Handle NS and NSE server wait timeouts cleanly

gRPC server-side streaming calls should be closed by returning nil so
we need to figure out what the timeout Error looks like and return nil
when it happens. In this case the Error has an "unknown" code so we
use the error message. When it happens we return nil and the
server-side streaming call is closed cleanly.

Signed-off-by: Toby Cabot <[email protected]>

pkg/registry/etcd/ns_server.go

@@ -162,7 +162,13 @@ func (n *etcdNSRegistryServer) Find(query *registry.NetworkServiceQuery, s regis
 		}
 	}
 	if query.Watch {
-		if err := n.watch(query, s); err != nil && !errors.Is(err, io.EOF) {
+		if err := n.watch(query, s); err != nil {
+			// If we have timed out then return nil to close the stream
+			// cleanly
+			if errors.Is(err, io.EOF) || err.Error() == "context canceled" {
+				logger.Debug("watch timed out, closing stream")
+				return nil
+			}
 			return err
 		}
 	}

pkg/registry/etcd/nse_server.go

@@ -113,7 +113,13 @@ func (n *etcdNSERegistryServer) Find(query *registry.NetworkServiceEndpointQuery
 		}
 	}
 	if query.Watch {
-		if err := n.watch(query, s); err != nil && !errors.Is(err, io.EOF) {
+		if err := n.watch(query, s); err != nil {
+			// If we have timed out then return nil to close the stream
+			// cleanly
+			if errors.Is(err, io.EOF) || err.Error() == "context canceled" {
+				logger.Debug("watch timed out, closing stream")
+				return nil
+			}
 			return err
 		}
 	}