forgejo/modules/graceful/manager.go
zeripath 60c5339042 Graceful: Cancel Process on monitor pages & HammerTime (#9213)
* Graceful: Create callbacks to with contexts

* Graceful: Say when Gitea is completely finished

* Graceful: Git and Process within HammerTime

Force all git commands to terminate at HammerTime
Force all process commands to terminate at HammerTime
Move almost all git processes to run as git Commands

* Graceful: Always Hammer after Shutdown

* ProcessManager: Add cancel functionality

* Fix tests

* Make sure that process.Manager.Kill() cancels

* Make threadsafe access to Processes and remove own unused Kill

* Remove cmd from the process manager as it is no longer used

* the default context is the correct context

* get rid of double till
2019-11-30 16:40:22 +02:00

293 lines
9.2 KiB
Go

// 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 (
"context"
"time"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/process"
"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(context.Background())
// Set the git default context to the HammerContext
git.DefaultContext = Manager.HammerContext()
// Set the process default context to the HammerContext
process.DefaultContext = Manager.HammerContext()
}
// CallbackWithContext is combined runnable and context to watch to see if the caller has finished
type CallbackWithContext func(ctx context.Context, callback func())
// RunnableWithShutdownFns is a runnable with functions to run at shutdown and terminate
// After the callback to atShutdown is called and is complete, the main function must return.
// Similarly the callback function provided to atTerminate must return once termination is complete.
// Please note that use of the atShutdown and atTerminate callbacks will create go-routines that will wait till their respective signals
// - users must therefore be careful to only call these as necessary.
// If run is not expected to run indefinitely RunWithShutdownChan is likely to be more appropriate.
type RunnableWithShutdownFns func(atShutdown, atTerminate func(context.Context, func()))
// RunWithShutdownFns takes a function that has both atShutdown and atTerminate callbacks
// After the callback to atShutdown is called and is complete, the main function must return.
// Similarly the callback function provided to atTerminate must return once termination is complete.
// Please note that use of the atShutdown and atTerminate callbacks will create go-routines that will wait till their respective signals
// - users must therefore be careful to only call these as necessary.
// If run is not expected to run indefinitely RunWithShutdownChan is likely to be more appropriate.
func (g *gracefulManager) RunWithShutdownFns(run RunnableWithShutdownFns) {
g.runningServerWaitGroup.Add(1)
defer g.runningServerWaitGroup.Done()
run(func(ctx context.Context, atShutdown func()) {
go func() {
select {
case <-g.IsShutdown():
atShutdown()
case <-ctx.Done():
return
}
}()
}, func(ctx context.Context, atTerminate func()) {
g.RunAtTerminate(ctx, atTerminate)
})
}
// RunnableWithShutdownChan is a runnable with functions to run at shutdown and terminate.
// After the atShutdown channel is closed, the main function must return once shutdown is complete.
// (Optionally IsHammer may be waited for instead however, this should be avoided if possible.)
// The callback function provided to atTerminate must return once termination is complete.
// Please note that use of the atTerminate function will create a go-routine that will wait till terminate - users must therefore be careful to only call this as necessary.
type RunnableWithShutdownChan func(atShutdown <-chan struct{}, atTerminate CallbackWithContext)
// RunWithShutdownChan takes a function that has channel to watch for shutdown and atTerminate callbacks
// After the atShutdown channel is closed, the main function must return once shutdown is complete.
// (Optionally IsHammer may be waited for instead however, this should be avoided if possible.)
// The callback function provided to atTerminate must return once termination is complete.
// Please note that use of the atTerminate function will create a go-routine that will wait till terminate - users must therefore be careful to only call this as necessary.
func (g *gracefulManager) RunWithShutdownChan(run RunnableWithShutdownChan) {
g.runningServerWaitGroup.Add(1)
defer g.runningServerWaitGroup.Done()
run(g.IsShutdown(), func(ctx context.Context, atTerminate func()) {
g.RunAtTerminate(ctx, atTerminate)
})
}
// RunWithShutdownContext takes a function that has a context to watch for shutdown.
// After the provided context is Done(), the main function must return once shutdown is complete.
// (Optionally the HammerContext may be obtained and waited for however, this should be avoided if possible.)
func (g *gracefulManager) RunWithShutdownContext(run func(context.Context)) {
g.runningServerWaitGroup.Add(1)
defer g.runningServerWaitGroup.Done()
run(g.ShutdownContext())
}
// RunAtTerminate adds to the terminate wait group and creates a go-routine to run the provided function at termination
func (g *gracefulManager) RunAtTerminate(ctx context.Context, terminate func()) {
g.terminateWaitGroup.Add(1)
go func() {
select {
case <-g.IsTerminate():
terminate()
case <-ctx.Done():
}
g.terminateWaitGroup.Done()
}()
}
// RunAtShutdown creates a go-routine to run the provided function at shutdown
func (g *gracefulManager) RunAtShutdown(ctx context.Context, shutdown func()) {
go func() {
select {
case <-g.IsShutdown():
shutdown()
case <-ctx.Done():
}
}()
}
// RunAtHammer creates a go-routine to run the provided function at shutdown
func (g *gracefulManager) RunAtHammer(ctx context.Context, hammer func()) {
go func() {
select {
case <-g.IsHammer():
hammer()
case <-ctx.Done():
}
}()
}
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()
// Mop up any remaining unclosed events.
g.doHammerTime(0)
<-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()
}