Add env flag to load .env file.

cmd/root.go

@@ -32,6 +32,7 @@ import (
 
 var (
 	cfgFile        string
+	envFile        string
 	subCommand     string
 	logWithCommand log.Entry
 )
@@ -102,6 +103,7 @@ func init() {
 	viper.AutomaticEnv()
 
 	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file location")
+	rootCmd.PersistentFlags().StringVar(&envFile, "env", "", "environment file location")
 
 	rootCmd.PersistentFlags().String("client-ipcPath", "", "location of geth.ipc file")
 	rootCmd.PersistentFlags().String("log-level", log.InfoLevel.String(), "log level (trace, debug, info, warn, error, fatal, panic)")
@@ -124,21 +126,32 @@ func init() {
 }
 
 func initConfig() {
-	if cfgFile == "" {
-		log.Warn("No config file passed with --config flag")
-		return
+	if cfgFile == "" && envFile == "" {
+		log.Fatal("No configuration file specified, use --config , --env flag to provide configuration")
 	}
 
-	viper.SetConfigFile(cfgFile)
-	if err := viper.ReadInConfig(); err != nil {
-		log.Fatalf("Couldn't read config file: %s", err.Error())
-	}
-
-	log.Infof("Using config file: %s", viper.ConfigFileUsed())
-
-	if filepath.Ext(cfgFile) == ".env" {
-		if err := godotenv.Load(cfgFile); err != nil {
-			log.Fatalf("Failed to set environment variable from config file: %s", err.Error())
+	if cfgFile != "" {
+		if filepath.Ext(cfgFile) != ".toml" {
+			log.Fatal("Provide .toml file for --config flag")
 		}
+
+		viper.SetConfigFile(cfgFile)
+		if err := viper.ReadInConfig(); err != nil {
+			log.Fatalf("Couldn't read config file: %s", err.Error())
+		}
+
+		log.Infof("Using config file: %s", viper.ConfigFileUsed())
+	}
+
+	if envFile != "" {
+		if filepath.Ext(envFile) != ".env" {
+			log.Fatal("Provide .env file for --env flag")
+		}
+
+		if err := godotenv.Load(envFile); err != nil {
+			log.Fatalf("Failed to set environment variable from env file: %s", err.Error())
+		}
+
+		log.Infof("Using env file: %s", envFile)
 	}
 }