forgejo/modules/graceful/server_hooks.go

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// +build !windows
// 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 (
"errors"
"fmt"
"os"
"runtime"
"time"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
)
// shutdown closes the listener so that no new connections are accepted
// and starts a goroutine that will hammer (stop all running requests) the server
// after setting.GracefulHammerTime.
func (srv *Server) shutdown() {
// only shutdown if we're running.
if srv.getState() != stateRunning {
return
}
srv.setState(stateShuttingDown)
if setting.GracefulHammerTime >= 0 {
go srv.hammerTime(setting.GracefulHammerTime)
}
if srv.OnShutdown != nil {
srv.OnShutdown()
}
err := srv.listener.Close()
if err != nil {
log.Error("PID: %d Listener.Close() error: %v", os.Getpid(), err)
} else {
log.Info("PID: %d Listener (%s) closed.", os.Getpid(), srv.listener.Addr())
}
}
// hammerTime forces the server to shutdown in a given timeout - whether it
// finished outstanding requests or not. if Read/WriteTimeout are not set or the
// max header size is very big a connection could hang...
//
// srv.Serve() will not return until all connections are served. this will
// unblock the srv.wg.Wait() in Serve() thus causing ListenAndServe* functions to
// return.
func (srv *Server) hammerTime(d time.Duration) {
defer func() {
// We call srv.wg.Done() until it panics.
// This happens if we call Done() when the WaitGroup counter is already at 0
// So if it panics -> we're done, Serve() will return and the
// parent will goroutine will exit.
if r := recover(); r != nil {
log.Error("WaitGroup at 0: Error: %v", r)
}
}()
if srv.getState() != stateShuttingDown {
return
}
time.Sleep(d)
log.Warn("Forcefully shutting down parent")
for {
if srv.getState() == stateTerminate {
break
}
srv.wg.Done()
// Give other goroutines a chance to finish before we forcibly stop them.
runtime.Gosched()
}
}
func (srv *Server) fork() error {
runningServerReg.Lock()
defer runningServerReg.Unlock()
// only one server instance should fork!
if runningServersForked {
return errors.New("another process already forked. Ignoring this one")
}
runningServersForked = true
// We need to move the file logs to append pids
setting.RestartLogsWithPIDSuffix()
_, err := RestartProcess()
return err
}
// RegisterPreSignalHook registers a function to be run before the signal handler for
// a given signal. These are not mutex locked and should therefore be only called before Serve.
func (srv *Server) RegisterPreSignalHook(sig os.Signal, f func()) (err error) {
for _, s := range hookableSignals {
if s == sig {
srv.PreSignalHooks[sig] = append(srv.PreSignalHooks[sig], f)
return
}
}
err = fmt.Errorf("Signal %v is not supported", sig)
return
}
// RegisterPostSignalHook registers a function to be run after the signal handler for
// a given signal. These are not mutex locked and should therefore be only called before Serve.
func (srv *Server) RegisterPostSignalHook(sig os.Signal, f func()) (err error) {
for _, s := range hookableSignals {
if s == sig {
srv.PostSignalHooks[sig] = append(srv.PostSignalHooks[sig], f)
return
}
}
err = fmt.Errorf("Signal %v is not supported", sig)
return
}