Allow config files to inherit from other config files

serv/cmd.go

@@ -150,13 +150,25 @@ func initLog() *zerolog.Logger {
 }
 
 func initConf() (*config, error) {
-	vi := newConfig()
+	vi := newConfig(getConfigName())
 
 	if err := vi.ReadInConfig(); err != nil {
 		return nil, err
 	}
 
-	c := &config{}
+	inherit := vi.GetString("inherit")
+	if len(inherit) != 0 {
+		vi = newConfig(inherit)
+
+		if err := vi.ReadInConfig(); err != nil {
+			return nil, err
+		}
+
+		vi.SetConfigName(getConfigName())
+		vi.MergeInConfig()
+	}
+
+	c := &config{Viper: vi}
 
 	if err := vi.Unmarshal(c); err != nil {
 		return nil, fmt.Errorf("unable to decode config, %v", err)

serv/cmd_conf.go

@@ -15,13 +15,12 @@ func cmdConfDump(cmd *cobra.Command, args []string) {
 
 	fname := fmt.Sprintf("%s.%s", getConfigName(), args[0])
 
-	vi := newConfig()
-
-	if err := vi.ReadInConfig(); err != nil {
-		logger.Fatal().Err(err).Send()
+	conf, err := initConf()
+	if err != nil {
+		logger.Fatal().Err(err).Msg("failed to read config")
 	}
 
-	if err := vi.WriteConfigAs(fname); err != nil {
+	if err := conf.Viper.WriteConfigAs(fname); err != nil {
 		logger.Fatal().Err(err).Send()
 	}
 

serv/config.go

@@ -9,6 +9,8 @@ import (
 )
 
 type config struct {
+	*viper.Viper
+
 	AppName        string `mapstructure:"app_name"`
 	Env            string
 	HostPort       string `mapstructure:"host_port"`
@@ -134,16 +136,16 @@ type configRole struct {
 	}
 }
 
-func newConfig() *viper.Viper {
+func newConfig(name string) *viper.Viper {
 	vi := viper.New()
 
 	vi.SetEnvPrefix("SG")
 	vi.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
 	vi.AutomaticEnv()
 
+	vi.SetConfigName(name)
 	vi.AddConfigPath(confPath)
 	vi.AddConfigPath("./config")
-	vi.SetConfigName(getConfigName())
 
 	vi.SetDefault("host_port", "0.0.0.0:8080")
 	vi.SetDefault("web_ui", false)

serv/serv.go

@@ -148,7 +148,15 @@ func startHTTP() {
 		db.Close()
 	})
 
-	fmt.Printf("%s listening on %s (%s)\n", serverName, hostPort, conf.Env)
+	var ident string
+
+	if len(conf.AppName) == 0 {
+		ident = conf.Env
+	} else {
+		ident = conf.AppName
+	}
+
+	fmt.Printf("%s listening on %s (%s)\n", serverName, hostPort, ident)
 
 	if err := srv.ListenAndServe(); err != http.ErrServerClosed {
 		logger.Error().Err(err).Msg("server closed")