net/http: update bundled http2, add TestServerKeepAlivesEnabled h1/h2 tests

Updates x/net/http2 to x/net git rev 6dfeb344 for:

   http2: make Server respect http1 Server's SetKeepAlivesEnabled
   https://golang.org/cl/33153

And adds a test in std.

Fixes #17717

Change-Id: I3ba000abb6f3f682261e105d8a4bb93bde6609fe
Reviewed-on: https://go-review.googlesource.com/33231
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tom Bergan <tombergan@google.com>

src/net/http/clientserver_test.go

@@ -44,6 +44,19 @@ func (t *clientServerTest) close() {
 	t.ts.Close()
 }
 
+func (t *clientServerTest) getURL(u string) string {
+	res, err := t.c.Get(u)
+	if err != nil {
+		t.t.Fatal(err)
+	}
+	defer res.Body.Close()
+	slurp, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		t.t.Fatal(err)
+	}
+	return string(slurp)
+}
+
 func (t *clientServerTest) scheme() string {
 	if t.h2 {
 		return "https"

src/net/http/h2_bundle.go

@@ -3549,7 +3549,7 @@ func (sc *http2serverConn) serve() {
 			return
 		case <-gracefulShutdownCh:
 			gracefulShutdownCh = nil
-			sc.goAwayIn(http2ErrCodeNo, 0)
+			sc.startGracefulShutdown()
 		case <-sc.shutdownTimerCh:
 			sc.vlogf("GOAWAY close timer fired; closing conn from %v", sc.conn.RemoteAddr())
 			return
@@ -3834,6 +3834,13 @@ func (sc *http2serverConn) scheduleFrameWrite() {
 	sc.inFrameScheduleLoop = false
 }
 
+// startGracefulShutdown sends a GOAWAY with ErrCodeNo to tell the
+// client we're gracefully shutting down. The connection isn't closed
+// until all current streams are done.
+func (sc *http2serverConn) startGracefulShutdown() {
+	sc.goAwayIn(http2ErrCodeNo, 0)
+}
+
 func (sc *http2serverConn) goAway(code http2ErrCode) {
 	sc.serveG.check()
 	var forceCloseIn time.Duration
@@ -4028,12 +4035,15 @@ func (sc *http2serverConn) closeStream(st *http2stream, err error) {
 	} else {
 		sc.curClientStreams--
 	}
-	if sc.curClientStreams+sc.curPushedStreams == 0 {
-		sc.setConnState(StateIdle)
-	}
 	delete(sc.streams, st.id)
-	if len(sc.streams) == 0 && sc.srv.IdleTimeout != 0 {
-		sc.idleTimer.Reset(sc.srv.IdleTimeout)
+	if len(sc.streams) == 0 {
+		sc.setConnState(StateIdle)
+		if sc.srv.IdleTimeout != 0 {
+			sc.idleTimer.Reset(sc.srv.IdleTimeout)
+		}
+		if http2h1ServerKeepAlivesDisabled(sc.hs) {
+			sc.startGracefulShutdown()
+		}
 	}
 	if p := st.body; p != nil {
 
@@ -4177,7 +4187,7 @@ func (sc *http2serverConn) processGoAway(f *http2GoAwayFrame) error {
 	} else {
 		sc.vlogf("http2: received GOAWAY %+v, starting graceful shutdown", f)
 	}
-	sc.goAwayIn(http2ErrCodeNo, 0)
+	sc.startGracefulShutdown()
 
 	sc.pushEnabled = false
 	return nil
@@ -5181,7 +5191,7 @@ func (sc *http2serverConn) startPush(msg http2startPushRequest) {
 		}
 
 		if sc.maxPushPromiseID+2 >= 1<<31 {
-			sc.goAwayIn(http2ErrCodeNo, 0)
+			sc.startGracefulShutdown()
 			return 0, http2ErrPushLimitReached
 		}
 		sc.maxPushPromiseID += 2
@@ -5326,6 +5336,20 @@ func http2h1ServerShutdownChan(hs *Server) <-chan struct{} {
 // optional test hook for h1ServerShutdownChan.
 var http2testh1ServerShutdownChan func(hs *Server) <-chan struct{}
 
+// h1ServerKeepAlivesDisabled reports whether hs has its keep-alives
+// disabled. See comments on h1ServerShutdownChan above for why
+// the code is written this way.
+func http2h1ServerKeepAlivesDisabled(hs *Server) bool {
+	var x interface{} = hs
+	type I interface {
+		doKeepAlives() bool
+	}
+	if hs, ok := x.(I); ok {
+		return !hs.doKeepAlives()
+	}
+	return false
+}
+
 const (
 	// transportDefaultConnFlow is how many connection-level flow control
 	// tokens we give the server at start-up, past the default 64k.

src/net/http/serve_test.go

@@ -4992,3 +4992,29 @@ func TestServerCloseDeadlock(t *testing.T) {
 	s.Close()
 	s.Close()
 }
+
+// Issue 17717: tests that Server.SetKeepAlivesEnabled is respected by
+// both HTTP/1 and HTTP/2.
+func TestServerKeepAlivesEnabled_h1(t *testing.T) { testServerKeepAlivesEnabled(t, h1Mode) }
+func TestServerKeepAlivesEnabled_h2(t *testing.T) { testServerKeepAlivesEnabled(t, h2Mode) }
+func testServerKeepAlivesEnabled(t *testing.T, h2 bool) {
+	setParallel(t)
+	defer afterTest(t)
+	cst := newClientServerTest(t, h2, HandlerFunc(func(w ResponseWriter, r *Request) {
+		fmt.Fprintf(w, "%v", r.RemoteAddr)
+	}))
+	defer cst.close()
+	srv := cst.ts.Config
+	srv.SetKeepAlivesEnabled(false)
+	a := cst.getURL(cst.ts.URL)
+	if !waitCondition(2*time.Second, 10*time.Millisecond, srv.ExportAllConnsIdle) {
+		t.Fatalf("test server has active conns")
+	}
+	b := cst.getURL(cst.ts.URL)
+	if a == b {
+		t.Errorf("got same connection between first and second requests")
+	}
+	if !waitCondition(2*time.Second, 10*time.Millisecond, srv.ExportAllConnsIdle) {
+		t.Fatalf("test server has active conns")
+	}
+}