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forgejo/modules/eventsource/manager.go
Gusted 9c5c08859d
[BUG] Make logout event non-blocking
- When people click on the logout button, a event is sent to all
browser tabs (actually to a shared worker) to notify them of this
logout. This is done in a blocking fashion, to ensure every registered
channel (which realistically should be one for every user because of the
shared worker) for a user receives this message. While doing this, it
locks the mutex for the eventsource module.
- Codeberg is currently observing a deadlock that's caused by this
blocking behavior, a channel isn't receiving the logout event. We
currently don't have a good theory of why this is being caused. This in
turn is causing that the logout functionality is no longer working and
people no longer receive notifications, unless they refresh the page.
- This patchs makes this message non-blocking and thus making it
consistent with the other messages. We don't see a good reason why this
specific event needs to be blocking and the commit introducing it
doesn't offer a rationale either.
2024-08-12 19:13:23 +02:00

80 lines
1.6 KiB
Go

// Copyright 2020 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package eventsource
import (
"sync"
)
// Manager manages the eventsource Messengers
type Manager struct {
mutex sync.Mutex
messengers map[int64]*Messenger
connection chan struct{}
}
var manager *Manager
func init() {
manager = &Manager{
messengers: make(map[int64]*Messenger),
connection: make(chan struct{}, 1),
}
}
// GetManager returns a Manager and initializes one as singleton if there's none yet
func GetManager() *Manager {
return manager
}
// Register message channel
func (m *Manager) Register(uid int64) <-chan *Event {
m.mutex.Lock()
messenger, ok := m.messengers[uid]
if !ok {
messenger = NewMessenger(uid)
m.messengers[uid] = messenger
}
select {
case m.connection <- struct{}{}:
default:
}
m.mutex.Unlock()
return messenger.Register()
}
// Unregister message channel
func (m *Manager) Unregister(uid int64, channel <-chan *Event) {
m.mutex.Lock()
defer m.mutex.Unlock()
messenger, ok := m.messengers[uid]
if !ok {
return
}
if messenger.Unregister(channel) {
delete(m.messengers, uid)
}
}
// UnregisterAll message channels
func (m *Manager) UnregisterAll() {
m.mutex.Lock()
defer m.mutex.Unlock()
for _, messenger := range m.messengers {
messenger.UnregisterAll()
}
m.messengers = map[int64]*Messenger{}
}
// SendMessage sends a message to a particular user
func (m *Manager) SendMessage(uid int64, message *Event) {
m.mutex.Lock()
messenger, ok := m.messengers[uid]
m.mutex.Unlock()
if ok {
messenger.SendMessage(message)
}
}