cobra sample

main.go

package main

import (
	"fmt"
	"os"
	"strings"
	"time"

	homedir "github.com/mitchellh/go-homedir"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
)

func main() {
	Execute()
}

const (
	cfgAddress  = "address"
	cfgInterval = "interval"
	cfgCount    = "count"
	cfgPort     = "nested.port"
)

var cfgFile string

var config struct {
	Address  string
	Interval time.Duration
	Count    int
	Nested   struct {
		Port int
	}
}

var rootCmd = &cobra.Command{
	Use: "cobra-123",
	Run: func(cmd *cobra.Command, args []string) {
		fmt.Printf("%#v\n", config)
	},
}

// Execute adds all child commands to the root command and sets flags appropriately.
// This is called by main.main(). It only needs to happen once to the rootCmd.
func Execute() {
	if err := rootCmd.Execute(); err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
}

func init() {
	cobra.OnInitialize(initConfig)
	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.cobra-123.yaml)")

	rootCmd.PersistentFlags().String(cfgAddress, "", "The address")
	rootCmd.PersistentFlags().Duration(cfgInterval, 1*time.Second, "The interval")
	rootCmd.PersistentFlags().Int(cfgCount, 1000, "The count")
	rootCmd.PersistentFlags().Int(cfgPort, 200, "The port")

	//rootCmd.MarkPersistentFlagRequired(cfgAddress)

	viper.BindPFlag(cfgAddress, rootCmd.PersistentFlags().Lookup(cfgAddress))
	viper.BindPFlag(cfgInterval, rootCmd.PersistentFlags().Lookup(cfgInterval))
	viper.BindPFlag(cfgCount, rootCmd.PersistentFlags().Lookup(cfgCount))
	viper.BindPFlag(cfgPort, rootCmd.PersistentFlags().Lookup(cfgPort))
}

// initConfig reads in config file and ENV variables if set.
func initConfig() {
	if cfgFile != "" {
		// Use config file from the flag.
		viper.SetConfigFile(cfgFile)
	} else {
		// Find home directory.
		home, err := homedir.Dir()
		if err != nil {
			fmt.Println(err)
			os.Exit(1)
		}

		// Search config in home directory with name ".zdb" (without extension).
		viper.AddConfigPath(home)
		viper.AddConfigPath(".")
		viper.SetConfigName("sample")
		viper.SetConfigType("yaml")
	}

	viper.AutomaticEnv() // read in environment variables that match
	replacer := strings.NewReplacer("-", "_")
	viper.SetEnvKeyReplacer(replacer)

	// If a config file is found, read it in.
	if err := viper.ReadInConfig(); err == nil {
		fmt.Println("Using config file:", viper.ConfigFileUsed())
	}

	if err := viper.Unmarshal(&config); err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
}