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gitea/modules/graceful/manager_windows.go

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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.
// This code is heavily inspired by the archived gofacebook/gracenet/net.go handler
//go:build windows
// +build windows
package graceful
import (
"context"
"os"
"strconv"
"sync"
"time"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"golang.org/x/sys/windows/svc"
"golang.org/x/sys/windows/svc/debug"
)
// WindowsServiceName is the name of the Windows service
var WindowsServiceName = "gitea"
const (
hammerCode = 128
hammerCmd = svc.Cmd(hammerCode)
acceptHammerCode = svc.Accepted(hammerCode)
)
// Manager manages the graceful shutdown process
type Manager struct {
ctx context.Context
isChild bool
lock *sync.RWMutex
state state
shutdownCtx context.Context
hammerCtx context.Context
terminateCtx context.Context
doneCtx context.Context
shutdownCtxCancel context.CancelFunc
hammerCtxCancel context.CancelFunc
terminateCtxCancel context.CancelFunc
doneCtxCancel context.CancelFunc
runningServerWaitGroup sync.WaitGroup
createServerWaitGroup sync.WaitGroup
terminateWaitGroup sync.WaitGroup
shutdownRequested chan struct{}
toRunAtShutdown []func()
toRunAtHammer []func()
toRunAtTerminate []func()
}
func newGracefulManager(ctx context.Context) *Manager {
manager := &Manager{
isChild: false,
lock: &sync.RWMutex{},
ctx: ctx,
}
manager.createServerWaitGroup.Add(numberOfServersToCreate)
manager.start()
return manager
}
func (g *Manager) start() {
// Make contexts
g.terminateCtx, g.terminateCtxCancel = context.WithCancel(g.ctx)
g.shutdownCtx, g.shutdownCtxCancel = context.WithCancel(g.ctx)
g.hammerCtx, g.hammerCtxCancel = context.WithCancel(g.ctx)
g.doneCtx, g.doneCtxCancel = context.WithCancel(g.ctx)
// Make channels
g.shutdownRequested = make(chan struct{})
// Set the running state
g.setState(stateRunning)
if skip, _ := strconv.ParseBool(os.Getenv("SKIP_MINWINSVC")); skip {
log.Trace("Skipping SVC check as SKIP_MINWINSVC is set")
return
}
// Make SVC process
run := svc.Run
//lint:ignore SA1019 We use IsAnInteractiveSession because IsWindowsService has a different permissions profile
isAnInteractiveSession, err := svc.IsAnInteractiveSession()
if err != nil {
log.Error("Unable to ascertain if running as an Windows Service: %v", err)
return
}
if isAnInteractiveSession {
log.Trace("Not running a service ... using the debug SVC manager")
run = debug.Run
}
go func() {
_ = run(WindowsServiceName, g)
}()
}
// Execute makes Manager implement svc.Handler
func (g *Manager) Execute(args []string, changes <-chan svc.ChangeRequest, status chan<- svc.Status) (svcSpecificEC bool, exitCode uint32) {
if setting.StartupTimeout > 0 {
status <- svc.Status{State: svc.StartPending}
} else {
status <- svc.Status{State: svc.StartPending, WaitHint: uint32(setting.StartupTimeout / time.Millisecond)}
}
log.Trace("Awaiting server start-up")
// Now need to wait for everything to start...
if !g.awaitServer(setting.StartupTimeout) {
log.Trace("... start-up failed ... Stopped")
return false, 1
}
log.Trace("Sending Running state to SVC")
// We need to implement some way of svc.AcceptParamChange/svc.ParamChange
status <- svc.Status{
State: svc.Running,
Accepts: svc.AcceptStop | svc.AcceptShutdown | acceptHammerCode,
}
log.Trace("Started")
waitTime := 30 * time.Second
loop:
for {
select {
case <-g.ctx.Done():
log.Trace("Shutting down")
g.DoGracefulShutdown()
waitTime += setting.GracefulHammerTime
break loop
case <-g.shutdownRequested:
log.Trace("Shutting down")
waitTime += setting.GracefulHammerTime
break loop
case change := <-changes:
switch change.Cmd {
case svc.Interrogate:
log.Trace("SVC sent interrogate")
status <- change.CurrentStatus
case svc.Stop, svc.Shutdown:
log.Trace("SVC requested shutdown - shutting down")
g.DoGracefulShutdown()
waitTime += setting.GracefulHammerTime
break loop
case hammerCode:
log.Trace("SVC requested hammer - shutting down and hammering immediately")
g.DoGracefulShutdown()
g.DoImmediateHammer()
break loop
default:
log.Debug("Unexpected control request: %v", change.Cmd)
}
}
}
log.Trace("Sending StopPending state to SVC")
status <- svc.Status{
State: svc.StopPending,
WaitHint: uint32(waitTime / time.Millisecond),
}
hammerLoop:
for {
select {
case change := <-changes:
switch change.Cmd {
case svc.Interrogate:
log.Trace("SVC sent interrogate")
status <- change.CurrentStatus
case svc.Stop, svc.Shutdown, hammerCmd:
log.Trace("SVC requested hammer - hammering immediately")
g.DoImmediateHammer()
break hammerLoop
default:
log.Debug("Unexpected control request: %v", change.Cmd)
}
case <-g.hammerCtx.Done():
break hammerLoop
}
}
log.Trace("Stopped")
return false, 0
}
// DoImmediateHammer causes an immediate hammer
func (g *Manager) DoImmediateHammer() {
g.doHammerTime(0 * time.Second)
}
// DoGracefulShutdown causes a graceful shutdown
func (g *Manager) DoGracefulShutdown() {
g.lock.Lock()
select {
case <-g.shutdownRequested:
g.lock.Unlock()
default:
close(g.shutdownRequested)
g.lock.Unlock()
g.doShutdown()
}
}
// RegisterServer registers the running of a listening server.
// Any call to RegisterServer must be matched by a call to ServerDone
func (g *Manager) RegisterServer() {
g.runningServerWaitGroup.Add(1)
}
func (g *Manager) awaitServer(limit time.Duration) bool {
c := make(chan struct{})
go func() {
defer close(c)
g.createServerWaitGroup.Wait()
}()
if limit > 0 {
select {
case <-c:
return true // completed normally
case <-time.After(limit):
return false // timed out
case <-g.IsShutdown():
return false
}
} else {
select {
case <-c:
return true // completed normally
case <-g.IsShutdown():
return false
}
}
}