forgejo/modules/graceful/manager_common.go

108 lines
3.3 KiB
Go

// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package graceful
import (
"context"
"runtime/pprof"
"sync"
"time"
)
// FIXME: it seems that there is a bug when using systemd Type=notify: the "Install Page" (INSTALL_LOCK=false) doesn't notify properly.
// At the moment, no idea whether it also affects Windows Service, or whether it's a regression bug. It needs to be investigated later.
type systemdNotifyMsg string
const (
readyMsg systemdNotifyMsg = "READY=1"
stoppingMsg systemdNotifyMsg = "STOPPING=1"
reloadingMsg systemdNotifyMsg = "RELOADING=1"
watchdogMsg systemdNotifyMsg = "WATCHDOG=1"
)
func statusMsg(msg string) systemdNotifyMsg {
return systemdNotifyMsg("STATUS=" + msg)
}
// Manager manages the graceful shutdown process
type Manager struct {
ctx context.Context
isChild bool
forked bool
lock sync.RWMutex
state state
shutdownCtx context.Context
hammerCtx context.Context
terminateCtx context.Context
managerCtx context.Context
shutdownCtxCancel context.CancelFunc
hammerCtxCancel context.CancelFunc
terminateCtxCancel context.CancelFunc
managerCtxCancel context.CancelFunc
runningServerWaitGroup sync.WaitGroup
terminateWaitGroup sync.WaitGroup
createServerCond sync.Cond
createdServer int
shutdownRequested chan struct{}
toRunAtShutdown []func()
toRunAtTerminate []func()
}
func newGracefulManager(ctx context.Context) *Manager {
manager := &Manager{ctx: ctx, shutdownRequested: make(chan struct{})}
manager.createServerCond.L = &sync.Mutex{}
manager.prepare(ctx)
manager.start()
return manager
}
func (g *Manager) prepare(ctx context.Context) {
g.terminateCtx, g.terminateCtxCancel = context.WithCancel(ctx)
g.shutdownCtx, g.shutdownCtxCancel = context.WithCancel(ctx)
g.hammerCtx, g.hammerCtxCancel = context.WithCancel(ctx)
g.managerCtx, g.managerCtxCancel = context.WithCancel(ctx)
g.terminateCtx = pprof.WithLabels(g.terminateCtx, pprof.Labels("gracefulLifecycle", "with-terminate"))
g.shutdownCtx = pprof.WithLabels(g.shutdownCtx, pprof.Labels("gracefulLifecycle", "with-shutdown"))
g.hammerCtx = pprof.WithLabels(g.hammerCtx, pprof.Labels("gracefulLifecycle", "with-hammer"))
g.managerCtx = pprof.WithLabels(g.managerCtx, pprof.Labels("gracefulLifecycle", "with-manager"))
if !g.setStateTransition(stateInit, stateRunning) {
panic("invalid graceful manager state: transition from init to running failed")
}
}
// DoImmediateHammer causes an immediate hammer
func (g *Manager) DoImmediateHammer() {
g.notify(statusMsg("Sending immediate hammer"))
g.doHammerTime(0 * time.Second)
}
// DoGracefulShutdown causes a graceful shutdown
func (g *Manager) DoGracefulShutdown() {
g.lock.Lock()
select {
case <-g.shutdownRequested:
default:
close(g.shutdownRequested)
}
forked := g.forked
g.lock.Unlock()
if !forked {
g.notify(stoppingMsg)
} else {
g.notify(statusMsg("Shutting down after fork"))
}
g.doShutdown()
}
// RegisterServer registers the running of a listening server, in the case of unix this means that the parent process can now die.
// Any call to RegisterServer must be matched by a call to ServerDone
func (g *Manager) RegisterServer() {
KillParent()
g.runningServerWaitGroup.Add(1)
}