kubectl源码分析之create configmap

发布一个k8s部署视频：https://edu.youkuaiyun.com/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.youkuaiyun.com/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.youkuaiyun.com/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.youkuaiyun.com/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 ConfigMapOpts struct {//选项结构体
	CreateSubcommandOptions *CreateSubcommandOptions
}

//创建configmap cobra命令
func NewCmdCreateConfigMap(f cmdutil.Factory, ioStreams genericclioptions.IOStreams) *cobra.Command {
	options := &ConfigMapOpts{//初始化选项结构体
		CreateSubcommandOptions: NewCreateSubcommandOptions(ioStreams),
	}

	cmd := &cobra.Command{//创建cobra命令
		Use:                   "configmap NAME [--from-file=[key=]source] [--from-literal=key1=value1] [--dry-run]",
		DisableFlagsInUseLine: true,
		Aliases:               []string{"cm"},
		Short:                 i18n.T("Create a configmap from a local file, directory or literal value"),
		Long:                  configMapLong,
		Example:               configMapExample,
		Run: func(cmd *cobra.Command, args []string) {
			cmdutil.CheckErr(options.Complete(f, cmd, args))//准备
			cmdutil.CheckErr(options.Run())//运行命令
		},
	}

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

	cmdutil.AddApplyAnnotationFlags(cmd)//创建save-config选项
	cmdutil.AddValidateFlags(cmd)//创建validate选项
	cmdutil.AddGeneratorFlags(cmd, generateversioned.ConfigMapV1GeneratorName)//创建generator选项
	cmd.Flags().StringSlice("from-file", []string{}, "Key file can be specified using its file path, in which case file basename will be used as configmap key, or optionally with a key and file path, in which case the given key will be used.  Specifying a directory will iterate each named file in the directory whose basename is a valid configmap key.")//创建from-file选项
	cmd.Flags().StringArray("from-literal", []string{}, "Specify a key and literal value to insert in configmap (i.e. mykey=somevalue)")//创建from-literal选项
	cmd.Flags().String("from-env-file", "", "Specify the path to a file to read lines of key=val pairs to create a configmap (i.e. a Docker .env file).")//创建from-env-file选项
	cmd.Flags().Bool("append-hash", false, "Append a hash of the configmap to its name.")//创建append-hash选项
	return cmd
}

//做一些准备工作
func (o *ConfigMapOpts) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
	name, err := NameFromCommandArgs(cmd, args)//从参数获取资源名称
	if err != nil {
		return err
	}

	var generator generate.StructuredGenerator
	switch generatorName := cmdutil.GetFlagString(cmd, "generator"); generatorName {
	case generateversioned.ConfigMapV1GeneratorName://获取generator选项并判断
		generator = &generateversioned.ConfigMapGeneratorV1{//构造generator对象
			Name:           name,
			FileSources:    cmdutil.GetFlagStringSlice(cmd, "from-file"),
			LiteralSources: cmdutil.GetFlagStringArray(cmd, "from-literal"),
			EnvFileSource:  cmdutil.GetFlagString(cmd, "from-env-file"),
			AppendHash:     cmdutil.GetFlagBool(cmd, "append-hash"),
		}
	default:
		return errUnsupportedGenerator(cmd, generatorName)
	}

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

其他和上一个命令一样，不做介绍