chore: improve error message if config file not present

Signed-off-by: Bradley Jones <bradley.jones@anchore.com>

cmd/cmd.go

@@ -42,10 +42,23 @@ func Execute() {
 
 func InitAppConfig() {
 	cfg, err := config.LoadConfigFromFile(viper.GetViper(), &cliOnlyOpts)
-	if err != nil {
-		fmt.Printf("failed to load application config: \n\t%+v\n", err)
+	switch err {
+	case nil:
+		break
+	case config.ConfigNotFoundErr:
+		fmt.Println(
+			"Please ensure that a config file is specified with the --config flag or " +
+				"is present at one of the following locations:\n" +
+				"\t- ./anchore-ecs-inventory.yaml\n" +
+				"\t- ./.anchore-ecs-inventory/config.yaml\n" +
+				"\t- $HOME/anchore-ecs-inventory.yaml\n" +
+				"\t- $XDG_CONFIG_HOME/anchore-ecs-inventory/config.yaml")
+		os.Exit(1)
+	default:
+		fmt.Printf("Failed to load application config: \n\t%+v\n", err)
 		os.Exit(1)
 	}
+
 	appConfig = cfg
 }
 

internal/config/config.go

@@ -62,6 +62,8 @@ var DefaultConfigValues = AppConfig{
 	PollingIntervalSeconds: 300,
 }
 
+var ConfigNotFoundErr error = fmt.Errorf("application config not found")
+
 func setDefaultValues(v *viper.Viper) {
 	v.SetDefault("log.level", DefaultConfigValues.Log.Level)
 	v.SetDefault("log.file", DefaultConfigValues.Log.FileLocation)
@@ -174,7 +176,7 @@ func readConfig(v *viper.Viper, configPath, applicationName string) error {
 		return nil
 	}
 
-	return fmt.Errorf("application config not found")
+	return ConfigNotFoundErr
 }
 
 func (cfg AppConfig) String() string {