dyndns/cmd/write-default-config.go

package cmd

import (
	"log"
	"path/filepath"

	"github.com/spf13/cobra"
	"github.com/spf13/viper"
)

var cmdWriteDefaultConfig = &cobra.Command{
	Use:   "write-default-config",
	Short: "Write default config to file",
	Long: `Writes the default configuration to a new configuration file, which
can be further customized by you.`,
	// Run is defined inline in init to capture Flag variables in the closure
}

func init() {
	rootCmd.AddCommand(cmdWriteDefaultConfig)
	filename := cmdWriteDefaultConfig.Flags().StringP("filename", "f", "default-config.yml",
		"The config filename to use, defaults to conf-default.yml")

	cmdWriteDefaultConfig.Run = func(cmd *cobra.Command, args []string) {
		writeDefaultConfig(*filename)
	}
}

func writeDefaultConfig(filename string) {
	if filepath.Ext(filename) != ".yml" {
		log.Fatalln("The default config filename must end in .yml")
	}

	viper.Reset()
	setAllConfigDefaults()
	err := viper.WriteConfigAs(filename)
	if err != nil {
		log.Fatalf("Could not write default configuration file %s: %s", filename, err)
	}
	log.Printf("Default configuration written as %s", filename)
}