grpc-proxy: add client keepalive

Longhorn-3967

Signed-off-by: Chin-Ya Huang <chin-ya.huang@suse.com>

pkg/client/proxy.go

@@ -9,6 +9,7 @@ import (
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/keepalive"
 
 	rpc "github.com/longhorn/longhorn-instance-manager/pkg/imrpc"
 	"github.com/longhorn/longhorn-instance-manager/pkg/meta"
@@ -60,7 +61,14 @@ type ProxyClient struct {
 
 func NewProxyClient(ctx context.Context, ctxCancel context.CancelFunc, address string, port int) (*ProxyClient, error) {
 	getServiceCtx := func(serviceUrl string) (ServiceContext, error) {
-		connection, err := grpc.Dial(serviceUrl, grpc.WithInsecure())
+		dialOptions := []grpc.DialOption{
+			grpc.WithInsecure(),
+			grpc.WithKeepaliveParams(keepalive.ClientParameters{
+				Time:                time.Second * 10,
+				PermitWithoutStream: true,
+			}),
+		}
+		connection, err := grpc.Dial(serviceUrl, dialOptions...)
 		if err != nil {
 			return ServiceContext{}, errors.Wrapf(err, "cannot connect to ProxyService %v", serviceUrl)
 		}