kubectl源码分析之create quota

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
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type QuotaOpts struct {
	CreateSubcommandOptions *CreateSubcommandOptions  //create命令公用的option
}

//创建create quota命令
func NewCmdCreateQuota(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra.Command {
	options := &QuotaOpts{//初始化option
		CreateSubcommandOptions: NewCreateSubcommandOptions(ioStreams),
	}

	cmd := &cobra.Command{//创建cobra命令
		Use:                   "quota NAME [--hard=key1=value1,key2=value2] [--scopes=Scope1,Scope2] [--dry-run=bool]",
		DisableFlagsInUseLine: true,
		Aliases:               []string{"resourcequota"},
		Short:                 i18n.T("Create a quota with the specified name."),
		Long:                  quotaLong,
		Example:               quotaExample,
		Run: func(cmd *cobra.Command, args []string) {
			cmdutil.CheckErr(options.Complete(f, cmd, args))//做准备工作
			cmdutil.CheckErr(options.Run())//执行命令逻辑
		},
	}

	options.CreateSubcommandOptions.PrintFlags.AddFlags(cmd)//创建print选项

	cmdutil.AddApplyAnnotationFlags(cmd)//创建save-config选项
	cmdutil.AddValidateFlags(cmd)//创建validate选项
	cmdutil.AddGeneratorFlags(cmd, generateversioned.ResourceQuotaV1GeneratorName)//创建validate选项
	cmd.Flags().String("hard", "", i18n.T("A comma-delimited set of resource=quantity pairs that define a hard limit."))//创建hard选项
	cmd.Flags().String("scopes", "", i18n.T("A comma-delimited set of quota scopes that must all match each object tracked by the quota."))//创建scope选项
	return cmd
}

//准备工作
func (o *QuotaOpts) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
	name, err := NameFromCommandArgs(cmd, args)//获取quota name
	if err != nil {
		return err
	}

	var generator generate.StructuredGenerator
	switch generatorName := cmdutil.GetFlagString(cmd, "generator"); generatorName {//后去generator，并判断generator是否有效
	case generateversioned.ResourceQuotaV1GeneratorName:
		generator = &generateversioned.ResourceQuotaGeneratorV1{//生成generator
			Name:   name,
			Hard:   cmdutil.GetFlagString(cmd, "hard"),
			Scopes: cmdutil.GetFlagString(cmd, "scopes"),
		}
	default:
		return errUnsupportedGenerator(cmd, generatorName)
	}

	return o.CreateSubcommandOptions.Complete(f, cmd, args, generator)//运行createsubcommandoption的complete
}

//create命令公用的option的complete
func (o *CreateSubcommandOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string, generator generate.StructuredGenerator) error {
	name, err := NameFromCommandArgs(cmd, args)//获取资源名称
	if err != nil {
		return err
	}

	o.Name = name//设置名称
	o.StructuredGenerator = generator//设置generator
	o.DryRun = cmdutil.GetDryRunFlag(cmd)//后去dry-run值
	o.CreateAnnotation = cmdutil.GetFlagBool(cmd, cmdutil.ApplyAnnotationsFlag)//后去save-config选项值

	if o.DryRun {//干跑运行干跑的complete
		o.PrintFlags.Complete("%s (dry run)")
	}
	printer, err := o.PrintFlags.ToPrinter()//printflag转化为printer
	if err != nil {
		return err
	}

	o.PrintObj = func(obj kruntime.Object, out io.Writer) error {
		return printer.PrintObj(obj, out)//设置printObj函数
	}

	o.Namespace, o.EnforceNamespace, err = f.ToRawKubeConfigLoader().Namespace()//获取namespace和强制namspace
	if err != nil {
		return err
	}

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

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

	return nil
}

func (o *QuotaOpts) Run() error {//运行run
	return o.CreateSubcommandOptions.Run()//运行createSubCommandOption的run
}

func (o *CreateSubcommandOptions) Run() error {
	obj, err := o.StructuredGenerator.StructuredGenerate()//根据generator获取结构化的对象
	if err != nil {
		return err
	}
	if !o.DryRun {//非干跑
		// create subcommands have compiled knowledge of things they create, so type them directly
		gvks, _, err := scheme.Scheme.ObjectKinds(obj)//从obj中获取groupversionkind
		if err != nil {
			return err
		}
		gvk := gvks[0]
		mapping, err := o.Mapper.RESTMapping(schema.GroupKind{Group: gvk.Group, Kind: gvk.Kind}, gvk.Version)//根据greoup kind version获取mapping
		if err != nil {
			return err
		}

		if err := util.CreateOrUpdateAnnotation(o.CreateAnnotation, obj, scheme.DefaultJSONEncoder()); err != nil {//创建更新last-applied-configuration注解
			return err
		}

		asUnstructured := &unstructured.Unstructured{}//创建非结构化对象

		if err := scheme.Scheme.Convert(obj, asUnstructured, nil); err != nil {//把obj转化为非结构化对象
			return err
		}
		if mapping.Scope.Name() == meta.RESTScopeNameRoot {//判断mapping的scope
			o.Namespace = ""
		}
		actualObject, err := o.DynamicClient.Resource(mapping.Resource).Namespace(o.Namespace).Create(asUnstructured, metav1.CreateOptions{})//用client创建quota对象
		if err != nil {
			return err
		}

		// ensure we pass a versioned object to the printer
		obj = actualObject//把服务器返回结构设置到obj
	} else {
		if meta, err := meta.Accessor(obj); err == nil && o.EnforceNamespace {
			meta.SetNamespace(o.Namespace)
		}
	}

	return o.PrintObj(obj, o.Out)//打印obj，到输出
}

来源：oschina

链接：https://my.oschina.net/u/4350128/blog/4273694

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