forgejo/modules/graceful/server.go
2021-11-20 01:12:43 -05:00

262 lines
7 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.
// This code is highly inspired by endless go
package graceful
import (
"crypto/tls"
"net"
"os"
"strings"
"sync"
"sync/atomic"
"syscall"
"time"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
)
var (
// DefaultReadTimeOut default read timeout
DefaultReadTimeOut time.Duration
// DefaultWriteTimeOut default write timeout
DefaultWriteTimeOut time.Duration
// DefaultMaxHeaderBytes default max header bytes
DefaultMaxHeaderBytes int
// PerWriteWriteTimeout timeout for writes
PerWriteWriteTimeout = 30 * time.Second
// PerWriteWriteTimeoutKbTime is a timeout taking account of how much there is to be written
PerWriteWriteTimeoutKbTime = 10 * time.Second
)
func init() {
DefaultMaxHeaderBytes = 0 // use http.DefaultMaxHeaderBytes - which currently is 1 << 20 (1MB)
}
// ServeFunction represents a listen.Accept loop
type ServeFunction = func(net.Listener) error
// Server represents our graceful server
type Server struct {
network string
address string
listener net.Listener
wg sync.WaitGroup
state state
lock *sync.RWMutex
BeforeBegin func(network, address string)
OnShutdown func()
PerWriteTimeout time.Duration
PerWritePerKbTimeout time.Duration
}
// NewServer creates a server on network at provided address
func NewServer(network, address, name string) *Server {
if GetManager().IsChild() {
log.Info("Restarting new %s server: %s:%s on PID: %d", name, network, address, os.Getpid())
} else {
log.Info("Starting new %s server: %s:%s on PID: %d", name, network, address, os.Getpid())
}
srv := &Server{
wg: sync.WaitGroup{},
state: stateInit,
lock: &sync.RWMutex{},
network: network,
address: address,
PerWriteTimeout: setting.PerWriteTimeout,
PerWritePerKbTimeout: setting.PerWritePerKbTimeout,
}
srv.BeforeBegin = func(network, addr string) {
log.Debug("Starting server on %s:%s (PID: %d)", network, addr, syscall.Getpid())
}
return srv
}
// ListenAndServe listens on the provided network address and then calls Serve
// to handle requests on incoming connections.
func (srv *Server) ListenAndServe(serve ServeFunction) error {
go srv.awaitShutdown()
l, err := GetListener(srv.network, srv.address)
if err != nil {
log.Error("Unable to GetListener: %v", err)
return err
}
srv.listener = newWrappedListener(l, srv)
srv.BeforeBegin(srv.network, srv.address)
return srv.Serve(serve)
}
// ListenAndServeTLSConfig listens on the provided network address and then calls
// Serve to handle requests on incoming TLS connections.
func (srv *Server) ListenAndServeTLSConfig(tlsConfig *tls.Config, serve ServeFunction) error {
go srv.awaitShutdown()
if tlsConfig.MinVersion == 0 {
tlsConfig.MinVersion = tls.VersionTLS12
}
l, err := GetListener(srv.network, srv.address)
if err != nil {
log.Error("Unable to get Listener: %v", err)
return err
}
wl := newWrappedListener(l, srv)
srv.listener = tls.NewListener(wl, tlsConfig)
srv.BeforeBegin(srv.network, srv.address)
return srv.Serve(serve)
}
// Serve accepts incoming HTTP connections on the wrapped listener l, creating a new
// service goroutine for each. The service goroutines read requests and then call
// handler to reply to them. Handler is typically nil, in which case the
// DefaultServeMux is used.
//
// In addition to the standard Serve behaviour each connection is added to a
// sync.Waitgroup so that all outstanding connections can be served before shutting
// down the server.
func (srv *Server) Serve(serve ServeFunction) error {
defer log.Debug("Serve() returning... (PID: %d)", syscall.Getpid())
srv.setState(stateRunning)
GetManager().RegisterServer()
err := serve(srv.listener)
log.Debug("Waiting for connections to finish... (PID: %d)", syscall.Getpid())
srv.wg.Wait()
srv.setState(stateTerminate)
GetManager().ServerDone()
// use of closed means that the listeners are closed - i.e. we should be shutting down - return nil
if err == nil || strings.Contains(err.Error(), "use of closed") || strings.Contains(err.Error(), "http: Server closed") {
return nil
}
return err
}
func (srv *Server) getState() state {
srv.lock.RLock()
defer srv.lock.RUnlock()
return srv.state
}
func (srv *Server) setState(st state) {
srv.lock.Lock()
defer srv.lock.Unlock()
srv.state = st
}
type filer interface {
File() (*os.File, error)
}
type wrappedListener struct {
net.Listener
stopped bool
server *Server
}
func newWrappedListener(l net.Listener, srv *Server) *wrappedListener {
return &wrappedListener{
Listener: l,
server: srv,
}
}
func (wl *wrappedListener) Accept() (net.Conn, error) {
var c net.Conn
// Set keepalive on TCPListeners connections.
if tcl, ok := wl.Listener.(*net.TCPListener); ok {
tc, err := tcl.AcceptTCP()
if err != nil {
return nil, err
}
_ = tc.SetKeepAlive(true) // see http.tcpKeepAliveListener
_ = tc.SetKeepAlivePeriod(3 * time.Minute) // see http.tcpKeepAliveListener
c = tc
} else {
var err error
c, err = wl.Listener.Accept()
if err != nil {
return nil, err
}
}
closed := int32(0)
c = &wrappedConn{
Conn: c,
server: wl.server,
closed: &closed,
perWriteTimeout: wl.server.PerWriteTimeout,
perWritePerKbTimeout: wl.server.PerWritePerKbTimeout,
}
wl.server.wg.Add(1)
return c, nil
}
func (wl *wrappedListener) Close() error {
if wl.stopped {
return syscall.EINVAL
}
wl.stopped = true
return wl.Listener.Close()
}
func (wl *wrappedListener) File() (*os.File, error) {
// returns a dup(2) - FD_CLOEXEC flag *not* set so the listening socket can be passed to child processes
return wl.Listener.(filer).File()
}
type wrappedConn struct {
net.Conn
server *Server
closed *int32
deadline time.Time
perWriteTimeout time.Duration
perWritePerKbTimeout time.Duration
}
func (w *wrappedConn) Write(p []byte) (n int, err error) {
if w.perWriteTimeout > 0 {
minTimeout := time.Duration(len(p)/1024) * w.perWritePerKbTimeout
minDeadline := time.Now().Add(minTimeout).Add(w.perWriteTimeout)
w.deadline = w.deadline.Add(minTimeout)
if minDeadline.After(w.deadline) {
w.deadline = minDeadline
}
_ = w.Conn.SetWriteDeadline(w.deadline)
}
return w.Conn.Write(p)
}
func (w *wrappedConn) Close() error {
if atomic.CompareAndSwapInt32(w.closed, 0, 1) {
defer func() {
if err := recover(); err != nil {
select {
case <-GetManager().IsHammer():
// Likely deadlocked request released at hammertime
log.Warn("Panic during connection close! %v. Likely there has been a deadlocked request which has been released by forced shutdown.", err)
default:
log.Error("Panic during connection close! %v", err)
}
}
}()
w.server.wg.Done()
}
return w.Conn.Close()
}