config.go

package main

import (
	"os"
	"strings"

	"github.com/adrg/xdg"
	"github.com/rs/zerolog/log"
	"github.com/spf13/viper"
)

var configName = "tailscale-custom-domain-dns.toml"

func loadConfig() {
	// Find the config file
	configPath, err := xdg.SearchConfigFile(configName)
	if err != nil {
		log.Error().Msg("Could not find config file")
		log.Error().Msgf(`No config file "%s" found in directories:`, configName)
		log.Error().Msgf("  %s", xdg.ConfigHome)
		for _, configDir := range xdg.ConfigDirs {
			log.Error().Msgf("  %s", configDir)
		}
		log.Error().Msg("You can generate config with `tailscale-custom-domain-dns --generate-config`")
		log.Fatal().Err(err).Msg("Exiting")
	}

	// Setup viper
	viper.SetConfigName("tailscale-custom-domain-dns")
	viper.SetConfigType("toml")

	// Read configs from environment variables
	viper.SetEnvPrefix("TSDNS")
	viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_", "-", ""))
	viper.AutomaticEnv()

	// Set some default values
	viper.SetDefault("log-level", "info")
	viper.SetDefault("fetcher.interval", "1h")
	viper.SetDefault("dns-server.port", 53)
	viper.SetDefault("tailscale.hostname", "tailscale-custom-domain-dns")
	viper.SetDefault("tailscale.ephemeral", false)
	viper.SetDefault("aliases.subdomains", map[string]string{})

	// Read the config
	configFile, err := os.Open(configPath)
	if err != nil {
		log.Fatal().Err(err).Str("path", configPath).Msg("could not open conf file")
	}
	err = viper.ReadConfig(configFile)
	if err != nil {
		log.Fatal().Err(err).Str("path", configPath).Msg("could not parse conf file")
	}

	// Check for required config options
	requiredConfigs := []string{
		"domain",
		"tailscale.organization-name",
		"tailscale.auth-key",
		"tailscale.oauth-client-id",
		"tailscale.oauth-client-secret",
	}
	var missingConfigs []string
	for _, requiredConfigName := range requiredConfigs {
		if !viper.IsSet(requiredConfigName) {
			missingConfigs = append(missingConfigs, requiredConfigName)
		}
	}
	if len(missingConfigs) != 0 {
		log.Fatal().Msgf("Missing required config values:\n - %s\n", strings.Join(missingConfigs, "\n - "))
	}
}