agent/config/config.go
func (cfg *Config) checkMissingAndDepreciated() error {
	cfgElem := reflect.ValueOf(cfg).Elem()
	cfgStructField := reflect.Indirect(reflect.ValueOf(cfg)).Type()

	fatalFields := []string{}
	for i := 0; i < cfgElem.NumField(); i++ {
		cfgField := cfgElem.Field(i)
		if utils.ZeroOrNil(cfgField.Interface()) {
			missingTag := cfgStructField.Field(i).Tag.Get("missing")
			if len(missingTag) == 0 {
				continue
			}
			switch missingTag {
			case "warn":
				seelog.Warnf("Configuration key not set, key: %v", cfgStructField.Field(i).Name)
			case "fatal":
				seelog.Criticalf("Configuration key not set, key: %v", cfgStructField.Field(i).Name)
				fatalFields = append(fatalFields, cfgStructField.Field(i).Name)
			default:
				seelog.Warnf("Unexpected `missing` tag value, tag %v", missingTag)
			}
		} else {
			// present
			deprecatedTag := cfgStructField.Field(i).Tag.Get("deprecated")
			if len(deprecatedTag) == 0 {
				continue
			}
			seelog.Warnf("Use of deprecated configuration key, key: %v message: %v", cfgStructField.Field(i).Name, deprecatedTag)
		}
	}
	if len(fatalFields) > 0 {
		return errors.New("Missing required fields: " + strings.Join(fatalFields, ", "))
	}
	return nil
}
func (cfg *Config) checkMissingAndDepreciated() error {
	cfgElem := reflect.ValueOf(cfg).Elem()
	cfgStructField := reflect.Indirect(reflect.ValueOf(cfg)).Type()

	fatalFields := []string{}
	for i := 0; i < cfgElem.NumField(); i++ {
		cfgField := cfgElem.Field(i)
		if utils.ZeroOrNil(cfgField.Interface()) {
			missingTag := cfgStructField.Field(i).Tag.Get("missing")
			if len(missingTag) == 0 {
				continue
			}
			switch missingTag {
			case "warn":
				seelog.Warnf("Configuration key not set, key: %v", cfgStructField.Field(i).Name)
			case "fatal":
				seelog.Criticalf("Configuration key not set, key: %v", cfgStructField.Field(i).Name)
				fatalFields = append(fatalFields, cfgStructField.Field(i).Name)
			default:
				seelog.Warnf("Unexpected `missing` tag value, tag %v", missingTag)
			}
		} else {
			// present
			deprecatedTag := cfgStructField.Field(i).Tag.Get("deprecated")
			if len(deprecatedTag) == 0 {
				continue
			}
			seelog.Warnf("Use of deprecated configuration key, key: %v message: %v", cfgStructField.Field(i).Name, deprecatedTag)
		}
	}
	if len(fatalFields) > 0 {
		return errors.New("Missing required fields: " + strings.Join(fatalFields, ", "))
	}
	return nil
}
// checkMissingAndDeprecated checks all zero-valued fields for tags of the form
// missing:STRING and acts based on that string. Current options are: fatal,
// warn. Fatal will result in an error being returned, warn will result in a
// warning that the field is missing being logged.