113 lines
2.7 KiB

package config
import (
yaml ""
// Notifier sends out config updates
type Notifier interface {
// Manager is the base functions of the config manager
type Manager interface {
Start(Notifier) error
// FileManager watches the yaml config for changes
// sends updates to the service to reconfigure to match the updated config
type FileManager struct {
watcher watcher.Notifier
notifier Notifier
configPath string
log *zerolog.Logger
ReadConfig func(string, *zerolog.Logger) (Root, error)
// NewFileManager creates a config manager
func NewFileManager(watcher watcher.Notifier, configPath string, log *zerolog.Logger) (*FileManager, error) {
m := &FileManager{
watcher: watcher,
configPath: configPath,
log: log,
ReadConfig: readConfigFromPath,
err := watcher.Add(configPath)
return m, err
// Start starts the runloop to watch for config changes
func (m *FileManager) Start(notifier Notifier) error {
m.notifier = notifier
// update the notifier with a fresh config on start
config, err := m.GetConfig()
if err != nil {
return err
return nil
// GetConfig reads the yaml file from the disk
func (m *FileManager) GetConfig() (Root, error) {
return m.ReadConfig(m.configPath, m.log)
// Shutdown stops the watcher
func (m *FileManager) Shutdown() {
func readConfigFromPath(configPath string, log *zerolog.Logger) (Root, error) {
if configPath == "" {
return Root{}, errors.New("unable to find config file")
file, err := os.Open(configPath)
if err != nil {
return Root{}, err
defer file.Close()
var config Root
if err := yaml.NewDecoder(file).Decode(&config); err != nil {
if err == io.EOF {
log.Error().Msgf("Configuration file %s was empty", configPath)
return Root{}, nil
return Root{}, errors.Wrap(err, "error parsing YAML in config file at "+configPath)
return config, nil
// File change notifications from the watcher
// WatcherItemDidChange triggers when the yaml config is updated
// sends the updated config to the service to reload its state
func (m *FileManager) WatcherItemDidChange(filepath string) {
config, err := m.GetConfig()
if err != nil {
m.log.Err(err).Msg("Failed to read new config")
m.log.Info().Msg("Config file has been updated")
// WatcherDidError notifies of errors with the file watcher
func (m *FileManager) WatcherDidError(err error) {
m.log.Err(err).Msg("Config watcher encountered an error")