3 files changed, 449 insertions, 0 deletions
diff --git a/vendor/github.com/facebookgo/httpdown/httpdown.go b/vendor/github.com/facebookgo/httpdown/httpdown.go
new file mode 100644
index 00000000..34c5dea9
--- /dev/null
+++ b/vendor/github.com/facebookgo/httpdown/httpdown.go
@@ -0,0 +1,376 @@
+// 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
+}
diff --git a/vendor/github.com/facebookgo/httpdown/httpdown_example/main.go b/vendor/github.com/facebookgo/httpdown/httpdown_example/main.go
new file mode 100644
index 00000000..9e3c0bff
--- /dev/null
+++ b/vendor/github.com/facebookgo/httpdown/httpdown_example/main.go
@@ -0,0 +1,43 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/facebookgo/httpdown"
+)
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	duration, err := time.ParseDuration(r.FormValue("duration"))
+	if err != nil {
+		http.Error(w, err.Error(), 400)
+		return
+	}
+	fmt.Fprintf(w, "going to sleep %s with pid %d\n", duration, os.Getpid())
+	w.(http.Flusher).Flush()
+	time.Sleep(duration)
+	fmt.Fprintf(w, "slept %s with pid %d\n", duration, os.Getpid())
+}
+
+func main() {
+	server := &http.Server{
+		Addr:    "127.0.0.1:8080",
+		Handler: http.HandlerFunc(handler),
+	}
+	hd := &httpdown.HTTP{
+		StopTimeout: 10 * time.Second,
+		KillTimeout: 1 * time.Second,
+	}
+
+	flag.StringVar(&server.Addr, "addr", server.Addr, "http address")
+	flag.DurationVar(&hd.StopTimeout, "stop-timeout", hd.StopTimeout, "stop timeout")
+	flag.DurationVar(&hd.KillTimeout, "kill-timeout", hd.KillTimeout, "kill timeout")
+	flag.Parse()
+
+	if err := httpdown.ListenAndServe(server, hd); err != nil {
+		panic(err)
+	}
+}
diff --git a/vendor/github.com/facebookgo/httpdown/license b/vendor/github.com/facebookgo/httpdown/license
new file mode 100644
index 00000000..d849082f
--- /dev/null
+++ b/vendor/github.com/facebookgo/httpdown/license
@@ -0,0 +1,30 @@
+BSD License
+
+For httpdown software
+
+Copyright (c) 2015, Facebook, Inc. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+ * Neither the name Facebook nor the names of its contributors may be used to
+   endorse or promote products derived from this software without specific
+   prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.