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unmarshal-notifier.go
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unmarshal-notifier.go
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package notifiers
import (
"fmt"
"github.com/fluxninja/aperture/v2/pkg/config"
"github.com/fluxninja/aperture/v2/pkg/log"
)
// UnmarshalNotifyFunc is a function that is called when a config key is written.
type UnmarshalNotifyFunc func(Event, config.Unmarshaller)
// GetUnmarshallerFunc is a function that is called to create a new unmarshaller.
type GetUnmarshallerFunc func(bytes []byte) (config.Unmarshaller, error)
// unmarshalKeyNotifier holds the state of a key notifier that updates config at a key using the provided unmarshaller.
type unmarshalKeyNotifier struct {
Unmarshaller config.Unmarshaller
UnmarshalNotifyFunc UnmarshalNotifyFunc
KeyBase
}
// Make sure ConfigKeyNotifier implements KeyNotifier.
var _ KeyNotifier = (*unmarshalKeyNotifier)(nil)
// NewUnmarshalKeyNotifier creates a new instance of ConfigKeyNotifier.
func NewUnmarshalKeyNotifier(key Key,
unmarshaller config.Unmarshaller,
unmarshalNotifyFunc UnmarshalNotifyFunc,
) (*unmarshalKeyNotifier, error) {
return &unmarshalKeyNotifier{
KeyBase: NewKeyBase(key),
Unmarshaller: unmarshaller,
UnmarshalNotifyFunc: unmarshalNotifyFunc,
}, nil
}
// Notify provides an unmarshaller based on received event.
// It reloads the the bytes into unmarshaller before invoking callback.
func (ukn *unmarshalKeyNotifier) Notify(event Event) {
if ukn.Unmarshaller != nil {
// Only update unmarshaller on write
if event.Type == Write {
log.Trace().Str("key", event.Key.String()).Msg("write event")
// read config via unmarshaller
err := ukn.Unmarshaller.Reload(event.Value)
if err != nil {
log.Error().Err(err).Str("key", event.Key.String()).Msg("error reading")
return
}
}
if ukn.UnmarshalNotifyFunc != nil {
// notify
ukn.UnmarshalNotifyFunc(event, ukn.Unmarshaller)
}
}
}
// unmarshalPrefixNotifier holds the state of a prefix notifier that updates config at a prefix using the provided unmarshaller.
type unmarshalPrefixNotifier struct {
unmarshalNotifyFunc UnmarshalNotifyFunc
getUnmarshallerFunc GetUnmarshallerFunc
PrefixBase
}
// Make sure UnmarshalPrefixNotifier implements PrefixNotifier.
var _ PrefixNotifier = (*unmarshalPrefixNotifier)(nil)
// GetKeyNotifier returns a new key notifier for the given key.
func (upn *unmarshalPrefixNotifier) GetKeyNotifier(key Key) (KeyNotifier, error) {
// create a new unmarshaller instance
unmarshaller, err := upn.getUnmarshallerFunc(nil)
if err != nil {
return nil, err
}
return NewUnmarshalKeyNotifier(key, unmarshaller, upn.unmarshalNotifyFunc)
}
// NewUnmarshalPrefixNotifier returns a new instance of UnmarshalPrefixNotifier.
func NewUnmarshalPrefixNotifier(prefix string,
unmarshalNotifyFunc UnmarshalNotifyFunc,
getUnmarshallerFunc GetUnmarshallerFunc,
) (*unmarshalPrefixNotifier, error) {
if getUnmarshallerFunc == nil {
return nil, fmt.Errorf("getUnmarshallerFunc cannot be nil")
}
notifier := &unmarshalPrefixNotifier{
PrefixBase: NewPrefixBase(prefix),
unmarshalNotifyFunc: unmarshalNotifyFunc,
getUnmarshallerFunc: getUnmarshallerFunc,
}
return notifier, nil
}