ble-sensors/cmd/root.go

package cmd

import (
	"fmt"
	"os"

	"github.com/spf13/cobra"
	"go.uber.org/zap"

	"github.com/spf13/viper"
)

var configFile string
var debug bool
var logger *zap.Logger

// rootCmd represents the base command when called without any subcommands
var rootCmd = &cobra.Command{
	Use:   "ble-sensors",
	Short: "A brief description of your application",
	Long: `A longer description that spans multiple lines and likely contains
examples and usage of using your application. For example:

Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.`,
	// Uncomment the following line if your bare application
	// has an action associated with it:
	//	Run: func(cmd *cobra.Command, args []string) { },
}

// 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(&configFile, "config", "", "config file")
	rootCmd.PersistentFlags().BoolVar(&debug, "debug", false, "Turn debug messages on.")
}

func initConfig() {
	if configFile != "" {
		viper.SetConfigFile(configFile)
	} else {
		viper.AddConfigPath(".")
		viper.AddConfigPath("/opt/ble-sensors")
		viper.SetConfigName("ble-sensors")
	}
	var err error
	if debug {
		logger, err = zap.NewDevelopment()
	} else {
		logger, err = zap.NewProduction()
	}
	if err != nil {
		fmt.Printf("unable to initialize logger: %s\n", err.Error())
		os.Exit(1)
	}
	err = viper.ReadInConfig()
	if err != nil {
		fmt.Printf("unable to open config file: %s\n", err.Error())
		os.Exit(1)
	}
	logger.Info("found config file", zap.String("filename", viper.ConfigFileUsed()))
}