beego suppot graceful restart application

@@ -19,9 +19,11 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
+	"os"
 	"text/template"
 	"time"
 
+	"github.com/astaxie/beego/grace"
 	"github.com/astaxie/beego/toolbox"
 	"github.com/astaxie/beego/utils"
 )
@@ -458,8 +460,14 @@ func (admin *adminApp) Run() {
 		http.Handle(p, f)
 	}
 	BeeLogger.Info("Admin server Running on %s", addr)
-	err := http.ListenAndServe(addr, nil)
+
+	var err error
+	if Graceful {
+		err = grace.ListenAndServe(addr, nil)
+	} else {
+		err = http.ListenAndServe(addr, nil)
+	}
 	if err != nil {
-		BeeLogger.Critical("Admin ListenAndServe: ", err)
+		BeeLogger.Critical("Admin ListenAndServe: ", err, fmt.Sprint(os.Getpid()))
 	}
 }

@@ -22,6 +22,7 @@ import (
 	"os"
 	"time"
 
+	"github.com/astaxie/beego/grace"
 	"github.com/astaxie/beego/utils"
 )
 
@@ -76,6 +77,41 @@ func (app *App) Run() {
 			err = fcgi.Serve(l, app.Handlers)
 		}
 	} else {
+		if Graceful {
+			if EnableHttpTLS {
+				go func() {
+					time.Sleep(20 * time.Microsecond)
+					if HttpsPort != 0 {
+						addr = fmt.Sprintf("%s:%d", HttpAddr, HttpsPort)
+					}
+					server := grace.NewServer(addr, app.Handlers)
+					server.Server.ReadTimeout = time.Duration(HttpServerTimeOut) * time.Second
+					server.Server.WriteTimeout = time.Duration(HttpServerTimeOut) * time.Second
+					err := server.ListenAndServeTLS(HttpCertFile, HttpKeyFile)
+					if err != nil {
+						BeeLogger.Critical("ListenAndServeTLS: ", err)
+						time.Sleep(100 * time.Microsecond)
+						endRunning <- true
+					}
+				}()
+			}
+			if EnableHttpListen {
+				go func() {
+					server := grace.NewServer(addr, app.Handlers)
+					server.Server.ReadTimeout = time.Duration(HttpServerTimeOut) * time.Second
+					server.Server.WriteTimeout = time.Duration(HttpServerTimeOut) * time.Second
+					if ListenTCP4 && HttpAddr == "" {
+						server.Network = "tcp4"
+					}
+					err := server.ListenAndServe()
+					if err != nil {
+						BeeLogger.Critical("ListenAndServe: ", err, fmt.Sprint(os.Getpid()))
+						time.Sleep(100 * time.Microsecond)
+						endRunning <- true
+					}
+				}()
+			}
+		} else {
 			app.Server.Addr = addr
 			app.Server.Handler = app.Handlers
 			app.Server.ReadTimeout = time.Duration(HttpServerTimeOut) * time.Second
@@ -128,5 +164,6 @@ func (app *App) Run() {
 			}
 		}
 
+	}
 	<-endRunning
 }

@@ -82,6 +82,7 @@ var (
 	EnableDocs             bool   // enable generate docs & server docs API Swagger
 	RouterCaseSensitive    bool   // router case sensitive default is true
 	AccessLogs             bool   // print access logs, default is false
+	Graceful               bool   // use graceful start the server
 )
 
 type beegoAppConfig struct {
@@ -509,5 +510,8 @@ func ParseConfig() (err error) {
 	if casesensitive, err := AppConfig.Bool("RouterCaseSensitive"); err == nil {
 		RouterCaseSensitive = casesensitive
 	}
+	if graceful, err := AppConfig.Bool("Graceful"); err == nil {
+		Graceful = graceful
+	}
 	return nil
 }

+// Copyright 2014 beego Author. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Description: http://grisha.org/blog/2014/06/03/graceful-restart-in-golang/
+//
+// Usage:
+//
+// import(
+//   "log"
+//	 "net/http"
+//	 "os"
+//
+//   "github.com/astaxie/beego/grace"
+// )
+//
+//  func handler(w http.ResponseWriter, r *http.Request) {
+//	  w.Write([]byte("WORLD!"))
+//  }
+//
+//  func main() {
+//      mux := http.NewServeMux()
+//      mux.HandleFunc("/hello", handler)
+//
+//	    err := grace.ListenAndServe("localhost:8080", mux1)
+//      if err != nil {
+//		   log.Println(err)
+//	    }
+//      log.Println("Server on 8080 stopped")
+//	     os.Exit(0)
+//    }
+package grace
+
+import (
+	"crypto/tls"
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"os/exec"
+	"os/signal"
+	"strings"
+	"sync"
+	"syscall"
+	"time"
+)
+
+const (
+	PRE_SIGNAL = iota
+	POST_SIGNAL
+
+	STATE_INIT
+	STATE_RUNNING
+	STATE_SHUTTING_DOWN
+	STATE_TERMINATE
+)
+
+var (
+	regLock              *sync.Mutex
+	runningServers       map[string]*graceServer
+	runningServersOrder  []string
+	socketPtrOffsetMap   map[string]uint
+	runningServersForked bool
+
+	DefaultReadTimeOut    time.Duration
+	DefaultWriteTimeOut   time.Duration
+	DefaultMaxHeaderBytes int
+	DefaultTimeout        time.Duration
+
+	isChild     bool
+	socketOrder string
+)
+
+func init() {
+	regLock = &sync.Mutex{}
+	flag.BoolVar(&isChild, "graceful", false, "listen on open fd (after forking)")
+	flag.StringVar(&socketOrder, "socketorder", "", "previous initialization order - used when more than one listener was started")
+	runningServers = make(map[string]*graceServer)
+	runningServersOrder = []string{}
+	socketPtrOffsetMap = make(map[string]uint)
+
+	DefaultMaxHeaderBytes = 0
+
+	// after a restart the parent will finish ongoing requests before
+	// shutting down. set to a negative value to disable
+	DefaultTimeout = 60 * time.Second
+}
+
+type graceServer struct {
+	http.Server
+	GraceListener    net.Listener
+	SignalHooks      map[int]map[os.Signal][]func()
+	tlsInnerListener *graceListener
+	wg               sync.WaitGroup
+	sigChan          chan os.Signal
+	isChild          bool
+	state            uint8
+	Network          string
+}
+
+// NewServer returns an intialized graceServer. Calling Serve on it will
+// actually "start" the server.
+func NewServer(addr string, handler http.Handler) (srv *graceServer) {
+	regLock.Lock()
+	defer regLock.Unlock()
+	if !flag.Parsed() {
+		flag.Parse()
+	}
+	if len(socketOrder) > 0 {
+		for i, addr := range strings.Split(socketOrder, ",") {
+			socketPtrOffsetMap[addr] = uint(i)
+		}
+	} else {
+		socketPtrOffsetMap[addr] = uint(len(runningServersOrder))
+	}
+
+	srv = &graceServer{
+		wg:      sync.WaitGroup{},
+		sigChan: make(chan os.Signal),
+		isChild: isChild,
+		SignalHooks: map[int]map[os.Signal][]func(){
+			PRE_SIGNAL: map[os.Signal][]func(){
+				syscall.SIGHUP:  []func(){},
+				syscall.SIGUSR1: []func(){},
+				syscall.SIGUSR2: []func(){},
+				syscall.SIGINT:  []func(){},
+				syscall.SIGTERM: []func(){},
+				syscall.SIGTSTP: []func(){},
+			},
+			POST_SIGNAL: map[os.Signal][]func(){
+				syscall.SIGHUP:  []func(){},
+				syscall.SIGUSR1: []func(){},
+				syscall.SIGUSR2: []func(){},
+				syscall.SIGINT:  []func(){},
+				syscall.SIGTERM: []func(){},
+				syscall.SIGTSTP: []func(){},
+			},
+		},
+		state:   STATE_INIT,
+		Network: "tcp",
+	}
+
+	srv.Server.Addr = addr
+	srv.Server.ReadTimeout = DefaultReadTimeOut
+	srv.Server.WriteTimeout = DefaultWriteTimeOut
+	srv.Server.MaxHeaderBytes = DefaultMaxHeaderBytes
+	srv.Server.Handler = handler
+
+	runningServersOrder = append(runningServersOrder, addr)
+	runningServers[addr] = srv
+
+	return
+}
+
+// ListenAndServe listens on the TCP network address addr
+// and then calls Serve to handle requests on incoming connections.
+func ListenAndServe(addr string, handler http.Handler) error {
+	server := NewServer(addr, handler)
+	return server.ListenAndServe()
+}
+
+// ListenAndServeTLS listens on the TCP network address addr and then calls
+// Serve to handle requests on incoming TLS connections.
+//
+// Filenames containing a certificate and matching private key for the server must be provided.
+// If the certificate is signed by a certificate authority,
+// the certFile should be the concatenation of the server's certificate followed by the CA's certificate.
+func ListenAndServeTLS(addr string, certFile string, keyFile string, handler http.Handler) error {
+	server := NewServer(addr, handler)
+	return server.ListenAndServeTLS(certFile, keyFile)
+}
+
+// Serve accepts incoming connections on the Listener l,
+// creating a new service goroutine for each.
+// The service goroutines read requests and then call srv.Handler to reply to them.
+func (srv *graceServer) Serve() (err error) {
+	srv.state = STATE_RUNNING
+	err = srv.Server.Serve(srv.GraceListener)
+	log.Println(syscall.Getpid(), "Waiting for connections to finish...")
+	srv.wg.Wait()
+	srv.state = STATE_TERMINATE
+	return
+}
+
+// ListenAndServe listens on the TCP network address srv.Addr and then calls Serve
+// to handle requests on incoming connections. If srv.Addr is blank, ":http" is
+// used.
+func (srv *graceServer) ListenAndServe() (err error) {
+	addr := srv.Addr
+	if addr == "" {
+		addr = ":http"
+	}
+
+	go srv.handleSignals()
+
+	l, err := srv.getListener(addr)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	srv.GraceListener = newGraceListener(l, srv)
+
+	if srv.isChild {
+		syscall.Kill(syscall.Getppid(), syscall.SIGTERM)
+	}
+
+	log.Println(syscall.Getpid(), srv.Addr)
+	return srv.Serve()
+}
+
+// ListenAndServeTLS listens on the TCP network address srv.Addr and then calls
+// Serve to handle requests on incoming TLS connections.
+//
+// Filenames containing a certificate and matching private key for the server must
+// be provided. If the certificate is signed by a certificate authority, the
+// certFile should be the concatenation of the server's certificate followed by the
+// CA's certificate.
+//
+// If srv.Addr is blank, ":https" is used.
+func (srv *graceServer) ListenAndServeTLS(certFile, keyFile string) (err error) {
+	addr := srv.Addr
+	if addr == "" {
+		addr = ":https"
+	}
+
+	config := &tls.Config{}
+	if srv.TLSConfig != nil {
+		*config = *srv.TLSConfig
+	}
+	if config.NextProtos == nil {
+		config.NextProtos = []string{"http/1.1"}
+	}
+
+	config.Certificates = make([]tls.Certificate, 1)
+	config.Certificates[0], err = tls.LoadX509KeyPair(certFile, keyFile)
+	if err != nil {
+		return
+	}
+
+	go srv.handleSignals()
+
+	l, err := srv.getListener(addr)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	srv.tlsInnerListener = newGraceListener(l, srv)
+	srv.GraceListener = tls.NewListener(srv.tlsInnerListener, config)
+
+	if srv.isChild {
+		syscall.Kill(syscall.Getppid(), syscall.SIGTERM)
+	}
+
+	log.Println(syscall.Getpid(), srv.Addr)
+	return srv.Serve()
+}
+
+// getListener either opens a new socket to listen on, or takes the acceptor socket
+// it got passed when restarted.
+func (srv *graceServer) getListener(laddr string) (l net.Listener, err error) {
+	if srv.isChild {
+		var ptrOffset uint = 0
+		if len(socketPtrOffsetMap) > 0 {
+			ptrOffset = socketPtrOffsetMap[laddr]
+			log.Println("laddr", laddr, "ptr offset", socketPtrOffsetMap[laddr])
+		}
+
+		f := os.NewFile(uintptr(3+ptrOffset), "")
+		l, err = net.FileListener(f)
+		if err != nil {
+			err = fmt.Errorf("net.FileListener error: %v", err)
+			return
+		}
+	} else {
+		l, err = net.Listen(srv.Network, laddr)
+		if err != nil {
+			err = fmt.Errorf("net.Listen error: %v", err)
+			return
+		}
+	}
+	return
+}
+
+// handleSignals listens for os Signals and calls any hooked in function that the
+// user had registered with the signal.
+func (srv *graceServer) handleSignals() {
+	var sig os.Signal
+
+	signal.Notify(
+		srv.sigChan,
+		syscall.SIGHUP,
+		syscall.SIGUSR1,
+		syscall.SIGUSR2,
+		syscall.SIGINT,
+		syscall.SIGTERM,
+		syscall.SIGTSTP,
+	)
+
+	pid := syscall.Getpid()
+	for {
+		sig = <-srv.sigChan
+		srv.signalHooks(PRE_SIGNAL, sig)
+		switch sig {
+		case syscall.SIGHUP:
+			log.Println(pid, "Received SIGHUP. forking.")
+			err := srv.fork()
+			if err != nil {
+				log.Println("Fork err:", err)
+			}
+		case syscall.SIGUSR1:
+			log.Println(pid, "Received SIGUSR1.")
+		case syscall.SIGUSR2:
+			log.Println(pid, "Received SIGUSR2.")
+			srv.serverTimeout(0 * time.Second)
+		case syscall.SIGINT:
+			log.Println(pid, "Received SIGINT.")
+			srv.shutdown()
+		case syscall.SIGTERM:
+			log.Println(pid, "Received SIGTERM.")
+			srv.shutdown()
+		case syscall.SIGTSTP:
+			log.Println(pid, "Received SIGTSTP.")
+		default:
+			log.Printf("Received %v: nothing i care about...\n", sig)
+		}
+		srv.signalHooks(POST_SIGNAL, sig)
+	}
+}
+
+func (srv *graceServer) signalHooks(ppFlag int, sig os.Signal) {
+	if _, notSet := srv.SignalHooks[ppFlag][sig]; !notSet {
+		return
+	}
+	for _, f := range srv.SignalHooks[ppFlag][sig] {
+		f()
+	}
+	return
+}
+
+// shutdown closes the listener so that no new connections are accepted. it also
+// starts a goroutine that will hammer (stop all running requests) the server
+// after DefaultTimeout.
+func (srv *graceServer) shutdown() {
+	if srv.state != STATE_RUNNING {
+		return
+	}
+
+	srv.state = STATE_SHUTTING_DOWN
+	if DefaultTimeout >= 0 {
+		go srv.serverTimeout(DefaultTimeout)
+	}
+	err := srv.GraceListener.Close()
+	if err != nil {
+		log.Println(syscall.Getpid(), "Listener.Close() error:", err)
+	} else {
+		log.Println(syscall.Getpid(), srv.GraceListener.Addr(), "Listener closed.")
+	}
+}
+
+// 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(TLS) to
+// return.
+func (srv *graceServer) serverTimeout(d time.Duration) {
+	defer func() {
+		// we are calling srv.wg.Done() until it panics which means we called
+		// Done() when the counter was already at 0 and we're done.
+		// (and thus Serve() will return and the parent will exit)
+		if r := recover(); r != nil {
+			log.Println("WaitGroup at 0", r)
+		}
+	}()
+	if srv.state != STATE_SHUTTING_DOWN {
+		return
+	}
+	time.Sleep(d)
+	log.Println("[STOP - Hammer Time] Forcefully shutting down parent")
+	for {
+		if srv.state == STATE_TERMINATE {
+			break
+		}
+		srv.wg.Done()
+	}
+}
+
+func (srv *graceServer) fork() (err error) {
+	// only one server isntance should fork!
+	regLock.Lock()
+	defer regLock.Unlock()
+	if runningServersForked {
+		return
+	}
+	runningServersForked = true
+
+	var files = make([]*os.File, len(runningServers))
+	var orderArgs = make([]string, len(runningServers))
+	// get the accessor socket fds for _all_ server instances
+	for _, srvPtr := range runningServers {
+		// introspect.PrintTypeDump(srvPtr.EndlessListener)
+		switch srvPtr.GraceListener.(type) {
+		case *graceListener:
+			// normal listener
+			files[socketPtrOffsetMap[srvPtr.Server.Addr]] = srvPtr.GraceListener.(*graceListener).File()
+		default:
+			// tls listener
+			files[socketPtrOffsetMap[srvPtr.Server.Addr]] = srvPtr.tlsInnerListener.File()
+		}
+		orderArgs[socketPtrOffsetMap[srvPtr.Server.Addr]] = srvPtr.Server.Addr
+	}
+
+	log.Println(files)
+	path := os.Args[0]
+	var args []string
+	if len(os.Args) > 1 {
+		for _, arg := range os.Args[1:] {
+			if arg == "-graceful" {
+				break
+			}
+			args = append(args, arg)
+		}
+	}
+	args = append(args, "-graceful")
+	if len(runningServers) > 1 {
+		args = append(args, fmt.Sprintf(`-socketorder=%s`, strings.Join(orderArgs, ",")))
+		log.Println(args)
+	}
+	cmd := exec.Command(path, args...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	cmd.ExtraFiles = files
+	err = cmd.Start()
+	if err != nil {
+		log.Fatalf("Restart: Failed to launch, error: %v", err)
+	}
+
+	return
+}
+
+type graceListener struct {
+	net.Listener
+	stop    chan error
+	stopped bool
+	server  *graceServer
+}
+
+func (gl *graceListener) Accept() (c net.Conn, err error) {
+	tc, err := gl.Listener.(*net.TCPListener).AcceptTCP()
+	if err != nil {
+		return
+	}
+
+	tc.SetKeepAlive(true)                  // see http.tcpKeepAliveListener
+	tc.SetKeepAlivePeriod(3 * time.Minute) // see http.tcpKeepAliveListener
+
+	c = graceConn{
+		Conn:   tc,
+		server: gl.server,
+	}
+
+	gl.server.wg.Add(1)
+	return
+}
+
+func newGraceListener(l net.Listener, srv *graceServer) (el *graceListener) {
+	el = &graceListener{
+		Listener: l,
+		stop:     make(chan error),
+		server:   srv,
+	}
+
+	// Starting the listener for the stop signal here because Accept blocks on
+	// el.Listener.(*net.TCPListener).AcceptTCP()
+	// The goroutine will unblock it by closing the listeners fd
+	go func() {
+		_ = <-el.stop
+		el.stopped = true
+		el.stop <- el.Listener.Close()
+	}()
+	return
+}
+
+func (el *graceListener) Close() error {
+	if el.stopped {
+		return syscall.EINVAL
+	}
+	el.stop <- nil
+	return <-el.stop
+}
+
+func (el *graceListener) File() *os.File {
+	// returns a dup(2) - FD_CLOEXEC flag *not* set
+	tl := el.Listener.(*net.TCPListener)
+	fl, _ := tl.File()
+	return fl
+}
+
+type graceConn struct {
+	net.Conn
+	server *graceServer
+}
+
+func (c graceConn) Close() error {
+	c.server.wg.Done()
+	return c.Conn.Close()
+}