resource.FilenameOptions
	RecordFlags     *genericclioptions.RecordFlags
	PrintFlags      *genericclioptions.PrintFlags
	PrintObj        printers.ResourcePrinterFunc

	DryRun           bool
	EnforceNamespace bool

	Generators                func(string) map[string]generate.Generator
	CanBeExposed              polymorphichelpers.CanBeExposedFunc
	MapBasedSelectorForObject func(runtime.Object) (string, error)
	PortsForObject            polymorphichelpers.PortsForObjectFunc
	ProtocolsForObject        func(runtime.Object) (map[string]string, error)

	Namespace string
	Mapper    meta.RESTMapper

	DynamicClient dynamic.Interface
	Builder       *resource.Builder

	Recorder genericclioptions.Recorder
	genericclioptions.IOStreams
}
unc NewExposeServiceOptions(ioStreams genericclioptions.IOStreams) *ExposeServiceOptions {
	return &ExposeServiceOptions{//创建expose结构体
		RecordFlags: genericclioptions.NewRecordFlags(),
		PrintFlags:  genericclioptions.NewPrintFlags("exposed").WithTypeSetter(scheme.Scheme),

		Recorder:  genericclioptions.NoopRecorder{},
		IOStreams: ioStreams,
	}
}
//创建expose命令
func NewCmdExposeService(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
	o := NewExposeServiceOptions(streams)//初始化结构体

	validArgs := []string{}
	resources := regexp.MustCompile(`\s*,`).Split(exposeResources, -1)
	for _, r := range resources {
		validArgs = append(validArgs, strings.Fields(r)[0])//设置有效参数
	}

	cmd := &cobra.Command{//创建cobra命令
		Use:                   "expose (-f FILENAME | TYPE NAME) [--port=port] [--protocol=TCP|UDP|SCTP] [--target-port=number-or-name] [--name=name] [--external-ip=external-ip-of-service] [--type=type]",
		DisableFlagsInUseLine: true,
		Short:                 i18n.T("Take a replication controller, service, deployment or pod and expose it as a new Kubernetes Service"),
		Long:                  exposeLong,
		Example:               exposeExample,
		Run: func(cmd *cobra.Command, args []string) {
			cmdutil.CheckErr(o.Complete(f, cmd))//准备运行
			cmdutil.CheckErr(o.RunExpose(cmd, args))运行
		},
		ValidArgs: validArgs,
	}

	o.RecordFlags.AddFlags(cmd)//设置record选项
	o.PrintFlags.AddFlags(cmd)//设置print选项

	cmd.Flags().String("generator", "service/v2", i18n.T("The name of the API generator to use. There are 2 generators: 'service/v1' and 'service/v2'. The only difference between them is that service port in v1 is named 'default', while it is left unnamed in v2. Default is 'service/v2'."))//设置generator选项
	cmd.Flags().String("protocol", "", i18n.T("The network protocol for the service to be created. Default is 'TCP'."))//设置protocol选项
	cmd.Flags().String("port", "", i18n.T("The port that the service should serve on. Copied from the resource being exposed, if unspecified"))//设置port选项
	cmd.Flags().String("type", "", i18n.T("Type for this service: ClusterIP, NodePort, LoadBalancer, or ExternalName. Default is 'ClusterIP'."))//设置type选项
	cmd.Flags().String("load-balancer-ip", "", i18n.T("IP to assign to the LoadBalancer. If empty, an ephemeral IP will be created and used (cloud-provider specific)."))//设置load-balancer-ip选项
	cmd.Flags().String("selector", "", i18n.T("A label selector to use for this service. Only equality-based selector requirements are supported. If empty (the default) infer the selector from the replication controller or replica set.)"))//设置selector选项
	cmd.Flags().StringP("labels", "l", "", "Labels to apply to the service created by this call.")//设置labels选项
	cmd.Flags().String("container-port", "", i18n.T("Synonym for --target-port"))
	cmd.Flags().MarkDeprecated("container-port", "--container-port will be removed in the future, please use --target-port instead")
	cmd.Flags().String("target-port", "", i18n.T("Name or number for the port on the container that the service should direct traffic to. Optional."))//设置target-port选项
	cmd.Flags().String("external-ip", "", i18n.T("Additional external IP address (not managed by Kubernetes) to accept for the service. If this IP is routed to a node, the service can be accessed by this IP in addition to its generated service IP."))//设置external-ip选项
	cmd.Flags().String("overrides", "", i18n.T("An inline JSON override for the generated object. If this is non-empty, it is used to override the generated object. Requires that the object supply a valid apiVersion field."))//设置overrides选项
	cmd.Flags().String("name", "", i18n.T("The name for the newly created object."))//设置name选项
	cmd.Flags().String("session-affinity", "", i18n.T("If non-empty, set the session affinity for the service to this; legal values: 'None', 'ClientIP'"))//设置session-affinity选项
	cmd.Flags().String("cluster-ip", "", i18n.T("ClusterIP to be assigned to the service. Leave empty to auto-allocate, or set to 'None' to create a headless service."))//设置cluster-ip选项

	usage := "identifying the resource to expose a service"
	cmdutil.AddFilenameOptionFlags(cmd, &o.FilenameOptions, usage)//设置-f选项
	cmdutil.AddDryRunFlag(cmd)//设置dry-run选项
	cmdutil.AddApplyAnnotationFlags(cmd)//设置save-config选项
	return cmd
}
//准备函数
func (o *ExposeServiceOptions) Complete(f cmdutil.Factory, cmd *cobra.Command) error {
	o.DryRun = cmdutil.GetDryRunFlag(cmd)//设置dry-run

	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

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

	o.DynamicClient, err = f.DynamicClient()//设置client
	if err != nil {
		return err
	}

	o.Generators = generateversioned.GeneratorFn//获取generator函数
	o.Builder = f.NewBuilder()//设置builder
	o.CanBeExposed = polymorphichelpers.CanBeExposedFn//是否可expose函数
	o.MapBasedSelectorForObject = polymorphichelpers.MapBasedSelectorForObjectFn//从对象获取selector函数
	o.ProtocolsForObject = polymorphichelpers.ProtocolsForObjectFn//从对象获取protocol函数
	o.PortsForObject = polymorphichelpers.PortsForObjectFn//从对象获取port函数

	o.Mapper, err = f.ToRESTMapper()//设置mapper
	if err != nil {
		return err
	}

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

	return err
}
//运行
func (o *ExposeServiceOptions) RunExpose(cmd *cobra.Command, args []string) error {
	r := o.Builder.
		WithScheme(scheme.Scheme, scheme.Scheme.PrioritizedVersionsAllGroups()...).
		ContinueOnError().
		NamespaceParam(o.Namespace).DefaultNamespace().
		FilenameParam(o.EnforceNamespace, &o.FilenameOptions).
		ResourceTypeOrNameArgs(false, args...).
		Flatten().
		Do()//构造Result对象
	err := r.Err()
	if err != nil {
		return cmdutil.UsageErrorf(cmd, err.Error())
	}

	// Get the generator, setup and validate all required parameters
	generatorName := cmdutil.GetFlagString(cmd, "generator")//获取generator name
	generators := o.Generators("expose")//获取generator map
	generator, found := generators[generatorName]//获取generator
	if !found {
		return cmdutil.UsageErrorf(cmd, "generator %q not found.", generatorName)
	}
	names := generator.ParamNames()//获取generator参数名称

	err = r.Visit(func(info *resource.Info, err error) error {//访问result对象
		if err != nil {
			return err
		}

		mapping := info.ResourceMapping()//获取mapping
		if err := o.CanBeExposed(mapping.GroupVersionKind.GroupKind()); err != nil {//判断是否可以export
			return err
		}

		params := generate.MakeParams(cmd, names)//构造generator Params
		name := info.Name
		if len(name) > validation.DNS1035LabelMaxLength {//判断名称是否超出长度
			name = name[:validation.DNS1035LabelMaxLength]
		}
		params["default-name"] = name//设置generator params

		// For objects that need a pod selector, derive it from the exposed object in case a user
		// didn't explicitly specify one via --selector
		if s, found := params["selector"]; found && generate.IsZero(s) {从参数获取selector,如果存在并为空
			s, err := o.MapBasedSelectorForObject(info.Object)//从Info对象里获取selector
			if err != nil {
				return cmdutil.UsageErrorf(cmd, "couldn't retrieve selectors via --selector flag or introspection: %v", err)
			}
			params["selector"] = s//设置selector参数
		}

		isHeadlessService := params["cluster-ip"] == "None"//设置是否无头service

		// For objects that need a port, derive it from the exposed object in case a user
		// didn't explicitly specify one via --port
		if port, found := params["port"]; found && generate.IsZero(port) {//从params获取port,如果存在并且为空
			ports, err := o.PortsForObject(info.Object)//从info对象获取prots
			if err != nil {
				return cmdutil.UsageErrorf(cmd, "couldn't find port via --port flag or introspection: %v", err)
			}
			switch len(ports) {
			case 0:
				if !isHeadlessService {
					return cmdutil.UsageErrorf(cmd, "couldn't find port via --port flag or introspection")
				}
			case 1:
				params["port"] = ports[0]
			default:
				params["ports"] = strings.Join(ports, ",")
			}
		}

		// Always try to derive protocols from the exposed object, may use
		// different protocols for different ports.
		if _, found := params["protocol"]; found {//从参数里获取protocol,如果存在
			protocolsMap, err := o.ProtocolsForObject(info.Object)//从info里获取protocol
			if err != nil {
				return cmdutil.UsageErrorf(cmd, "couldn't find protocol via introspection: %v", err)
			}
			if protocols := generate.MakeProtocols(protocolsMap); !generate.IsZero(protocols) {
				params["protocols"] = protocols//设置protocols参数
			}
		}

		if generate.IsZero(params["labels"]) {//从params获取labels,并且为空
			labels, err := meta.NewAccessor().Labels(info.Object)//从info对象获取labels
			if err != nil {
				return err
			}
			params["labels"] = polymorphichelpers.MakeLabels(labels)//设置labels
		}
		if err = generate.ValidateParams(names, params); err != nil {//验证参数是否有效
			return err
		}
		// Check for invalid flags used against the present generator.
		if err := generate.EnsureFlagsValid(cmd, generators, generatorName); err != nil {//验证flag是否有效
			return err
		}

		// Generate new object
		object, err := generator.Generate(params)//从generator生成对象
		if err != nil {
			return err
		}

		if inline := cmdutil.GetFlagString(cmd, "overrides"); len(inline) > 0 {//如果overrides不为空
			codec := runtime.NewCodec(scheme.DefaultJSONEncoder(), scheme.Codecs.UniversalDecoder(scheme.Scheme.PrioritizedVersionsAllGroups()...))
			object, err = cmdutil.Merge(codec, object, inline)//合并对象和overrides
			if err != nil {
				return err
			}
		}

		if err := o.Recorder.Record(object); err != nil {//设置change-cause注解
			klog.V(4).Infof("error recording current command: %v", err)
		}

		if o.DryRun {//干跑打印结果
			return o.PrintObj(object, o.Out)
		}
		if err := util.CreateOrUpdateAnnotation(cmdutil.GetFlagBool(cmd, cmdutil.ApplyAnnotationsFlag), object, scheme.DefaultJSONEncoder()); err != nil {//设置last-applied-configuration注解
			return err
		}

		asUnstructured := &unstructured.Unstructured{}
		if err := scheme.Scheme.Convert(object, asUnstructured, nil); err != nil {//把对象转为非结构化的
			return err
		}
		gvks, _, err := unstructuredscheme.NewUnstructuredObjectTyper().ObjectKinds(asUnstructured)//获取groupversionkinds
		if err != nil {
			return err
		}
		objMapping, err := o.Mapper.RESTMapping(gvks[0].GroupKind(), gvks[0].Version)//获取mapping
		if err != nil {
			return err
		}
		// Serialize the object with the annotation applied.
		actualObject, err := o.DynamicClient.Resource(objMapping.Resource).Namespace(o.Namespace).Create(asUnstructured, metav1.CreateOptions{})//创建service对象
		if err != nil {
			return err
		}

		return o.PrintObj(actualObject, o.Out)//打印结果
	})
	if err != nil {
		return err
	}
	return nil
}

### 设计和实现CI/CD流程 #### 1. 明确需求与目标 在设计 CI/CD 流程之前,需明确团队的具体需求以及期望达成的目标。例如,减少手动操作、提升交付速度或增强软件质量等[^2]。 #### 2. 工具选型 选择适合项目的 CI/CD 工具至关重要。常见的工具有 Jenkins、Travis CI、CircleCI、GitLab CI/CD 和 GitHub Actions 等。这些工具提供了丰富的插件支持和灵活的配置选项,能够满足不同规模项目的需求[^3]。 #### 3. 配置版本控制系统 CI/CD 的核心依赖于版本控制系统的集成。推荐使用 Git 或其他分布式版本控制系统作为基础架构的一部分。所有的代码变更都需要通过版本控制系统触发后续的流水线执行。 #### 4. 自动化构建过程 构建阶段涉及编译源码并生成可运行的应用程序包。对于前端项目而言,可能需要打包静态资源文件;而对于后端服务,则可能是创建 Docker 镜像或其他形式的二进制文件。以下是基于 Node.js 前端应用的一个简单示例: ```javascript // package.json 脚本部分定义 { "scripts": { "build": "webpack --mode production" } } ``` 对于容器化环境下的应用程序来说,Dockerfile 是不可或缺的部分之一: ```dockerfile # 使用官方Node镜像为基础 FROM node:14-alpine # 设置工作目录 WORKDIR /app # 复制package*.json 到工作区 COPY package*.json ./ # 安装依赖项 RUN npm install # 添加应用源代码至容器内 COPY . . # 构建应用 RUN npm run build # 指定暴露端口 EXPOSE 8080 # 启动命令 CMD ["npm", "start"] ``` #### 5. 实施自动化测试策略 为了保障每次提交的质量,在部署前应进行全面覆盖的功能性和非功能性测试。单元测试、集成测试乃至性能压测都可以被纳入到这个环节当中[^1]。 #### 6. 部署机制的选择 依据业务场景的不同可以选择蓝绿部署(Blue-Green Deployment)或者金丝雀发布(Canary Release)等方式降低风险。下面是一个简单的Shell脚本来展示如何利用kubectl完成Kubernetes集群上的滚动更新: ```bash #!/bin/bash NAMESPACE="default" DEPLOYMENT_NAME="example-app" echo "Starting deployment..." # Apply new configuration files. kubectl apply -f ./deployment.yaml -n $NAMESPACE # Wait until the rollout is complete. kubectl rollout status deploy/$DEPLOYMENT_NAME -n $NAMESPACE if [[ $? != 0 ]]; then echo "Deployment failed!" exit 1 fi echo "Deployment successful." ``` #### 7. 监控与反馈循环建立 最后一步就是持续监控已上线的服务状态,并收集日志信息用于分析潜在问题所在之处。Sentry 这样的错误追踪平台可以帮助快速定位线上 bug[^3]。 ---
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