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forgejo/vendor/github.com/facebookgo/httpdown/httpdown.go
Lunny Xiao 527c2dd665 Support http service graceful restart (#416)
* support http service graceful restart

* fix dependencies
2016-12-31 09:00:33 +08:00

376 lines
9 KiB
Go

// Package httpdown provides http.ConnState enabled graceful termination of
// http.Server.
package httpdown
import (
"crypto/tls"
"fmt"
"net"
"net/http"
"os"
"os/signal"
"sync"
"syscall"
"time"
"github.com/facebookgo/clock"
"github.com/facebookgo/stats"
)
const (
defaultStopTimeout = time.Minute
defaultKillTimeout = time.Minute
)
// A Server allows encapsulates the process of accepting new connections and
// serving them, and gracefully shutting down the listener without dropping
// active connections.
type Server interface {
// Wait waits for the serving loop to finish. This will happen when Stop is
// called, at which point it returns no error, or if there is an error in the
// serving loop. You must call Wait after calling Serve or ListenAndServe.
Wait() error
// Stop stops the listener. It will block until all connections have been
// closed.
Stop() error
}
// HTTP defines the configuration for serving a http.Server. Multiple calls to
// Serve or ListenAndServe can be made on the same HTTP instance. The default
// timeouts of 1 minute each result in a maximum of 2 minutes before a Stop()
// returns.
type HTTP struct {
// StopTimeout is the duration before we begin force closing connections.
// Defaults to 1 minute.
StopTimeout time.Duration
// KillTimeout is the duration before which we completely give up and abort
// even though we still have connected clients. This is useful when a large
// number of client connections exist and closing them can take a long time.
// Note, this is in addition to the StopTimeout. Defaults to 1 minute.
KillTimeout time.Duration
// Stats is optional. If provided, it will be used to record various metrics.
Stats stats.Client
// Clock allows for testing timing related functionality. Do not specify this
// in production code.
Clock clock.Clock
}
// Serve provides the low-level API which is useful if you're creating your own
// net.Listener.
func (h HTTP) Serve(s *http.Server, l net.Listener) Server {
stopTimeout := h.StopTimeout
if stopTimeout == 0 {
stopTimeout = defaultStopTimeout
}
killTimeout := h.KillTimeout
if killTimeout == 0 {
killTimeout = defaultKillTimeout
}
klock := h.Clock
if klock == nil {
klock = clock.New()
}
ss := &server{
stopTimeout: stopTimeout,
killTimeout: killTimeout,
stats: h.Stats,
clock: klock,
oldConnState: s.ConnState,
listener: l,
server: s,
serveDone: make(chan struct{}),
serveErr: make(chan error, 1),
new: make(chan net.Conn),
active: make(chan net.Conn),
idle: make(chan net.Conn),
closed: make(chan net.Conn),
stop: make(chan chan struct{}),
kill: make(chan chan struct{}),
}
s.ConnState = ss.connState
go ss.manage()
go ss.serve()
return ss
}
// ListenAndServe returns a Server for the given http.Server. It is equivalent
// to ListenAndServe from the standard library, but returns immediately.
// Requests will be accepted in a background goroutine. If the http.Server has
// a non-nil TLSConfig, a TLS enabled listener will be setup.
func (h HTTP) ListenAndServe(s *http.Server) (Server, error) {
addr := s.Addr
if addr == "" {
if s.TLSConfig == nil {
addr = ":http"
} else {
addr = ":https"
}
}
l, err := net.Listen("tcp", addr)
if err != nil {
stats.BumpSum(h.Stats, "listen.error", 1)
return nil, err
}
if s.TLSConfig != nil {
l = tls.NewListener(l, s.TLSConfig)
}
return h.Serve(s, l), nil
}
// server manages the serving process and allows for gracefully stopping it.
type server struct {
stopTimeout time.Duration
killTimeout time.Duration
stats stats.Client
clock clock.Clock
oldConnState func(net.Conn, http.ConnState)
server *http.Server
serveDone chan struct{}
serveErr chan error
listener net.Listener
new chan net.Conn
active chan net.Conn
idle chan net.Conn
closed chan net.Conn
stop chan chan struct{}
kill chan chan struct{}
stopOnce sync.Once
stopErr error
}
func (s *server) connState(c net.Conn, cs http.ConnState) {
if s.oldConnState != nil {
s.oldConnState(c, cs)
}
switch cs {
case http.StateNew:
s.new <- c
case http.StateActive:
s.active <- c
case http.StateIdle:
s.idle <- c
case http.StateHijacked, http.StateClosed:
s.closed <- c
}
}
func (s *server) manage() {
defer func() {
close(s.new)
close(s.active)
close(s.idle)
close(s.closed)
close(s.stop)
close(s.kill)
}()
var stopDone chan struct{}
conns := map[net.Conn]http.ConnState{}
var countNew, countActive, countIdle float64
// decConn decrements the count associated with the current state of the
// given connection.
decConn := func(c net.Conn) {
switch conns[c] {
default:
panic(fmt.Errorf("unknown existing connection: %s", c))
case http.StateNew:
countNew--
case http.StateActive:
countActive--
case http.StateIdle:
countIdle--
}
}
// setup a ticker to report various values every minute. if we don't have a
// Stats implementation provided, we Stop it so it never ticks.
statsTicker := s.clock.Ticker(time.Minute)
if s.stats == nil {
statsTicker.Stop()
}
for {
select {
case <-statsTicker.C:
// we'll only get here when s.stats is not nil
s.stats.BumpAvg("http-state.new", countNew)
s.stats.BumpAvg("http-state.active", countActive)
s.stats.BumpAvg("http-state.idle", countIdle)
s.stats.BumpAvg("http-state.total", countNew+countActive+countIdle)
case c := <-s.new:
conns[c] = http.StateNew
countNew++
case c := <-s.active:
decConn(c)
countActive++
conns[c] = http.StateActive
case c := <-s.idle:
decConn(c)
countIdle++
conns[c] = http.StateIdle
// if we're already stopping, close it
if stopDone != nil {
c.Close()
}
case c := <-s.closed:
stats.BumpSum(s.stats, "conn.closed", 1)
decConn(c)
delete(conns, c)
// if we're waiting to stop and are all empty, we just closed the last
// connection and we're done.
if stopDone != nil && len(conns) == 0 {
close(stopDone)
return
}
case stopDone = <-s.stop:
// if we're already all empty, we're already done
if len(conns) == 0 {
close(stopDone)
return
}
// close current idle connections right away
for c, cs := range conns {
if cs == http.StateIdle {
c.Close()
}
}
// continue the loop and wait for all the ConnState updates which will
// eventually close(stopDone) and return from this goroutine.
case killDone := <-s.kill:
// force close all connections
stats.BumpSum(s.stats, "kill.conn.count", float64(len(conns)))
for c := range conns {
c.Close()
}
// don't block the kill.
close(killDone)
// continue the loop and we wait for all the ConnState updates and will
// return from this goroutine when we're all done. otherwise we'll try to
// send those ConnState updates on closed channels.
}
}
}
func (s *server) serve() {
stats.BumpSum(s.stats, "serve", 1)
s.serveErr <- s.server.Serve(s.listener)
close(s.serveDone)
close(s.serveErr)
}
func (s *server) Wait() error {
if err := <-s.serveErr; !isUseOfClosedError(err) {
return err
}
return nil
}
func (s *server) Stop() error {
s.stopOnce.Do(func() {
defer stats.BumpTime(s.stats, "stop.time").End()
stats.BumpSum(s.stats, "stop", 1)
// first disable keep-alive for new connections
s.server.SetKeepAlivesEnabled(false)
// then close the listener so new connections can't connect come thru
closeErr := s.listener.Close()
<-s.serveDone
// then trigger the background goroutine to stop and wait for it
stopDone := make(chan struct{})
s.stop <- stopDone
// wait for stop
select {
case <-stopDone:
case <-s.clock.After(s.stopTimeout):
defer stats.BumpTime(s.stats, "kill.time").End()
stats.BumpSum(s.stats, "kill", 1)
// stop timed out, wait for kill
killDone := make(chan struct{})
s.kill <- killDone
select {
case <-killDone:
case <-s.clock.After(s.killTimeout):
// kill timed out, give up
stats.BumpSum(s.stats, "kill.timeout", 1)
}
}
if closeErr != nil && !isUseOfClosedError(closeErr) {
stats.BumpSum(s.stats, "listener.close.error", 1)
s.stopErr = closeErr
}
})
return s.stopErr
}
func isUseOfClosedError(err error) bool {
if err == nil {
return false
}
if opErr, ok := err.(*net.OpError); ok {
err = opErr.Err
}
return err.Error() == "use of closed network connection"
}
// ListenAndServe is a convenience function to serve and wait for a SIGTERM
// or SIGINT before shutting down.
func ListenAndServe(s *http.Server, hd *HTTP) error {
if hd == nil {
hd = &HTTP{}
}
hs, err := hd.ListenAndServe(s)
if err != nil {
return err
}
waiterr := make(chan error, 1)
go func() {
defer close(waiterr)
waiterr <- hs.Wait()
}()
signals := make(chan os.Signal, 10)
signal.Notify(signals, syscall.SIGTERM, syscall.SIGINT)
select {
case err := <-waiterr:
if err != nil {
return err
}
case <-signals:
signal.Stop(signals)
if err := hs.Stop(); err != nil {
return err
}
if err := <-waiterr; err != nil {
return err
}
}
return nil
}