Adds CachingRouteReader

This allows an atomic refresh of routes.

src/main/java/org/springframework/cloud/gateway/actuate/GatewayEndpoint.java

@@ -5,6 +5,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 
+import org.springframework.cloud.gateway.api.CachingRouteReader;
 import org.springframework.cloud.gateway.api.RouteReader;
 import org.springframework.cloud.gateway.config.Route;
 import org.springframework.cloud.gateway.filter.GlobalFilter;
@@ -13,9 +14,11 @@ import org.springframework.cloud.gateway.handler.FilteringWebHandler;
 import org.springframework.core.Ordered;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 /**
@@ -43,9 +46,17 @@ public class GatewayEndpoint {/*extends AbstractEndpoint<Map<String, Object>> {*
 
 	/*@Override
 	public Map<String, Object> invoke() {
-
 	}*/
 
+	//TODO: this should really be a listener that responds to a RefreshEvent
+	@PostMapping("/refresh")
+	public Flux<Route> refresh() {
+		if (this.routeReader instanceof CachingRouteReader) {
+			return ((CachingRouteReader)this.routeReader).refresh();
+		}
+		return Flux.empty();
+	}
+
 	@GetMapping("/globalfilters")
 	public Map<String, Object> globalfilters() {
 		return getNamesToOrders(this.globalFilters);

src/main/java/org/springframework/cloud/gateway/api/CachingRouteReader.java

@@ -0,0 +1,40 @@
+package org.springframework.cloud.gateway.api;
+
+import java.util.List;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.springframework.cloud.gateway.config.Route;
+
+import reactor.core.publisher.Flux;
+
+/**
+ * @author Spencer Gibb
+ */
+public class CachingRouteReader implements RouteReader {
+
+	private final RouteReader delegate;
+	private final AtomicReference<List<Route>> cachedRoutes = new AtomicReference<>();
+
+	public CachingRouteReader(RouteReader delegate) {
+		this.delegate = delegate;
+		this.cachedRoutes.compareAndSet(null, collectRoutes());
+	}
+
+	@Override
+	public Flux<Route> getRoutes() {
+		return Flux.fromIterable(this.cachedRoutes.get());
+	}
+
+	/**
+	 * Sets the new routes
+	 * @return old routes
+	 */
+	public Flux<Route> refresh() {
+		return Flux.fromIterable(this.cachedRoutes.getAndUpdate(
+				routes -> CachingRouteReader.this.collectRoutes()));
+	}
+
+	private List<Route> collectRoutes() {
+		return this.delegate.getRoutes().collectList().block();
+	}
+}

src/main/java/org/springframework/cloud/gateway/config/GatewayAutoConfiguration.java

@@ -10,6 +10,7 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
 import org.springframework.cloud.gateway.actuate.GatewayEndpoint;
+import org.springframework.cloud.gateway.api.CachingRouteReader;
 import org.springframework.cloud.gateway.api.RouteReader;
 import org.springframework.cloud.gateway.filter.GlobalFilter;
 import org.springframework.cloud.gateway.filter.LoadBalancerClientFilter;
@@ -67,8 +68,9 @@ public class GatewayAutoConfiguration {
 
 	@Bean
 	@ConditionalOnMissingBean(RouteReader.class)
-	public PropertiesRouteReader propertiesRouteReader(GatewayProperties properties) {
-		return new PropertiesRouteReader(properties);
+	public RouteReader propertiesRouteReader(GatewayProperties properties) {
+		//TODO: how to automatically apply CachingRouteReader
+		return new CachingRouteReader(new PropertiesRouteReader(properties));
 	}
 
 	@Bean

src/main/java/org/springframework/cloud/gateway/handler/RoutePredicateHandlerMapping.java

@@ -31,8 +31,6 @@ public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
 	private RouteReader routeReader;
 	private WebHandler webHandler;
 
-	private List<Route> routes;
-
 	public RoutePredicateHandlerMapping(WebHandler webHandler, Map<String, RoutePredicate> predicates,
 										RouteReader routeReader) {
 		this.webHandler = webHandler;
@@ -58,24 +56,13 @@ public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
 		return name.replace(RoutePredicate.class.getSimpleName(), "");
 	}
 
-	@Override
-	protected void initApplicationContext() throws BeansException {
-		super.initApplicationContext();
-		Flux<Route> routes = this.routeReader.getRoutes();
-		registerHandlers(routes.collectList().block()); //TODO: convert rest of class to Reactive
-	}
-
-	protected void registerHandlers(List<Route> routes) {
-		this.routes = routes;
-	}
-
 	@Override
 	protected Mono<?> getHandlerInternal(ServerWebExchange exchange) {
 		exchange.getAttributes().put(GATEWAY_HANDLER_MAPPER_ATTR, getClass().getSimpleName());
 
 		Route route;
 		try {
-			route = lookupRoute(this.routes, exchange);
+			route = lookupRoute(exchange);
 		}
 		catch (Exception ex) {
 			return Mono.error(ex);
@@ -107,7 +94,9 @@ public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
 	}
 
 
-	protected Route lookupRoute(List<Route> routes, ServerWebExchange exchange) throws Exception {
+	protected Route lookupRoute(ServerWebExchange exchange) throws Exception {
+		List<Route> routes = this.routeReader.getRoutes().collectList().block(); //TODO: convert rest of class to Reactive
+
 		for (Route route : routes) {
 			if (!route.getPredicates().isEmpty()) {
 				//TODO: cache predicate

src/test/java/org/springframework/cloud/gateway/test/GatewayTestApplication.java

@@ -5,7 +5,9 @@ import org.springframework.boot.SpringBootConfiguration;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.cloud.client.discovery.DiscoveryClient;
 import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
+import org.springframework.cloud.gateway.api.CachingRouteReader;
 import org.springframework.cloud.gateway.api.CompositeRouteReader;
+import org.springframework.cloud.gateway.api.RouteReader;
 import org.springframework.cloud.gateway.config.GatewayProperties;
 import org.springframework.cloud.gateway.config.PropertiesRouteReader;
 import org.springframework.cloud.gateway.discovery.DiscoveryClientRouteReader;
@@ -42,9 +44,11 @@ public class GatewayTestApplication {
 
 		@Bean
 		@Primary
-		public CompositeRouteReader compositeRouteReader(DiscoveryClientRouteReader discoveryClientRouteReader,
-														 PropertiesRouteReader propertiesRouteReader) {
-			return new CompositeRouteReader(Flux.just(discoveryClientRouteReader, propertiesRouteReader));
+		public RouteReader compositeRouteReader(DiscoveryClientRouteReader discoveryClientRouteReader,
+												PropertiesRouteReader propertiesRouteReader) {
+			final Flux<RouteReader> flux = Flux.just(discoveryClientRouteReader, propertiesRouteReader);
+			final CompositeRouteReader composite = new CompositeRouteReader(flux);
+			return new CachingRouteReader(composite);
 		}
 	}