Do not block on stream server close.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/service.go

@@ -262,8 +262,21 @@ func (c *criContainerdService) Run(startGRPC bool) error {
 
 	<-eventMonitorCloseCh
 	logrus.Info("Event monitor stopped")
-	<-streamServerCloseCh
-	logrus.Info("Stream server stopped")
+	// There is a race condition with http.Server.Serve.
+	// When `Close` is called at the same time with `Serve`, `Close`
+	// may finish first, and `Serve` may still block.
+	// See https://github.com/golang/go/issues/20239.
+	// Here we set a 2 second timeout for the stream server wait,
+	// if it timeout, an error log is generated.
+	// TODO(random-liu): Get rid of this after https://github.com/golang/go/issues/20239
+	// is fixed.
+	const streamServerStopTimeout = 2 * time.Second
+	select {
+	case <-streamServerCloseCh:
+		logrus.Info("Stream server stopped")
+	case <-time.After(streamServerStopTimeout):
+		logrus.Errorf("Stream server is not stopped in %q", streamServerStopTimeout)
+	}
 	if startGRPC {
 		// Only wait for grpc server close channel when grpc server is started.
 		<-grpcServerCloseCh