Method validateYAMLEmptyNodes

pkg/cortex/cortex.go:272–293

validateYAMLEmptyNodes ensure that no empty node has been specified in the YAML config file. When an empty node is defined in YAML, the YAML parser sets the whole struct to its zero value and so we loose all default values. It's very difficult to detect this case for the user, so we try to prevent i

()

// and so we loose all default values. It's very difficult to detect this case for the user, so we
// try to prevent it (on the root level) with this custom validation.
func (c *Config) validateYAMLEmptyNodes() error {
	defaults := Config{}
	flagext.DefaultValues(&defaults)

	defStruct := reflect.ValueOf(defaults)
	cfgStruct := reflect.ValueOf(*c)

	// We expect all structs are the exact same. This check should never fail.
	if cfgStruct.NumField() != defStruct.NumField() {
		return errors.New("unable to validate configuration because of mismatching internal config data structure")
	}

	for i := 0; i < cfgStruct.NumField(); i++ {
		// If the struct has been reset due to empty YAML value and the zero struct value
		// doesn't match the default one, then we should warn the user about the issue.
		if cfgStruct.Field(i).Kind() == reflect.Struct && cfgStruct.Field(i).IsZero() && !defStruct.Field(i).IsZero() {
			return fmt.Errorf("the %s configuration in YAML has been specified as an empty YAML node", cfgStruct.Type().Field(i).Name)
		}
	}

	return nil
}

func (c *Config) registerServerFlagsWithChangedDefaultValues(fs *flag.FlagSet) {
	throwaway := flag.NewFlagSet("throwaway", flag.PanicOnError)