kubectl源码分析之expose

巧了我就是萌 提交于 2020-08-09 02:24:58

发布一个k8s部署视频:https://edu.csdn.net/course/detail/26967

课程内容:各种k8s部署方式。包括minikube部署,kubeadm部署,kubeasz部署,rancher部署,k3s部署。包括开发测试环境部署k8s,和生产环境部署k8s。

腾讯课堂连接地址https://ke.qq.com/course/478827?taid=4373109931462251&tuin=ba64518

第二个视频发布  https://edu.csdn.net/course/detail/27109

腾讯课堂连接地址https://ke.qq.com/course/484107?tuin=ba64518

介绍主要的k8s资源的使用配置和命令。包括configmap,pod,service,replicaset,namespace,deployment,daemonset,ingress,pv,pvc,sc,role,rolebinding,clusterrole,clusterrolebinding,secret,serviceaccount,statefulset,job,cronjob,podDisruptionbudget,podSecurityPolicy,networkPolicy,resourceQuota,limitrange,endpoint,event,conponentstatus,node,apiservice,controllerRevision等。

第三个视频发布:https://edu.csdn.net/course/detail/27574

详细介绍helm命令,学习helm chart语法,编写helm chart。深入分析各项目源码,学习编写helm插件

第四个课程发布:https://edu.csdn.net/course/detail/28488

本课程将详细介绍k8s所有命令,以及命令的go源码分析,学习知其然,知其所以然
————————————————

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
}

 

 

 

 

 

 

 

标签
易学教程内所有资源均来自网络或用户发布的内容,如有违反法律规定的内容欢迎反馈
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!