Remove rpc error when shut down daemon

RPC connection closing error will be reported every time we shutdown
daemon, this error is expected, so we should remove this error to avoid
confusion to user.

Signed-off-by: Zhang Wei <zhangwei555@huawei.com>

libcontainerd/remote_linux.go

@@ -23,6 +23,7 @@ import (
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/transport"
 )
 
 const (
@@ -42,6 +43,7 @@ type remote struct {
 	stateDir      string
 	rpcAddr       string
 	startDaemon   bool
+	closeManually bool
 	debugLog      bool
 	rpcConn       *grpc.ClientConn
 	clients       []*client
@@ -147,6 +149,7 @@ func (r *remote) Cleanup() {
 	if r.daemonPid == -1 {
 		return
 	}
+	r.closeManually = true
 	r.rpcConn.Close()
 	// Ask the daemon to quit
 	syscall.Kill(r.daemonPid, syscall.SIGTERM)
@@ -254,6 +257,11 @@ func (r *remote) handleEventStream(events containerd.API_EventsClient) {
 	for {
 		e, err := events.Recv()
 		if err != nil {
+			if grpc.ErrorDesc(err) == transport.ErrConnClosing.Desc &&
+				r.closeManually {
+				// ignore error if grpc remote connection is closed manually
+				return
+			}
 			logrus.Errorf("failed to receive event from containerd: %v", err)
 			go r.startEventsMonitor()
 			return