internal/dag: 0s HTTPRoute timeout disables the timeout (#6379)

In Gateway API, a timeout specified as 0s (or any
other explicitly zero-valued duration string) should
disable the timeout rather than use the default
value.

Signed-off-by: Steve Kriss <stephen.kriss@gmail.com>

internal/dag/builder_test.go

@@ -3393,6 +3393,30 @@ func TestDAGInsertGatewayAPI(t *testing.T) {
 				},
 			),
 		},
+		"HTTPRoute rule with 0s (disabled) request timeout": {
+			gatewayclass: validClass,
+			gateway:      gatewayHTTPAllNamespaces,
+			objs: []any{
+				kuardService,
+				makeHTTPRouteWithTimeouts("0s", ""),
+			},
+			want: listeners(
+				&Listener{
+					Name: "http-80",
+					VirtualHosts: virtualhosts(
+						virtualhost("test.projectcontour.io",
+							&Route{
+								PathMatchCondition: prefixString("/"),
+								Clusters:           clustersWeight(service(kuardService)),
+								TimeoutPolicy: RouteTimeoutPolicy{
+									ResponseTimeout: timeout.DisabledSetting(),
+								},
+							},
+						),
+					),
+				},
+			),
+		},
 		"HTTPRoute rule with request and backendRequest timeout": {
 			gatewayclass: validClass,
 			gateway:      gatewayHTTPAllNamespaces,

internal/dag/gatewayapi_processor.go

@@ -1139,6 +1139,11 @@ func parseHTTPRouteTimeouts(httpRouteTimeouts *gatewayapi_v1.HTTPRouteTimeouts)
 		return nil, fmt.Errorf("invalid HTTPRoute.Spec.Rules.Timeouts.Request: %v", err)
 	}
 
+	// For Gateway API a zero-valued timeout means disable the timeout.
+	if requestTimeout.Duration() == 0 {
+		requestTimeout = timeout.DisabledSetting()
+	}
+
 	return &RouteTimeoutPolicy{
 		ResponseTimeout: requestTimeout,
 	}, nil