Adds listener to publish RefreshRoutesEvent when needed.

It will publish on InstanceRegisteredEvent and if a HeartbeatMonitor decides if an update is needed based on a HeartbeatEvent.

fixes gh-236

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/actuate/GatewayControllerEndpoint.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,7 +27,7 @@ import org.apache.commons.logging.LogFactory;
 import org.springframework.boot.actuate.endpoint.web.annotation.RestControllerEndpoint;
 import org.springframework.cloud.gateway.filter.GlobalFilter;
 import org.springframework.cloud.gateway.filter.factory.GatewayFilterFactory;
-import org.springframework.cloud.gateway.route.RefreshRoutesEvent;
+import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
 import org.springframework.cloud.gateway.route.Route;
 import org.springframework.cloud.gateway.route.RouteDefinition;
 import org.springframework.cloud.gateway.route.RouteDefinitionLocator;
@@ -79,7 +79,6 @@ public class GatewayControllerEndpoint implements ApplicationEventPublisherAware
 
 	// TODO: Add uncommited or new but not active routes endpoint
 
-	//TODO: this should really be a listener that responds to a RefreshEvent
 	@PostMapping("/refresh")
 	public Mono<Void> refresh() {
 	    this.publisher.publishEvent(new RefreshRoutesEvent(this));

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/config/GatewayAutoConfiguration.java

@@ -90,7 +90,9 @@ import org.springframework.cloud.gateway.route.RouteDefinitionRepository;
 import org.springframework.cloud.gateway.route.RouteDefinitionRouteLocator;
 import org.springframework.cloud.gateway.route.RouteDefinitionWriter;
 import org.springframework.cloud.gateway.route.RouteLocator;
+import org.springframework.cloud.gateway.route.RouteRefreshListener;
 import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
+import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -244,10 +246,16 @@ public class GatewayAutoConfiguration {
 
 	@Bean
 	@Primary
+	//TODO: property to disable composite?
 	public RouteLocator cachedCompositeRouteLocator(List<RouteLocator> routeLocators) {
 		return new CachingRouteLocator(new CompositeRouteLocator(Flux.fromIterable(routeLocators)));
 	}
 
+	@Bean
+	public RouteRefreshListener routeRefreshListener(ApplicationEventPublisher publisher) {
+		return new RouteRefreshListener(publisher);
+	}
+
 	@Bean
 	public FilteringWebHandler filteringWebHandler(List<GlobalFilter> globalFilters) {
 		return new FilteringWebHandler(globalFilters);

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/event/RefreshRoutesEvent.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,7 +15,7 @@
  *
  */
 
-package org.springframework.cloud.gateway.route;
+package org.springframework.cloud.gateway.event;
 
 import org.springframework.context.ApplicationEvent;
 

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/route/CachingRouteDefinitionLocator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,9 +20,11 @@ package org.springframework.cloud.gateway.route;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
 
-import org.springframework.context.event.EventListener;
 import reactor.core.publisher.Flux;
 
+import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
+import org.springframework.context.event.EventListener;
+
 /**
  * @author Spencer Gibb
  */

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/route/CachingRouteLocator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2017 the original author or authors.
+ * Copyright 2013-2018 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,11 +20,12 @@ package org.springframework.cloud.gateway.route;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicReference;
 
+import reactor.core.publisher.Flux;
+
+import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
 import org.springframework.context.event.EventListener;
 import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 
-import reactor.core.publisher.Flux;
-
 /**
  * @author Spencer Gibb
  */

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/route/RouteRefreshListener.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2013-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.springframework.cloud.gateway.route;
+
+import org.springframework.cloud.client.discovery.event.HeartbeatEvent;
+import org.springframework.cloud.client.discovery.event.HeartbeatMonitor;
+import org.springframework.cloud.client.discovery.event.InstanceRegisteredEvent;
+import org.springframework.cloud.client.discovery.event.ParentHeartbeatEvent;
+import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
+import org.springframework.context.ApplicationEvent;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.context.ApplicationListener;
+import org.springframework.util.Assert;
+
+// see ZuulDiscoveryRefreshListener
+// TODO: make abstract class in commons?
+public class RouteRefreshListener
+		implements ApplicationListener<ApplicationEvent> {
+
+	private HeartbeatMonitor monitor = new HeartbeatMonitor();
+	private final ApplicationEventPublisher publisher;
+
+	public RouteRefreshListener(ApplicationEventPublisher publisher) {
+		Assert.notNull(publisher, "publisher may not be null");
+		this.publisher = publisher;
+	}
+
+	@Override
+	public void onApplicationEvent(ApplicationEvent event) {
+		if (event instanceof InstanceRegisteredEvent) {
+			reset();
+		}
+		else if (event instanceof ParentHeartbeatEvent) {
+			ParentHeartbeatEvent e = (ParentHeartbeatEvent) event;
+			resetIfNeeded(e.getValue());
+		}
+		else if (event instanceof HeartbeatEvent) {
+			HeartbeatEvent e = (HeartbeatEvent) event;
+			resetIfNeeded(e.getValue());
+		}
+	}
+
+	private void resetIfNeeded(Object value) {
+		if (this.monitor.update(value)) {
+			reset();
+		}
+	}
+
+	private void reset() {
+		this.publisher.publishEvent(new RefreshRoutesEvent(this));
+	}
+
+}

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/route/RouteRefreshListenerTests.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2013-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.springframework.cloud.gateway.route;
+
+import org.junit.Test;
+
+import org.springframework.cloud.client.discovery.event.HeartbeatEvent;
+import org.springframework.cloud.client.discovery.event.InstanceRegisteredEvent;
+import org.springframework.cloud.client.discovery.event.ParentHeartbeatEvent;
+import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
+import org.springframework.context.ApplicationEventPublisher;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+public class RouteRefreshListenerTests {
+
+	@Test
+	public void onInstanceRegisteredEvent() {
+		ApplicationEventPublisher publisher = mock(ApplicationEventPublisher.class);
+		RouteRefreshListener listener = new RouteRefreshListener(publisher);
+
+		listener.onApplicationEvent(new InstanceRegisteredEvent<>(this, new Object()));
+
+		verify(publisher).publishEvent(any(RefreshRoutesEvent.class));
+	}
+
+	@Test
+	public void onHeartbeatEvent() {
+		ApplicationEventPublisher publisher = mock(ApplicationEventPublisher.class);
+		RouteRefreshListener listener = new RouteRefreshListener(publisher);
+
+		listener.onApplicationEvent(new HeartbeatEvent(this, 1L));
+		listener.onApplicationEvent(new HeartbeatEvent(this, 1L));
+		listener.onApplicationEvent(new HeartbeatEvent(this, 2L));
+
+		verify(publisher, times(2)).publishEvent(any(RefreshRoutesEvent.class));
+	}
+
+	@Test
+	public void onParentHeartbeatEvent() {
+		ApplicationEventPublisher publisher = mock(ApplicationEventPublisher.class);
+		RouteRefreshListener listener = new RouteRefreshListener(publisher);
+
+		listener.onApplicationEvent(new ParentHeartbeatEvent(this, 1L));
+		listener.onApplicationEvent(new ParentHeartbeatEvent(this, 1L));
+		listener.onApplicationEvent(new ParentHeartbeatEvent(this, 2L));
+
+		verify(publisher, times(2)).publishEvent(any(RefreshRoutesEvent.class));
+	}
+}

spring-cloud-starter-gateway/pom.xml

@@ -20,6 +20,10 @@
 		<main.basedir>${basedir}/../..</main.basedir>
 	</properties>
 	<dependencies>
+		<dependency>
+			<groupId>org.springframework.cloud</groupId>
+			<artifactId>spring-cloud-starter</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.cloud</groupId>
 			<artifactId>spring-cloud-gateway-core</artifactId>