blob: 449daba3a9e4984fb2a5a53bb64630d5a127f0ef [file] [log] [blame]
// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cache
import (
var (
KeyCreateSession = NewSessionKey("create_session", "A new session was added")
KeyUpdateSession = NewSessionKey("update_session", "Updated information about a session")
KeyShutdownSession = NewSessionKey("shutdown_session", "A session was shut down")
// SessionKey represents an event label key that has a *Session value.
type SessionKey struct {
name string
description string
// NewSessionKey creates a new Key for *Session values.
func NewSessionKey(name, description string) *SessionKey {
return &SessionKey{name: name, description: description}
func (k *SessionKey) Name() string { return }
func (k *SessionKey) Description() string { return k.description }
func (k *SessionKey) Format(w io.Writer, buf []byte, l label.Label) {
io.WriteString(w, k.From(l).ID())
// Of creates a new Label with this key and the supplied session.
func (k *SessionKey) Of(v *Session) label.Label { return label.OfValue(k, v) }
// Get can be used to get the session for the key from a label.Map.
func (k *SessionKey) Get(lm label.Map) *Session {
if t := lm.Find(k); t.Valid() {
return k.From(t)
return nil
// From can be used to get the session value from a Label.
func (k *SessionKey) From(t label.Label) *Session {
err, _ := t.UnpackValue().(*Session)
return err