http2/h2demo: update bug link, add idle conn timeouts

Updates golang/go#14204

Change-Id: Id2598c77e2677a50988c00adc8751a9b87751202
Reviewed-on: https://go-review.googlesource.com/19159
Reviewed-by: Andrew Gerrand <adg@golang.org>

http2/h2demo/h2demo.go

@@ -28,7 +28,7 @@ import (
 	"time"
 
 	"camlistore.org/pkg/googlestorage"
-	"camlistore.org/pkg/singleflight"
+	"go4.org/syncutil/singleflight"
 	"golang.org/x/net/http2"
 )
 
@@ -79,7 +79,7 @@ is used transparently by the Go standard library from Go 1.6 and later.
 </p>
 
 <p>Contact info: <i>bradfitz@golang.org</i>, or <a
-href="https://golang.org/issues">file a bug</a>.</p>
+href="https://golang.org/s/http2bug">file a bug</a>.</p>
 
 <h2>Handlers for testing</h2>
 <ul>
@@ -440,11 +440,43 @@ func serveProd() error {
 	return <-errc
 }
 
+const idleTimeout = 5 * time.Minute
+const activeTimeout = 10 * time.Minute
+
+// TODO: put this into the standard library and actually send
+// PING frames and GOAWAY, etc: golang.org/issue/14204
+func idleTimeoutHook() func(net.Conn, http.ConnState) {
+	var mu sync.Mutex
+	m := map[net.Conn]*time.Timer{}
+	return func(c net.Conn, cs http.ConnState) {
+		mu.Lock()
+		defer mu.Unlock()
+		if t, ok := m[c]; ok {
+			delete(m, c)
+			t.Stop()
+		}
+		var d time.Duration
+		switch cs {
+		case http.StateNew, http.StateIdle:
+			d = idleTimeout
+		case http.StateActive:
+			d = activeTimeout
+		default:
+			return
+		}
+		m[c] = time.AfterFunc(d, func() {
+			log.Printf("closing idle conn %v after %v", c.RemoteAddr(), d)
+			go c.Close()
+		})
+	}
+}
+
 func main() {
 	var srv http.Server
 	flag.BoolVar(&http2.VerboseLogs, "verbose", false, "Verbose HTTP/2 debugging.")
 	flag.Parse()
 	srv.Addr = *httpsAddr
+	srv.ConnState = idleTimeoutHook()
 
 	registerHandlers()