forgejo/modules/graceful/manager.go

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// Copyright 2019 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package graceful
import (
"time"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
)
type state uint8
const (
stateInit state = iota
stateRunning
stateShuttingDown
stateTerminate
)
// There are three places that could inherit sockets:
//
// * HTTP or HTTPS main listener
// * HTTP redirection fallback
// * SSH
//
// If you add an additional place you must increment this number
// and add a function to call manager.InformCleanup if it's not going to be used
const numberOfServersToCreate = 3
// Manager represents the graceful server manager interface
var Manager *gracefulManager
func init() {
Manager = newGracefulManager()
}
func (g *gracefulManager) doShutdown() {
if !g.setStateTransition(stateRunning, stateShuttingDown) {
return
}
g.lock.Lock()
close(g.shutdown)
g.lock.Unlock()
if setting.GracefulHammerTime >= 0 {
go g.doHammerTime(setting.GracefulHammerTime)
}
go func() {
g.WaitForServers()
<-time.After(1 * time.Second)
g.doTerminate()
}()
}
func (g *gracefulManager) doHammerTime(d time.Duration) {
time.Sleep(d)
select {
case <-g.hammer:
default:
log.Warn("Setting Hammer condition")
close(g.hammer)
}
}
func (g *gracefulManager) doTerminate() {
if !g.setStateTransition(stateShuttingDown, stateTerminate) {
return
}
g.lock.Lock()
close(g.terminate)
g.lock.Unlock()
}
// IsChild returns if the current process is a child of previous Gitea process
func (g *gracefulManager) IsChild() bool {
return g.isChild
}
// IsShutdown returns a channel which will be closed at shutdown.
// The order of closure is IsShutdown, IsHammer (potentially), IsTerminate
func (g *gracefulManager) IsShutdown() <-chan struct{} {
g.lock.RLock()
if g.shutdown == nil {
g.lock.RUnlock()
g.lock.Lock()
if g.shutdown == nil {
g.shutdown = make(chan struct{})
}
defer g.lock.Unlock()
return g.shutdown
}
defer g.lock.RUnlock()
return g.shutdown
}
// IsHammer returns a channel which will be closed at hammer
// The order of closure is IsShutdown, IsHammer (potentially), IsTerminate
// Servers running within the running server wait group should respond to IsHammer
// if not shutdown already
func (g *gracefulManager) IsHammer() <-chan struct{} {
g.lock.RLock()
if g.hammer == nil {
g.lock.RUnlock()
g.lock.Lock()
if g.hammer == nil {
g.hammer = make(chan struct{})
}
defer g.lock.Unlock()
return g.hammer
}
defer g.lock.RUnlock()
return g.hammer
}
// IsTerminate returns a channel which will be closed at terminate
// The order of closure is IsShutdown, IsHammer (potentially), IsTerminate
// IsTerminate will only close once all running servers have stopped
func (g *gracefulManager) IsTerminate() <-chan struct{} {
g.lock.RLock()
if g.terminate == nil {
g.lock.RUnlock()
g.lock.Lock()
if g.terminate == nil {
g.terminate = make(chan struct{})
}
defer g.lock.Unlock()
return g.terminate
}
defer g.lock.RUnlock()
return g.terminate
}
// ServerDone declares a running server done and subtracts one from the
// running server wait group. Users probably do not want to call this
// and should use one of the RunWithShutdown* functions
func (g *gracefulManager) ServerDone() {
g.runningServerWaitGroup.Done()
}
// WaitForServers waits for all running servers to finish. Users should probably
// instead use AtTerminate or IsTerminate
func (g *gracefulManager) WaitForServers() {
g.runningServerWaitGroup.Wait()
}
// WaitForTerminate waits for all terminating actions to finish.
// Only the main go-routine should use this
func (g *gracefulManager) WaitForTerminate() {
g.terminateWaitGroup.Wait()
}
func (g *gracefulManager) getState() state {
g.lock.RLock()
defer g.lock.RUnlock()
return g.state
}
func (g *gracefulManager) setStateTransition(old, new state) bool {
if old != g.getState() {
return false
}
g.lock.Lock()
if g.state != old {
g.lock.Unlock()
return false
}
g.state = new
g.lock.Unlock()
return true
}
func (g *gracefulManager) setState(st state) {
g.lock.Lock()
defer g.lock.Unlock()
g.state = st
}
// InformCleanup tells the cleanup wait group that we have either taken a listener
// or will not be taking a listener
func (g *gracefulManager) InformCleanup() {
g.createServerWaitGroup.Done()
}