root.go

package main

import (
	"flag"
	"os"

	"github.com/spf13/cobra"
	"github.com/spf13/pflag"
	utilflag "k8s.io/apiserver/pkg/util/flag"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/kubernetes/pkg/kubectl/cmd/util"
	"k8s.io/kubernetes/pkg/kubectl/plugins"
)

func NewRootCmd(plugin bool) *cobra.Command {
	var (
		enableAnalytics = true
	)
	var rootCmd = &cobra.Command{
		Use:               "kubectl-plugin-demo",
		Short:             `Tamal's kubectl plugin'`,
		DisableAutoGenTag: true,
		PersistentPreRun: func(c *cobra.Command, args []string) {
			//c.Flags().VisitAll(func(flag *pflag.Flag) {
			//	stdlog.Printf("FLAG: --%s=%q", flag.Name, flag.Value)
			//})
		},
	}
	util.NewFactory(nil)

	flags := rootCmd.PersistentFlags()
	clientConfig := BindFlags(flags, plugin)
	// ref: https://github.com/kubernetes/kubernetes/issues/17162#issuecomment-225596212
	flag.CommandLine.Parse([]string{})
	rootCmd.PersistentFlags().BoolVar(&enableAnalytics, "analytics", enableAnalytics, "Test persistent flag at plugin level")

	rootCmd.AddCommand(NewCmdList(clientConfig))
	rootCmd.AddCommand(NewCmdEnv())
	rootCmd.AddCommand(NewCmdInstall(rootCmd))
	return rootCmd
}

func BindFlags(flags *pflag.FlagSet, plugin bool) clientcmd.ClientConfig {
	flags.AddGoFlagSet(flag.CommandLine)
	// Normalize all flags that are coming from other packages or pre-configurations
	// a.k.a. change all "_" to "-". e.g. glog package
	flags.SetNormalizeFunc(utilflag.WordSepNormalizeFunc)
	clientConfig := util.DefaultClientConfig(flags)
	if plugin {
		loadFromEnv(flags, "kubeconfig")
		loadFromEnv(flags, clientcmd.FlagClusterName)
		loadFromEnv(flags, clientcmd.FlagAuthInfoName)
		loadFromEnv(flags, clientcmd.FlagContext)
		loadFromEnv(flags, clientcmd.FlagNamespace)
		loadFromEnv(flags, clientcmd.FlagAPIServer)
		loadFromEnv(flags, clientcmd.FlagInsecure)
		loadFromEnv(flags, clientcmd.FlagCertFile)
		loadFromEnv(flags, clientcmd.FlagKeyFile)
		loadFromEnv(flags, clientcmd.FlagCAFile)
		loadFromEnv(flags, clientcmd.FlagBearerToken)
		loadFromEnv(flags, clientcmd.FlagImpersonate)
		loadFromEnv(flags, clientcmd.FlagImpersonateGroup)
		loadFromEnv(flags, clientcmd.FlagUsername)
		loadFromEnv(flags, clientcmd.FlagPassword)
		loadFromEnv(flags, clientcmd.FlagTimeout)

		loadFromEnv(flags, "alsologtostderr")
		loadFromEnv(flags, "log-backtrace-at")
		loadFromEnv(flags, "log-dir")
		loadFromEnv(flags, "logtostderr")
		loadFromEnv(flags, "stderrthreshold")
		loadFromEnv(flags, "v")
		loadFromEnv(flags, "vmodule")
	}
	return clientConfig
}

func loadFromEnv(flags *pflag.FlagSet, name string) {
	v, found := os.LookupEnv(plugins.FlagToEnvName(name, "KUBECTL_PLUGINS_GLOBAL_FLAG_"))
	if found && (name != clientcmd.FlagImpersonateGroup || v != "[]") {
		flags.Set(name, v)
	}
}