Merge pull request #4067 from NeatGuyCoding/fix-cookies-null

Add null check for sticky session in LoadBalancerServiceInstanceCookieFilter

Author: ryanjbaxter

spring-cloud-gateway-server-webflux/src/main/java/org/springframework/cloud/gateway/filter/LoadBalancerServiceInstanceCookieFilter.java

@@ -70,7 +70,7 @@ public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
 				? loadBalancerClientFactory.getProperties(serviceInstanceResponse.getServer().getServiceId())
 				: loadBalancerProperties;
 		Objects.requireNonNull(properties, "LoadBalancerProperties must not be null");
-		if (properties.getStickySession() != null && !properties.getStickySession().isAddServiceInstanceCookie()) {
+		if (properties.getStickySession() == null || !properties.getStickySession().isAddServiceInstanceCookie()) {
 			return chain.filter(exchange);
 		}
 		String instanceIdCookieName = properties.getStickySession().getInstanceIdCookieName();

spring-cloud-gateway-server-webflux/src/test/java/org/springframework/cloud/gateway/filter/LoadBalancerServiceInstanceCookieFilterTests.java

@@ -119,6 +119,18 @@ void shouldContinueChainWhenEmptyServiceInstanceCookieName() {
 		assertThat(filteredExchange.getRequest().getHeaders().isEmpty()).isTrue();
 	}
 
+	@Test
+	void shouldContinueChainWhenStickySessionIsNull() {
+		exchange.getAttributes()
+			.put(GATEWAY_LOADBALANCER_RESPONSE_ATTR,
+					new DefaultResponse(new DefaultServiceInstance("test-01", "test", "host", 8080, false)));
+		properties.setStickySession(null);
+
+		ServerWebExchange filteredExchange = testFilter(exchange);
+
+		assertThat(filteredExchange.getRequest().getHeaders().isEmpty()).isTrue();
+	}
+
 	private ServerWebExchange testFilter(ServerWebExchange exchange) {
 		ArgumentCaptor<ServerWebExchange> captor = ArgumentCaptor.forClass(ServerWebExchange.class);
 		when(chain.filter(captor.capture())).thenReturn(Mono.empty());