Moves blocking random uuid to route definition locator.

This allows the blocking calls to be put on the elastic scheduler.

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

@@ -16,22 +16,50 @@
 
 package org.springframework.cloud.gateway.route;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.core.scheduler.Schedulers;
+
+import org.springframework.util.AlternativeJdkIdGenerator;
+import org.springframework.util.IdGenerator;
 
 /**
  * @author Spencer Gibb
  */
 public class CompositeRouteDefinitionLocator implements RouteDefinitionLocator {
 
+	private static final Log log = LogFactory
+			.getLog(CompositeRouteDefinitionLocator.class);
+
 	private final Flux<RouteDefinitionLocator> delegates;
 
+	private final IdGenerator idGenerator;
+
 	public CompositeRouteDefinitionLocator(Flux<RouteDefinitionLocator> delegates) {
+		this(delegates, new AlternativeJdkIdGenerator());
+	}
+
+	public CompositeRouteDefinitionLocator(Flux<RouteDefinitionLocator> delegates,
+			IdGenerator idGenerator) {
 		this.delegates = delegates;
+		this.idGenerator = idGenerator;
 	}
 
 	@Override
 	public Flux<RouteDefinition> getRouteDefinitions() {
-		return this.delegates.flatMap(RouteDefinitionLocator::getRouteDefinitions);
+		return this.delegates.flatMap(RouteDefinitionLocator::getRouteDefinitions)
+				.flatMap(routeDefinition -> Mono.justOrEmpty(routeDefinition.getId())
+						.defaultIfEmpty(idGenerator.generateId().toString())
+						.publishOn(Schedulers.elastic()).map(id -> {
+							routeDefinition.setId(id);
+							if (log.isDebugEnabled()) {
+								log.debug(
+										"Id set on route definition: " + routeDefinition);
+							}
+							return routeDefinition;
+						}));
 	}
 
 }

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

@@ -23,6 +23,7 @@ import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
 import org.springframework.cloud.gateway.support.NotFoundException;
+import org.springframework.util.StringUtils;
 
 import static java.util.Collections.synchronizedMap;
 
@@ -37,6 +38,9 @@ public class InMemoryRouteDefinitionRepository implements RouteDefinitionReposit
 	@Override
 	public Mono<Void> save(Mono<RouteDefinition> route) {
 		return route.flatMap(r -> {
+			if (StringUtils.isEmpty(r.getId())) {
+				return Mono.error(new IllegalArgumentException("id may not be empty"));
+			}
 			routes.put(r.getId(), r);
 			return Mono.empty();
 		});

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

@@ -20,7 +20,6 @@ import java.net.URI;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
-import java.util.UUID;
 
 import javax.validation.Valid;
 import javax.validation.ValidationException;
@@ -39,8 +38,7 @@ import static org.springframework.util.StringUtils.tokenizeToStringArray;
 @Validated
 public class RouteDefinition {
 
-	@NotEmpty
-	private String id = UUID.randomUUID().toString();
+	private String id;
 
 	@NotEmpty
 	@Valid

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

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2013-2019 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
+ *
+ *      https://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.junit.runner.RunWith;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.cloud.gateway.config.GatewayProperties;
+import org.springframework.cloud.gateway.test.BaseWebClientTests;
+import org.springframework.context.annotation.Import;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.web.bind.annotation.RestController;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = RANDOM_PORT)
+@DirtiesContext
+@ActiveProfiles("defaultid")
+public class RouteDefinitionDefaultIdTests {
+
+	@Autowired
+	private GatewayProperties properties;
+
+	@Test
+	public void testDefaultIdWorks() {
+		assertThat(properties.getRoutes()).hasSize(1);
+		RouteDefinition routeDefinition = properties.getRoutes().get(0);
+		assertThat(routeDefinition.getId()).isNotNull();
+	}
+
+	@EnableAutoConfiguration
+	@SpringBootConfiguration
+	@Import(BaseWebClientTests.DefaultTestConfig.class)
+	@RestController
+	public static class TestConfig {
+
+	}
+
+}

spring-cloud-gateway-core/src/test/resources/application-defaultid.yml

@@ -0,0 +1,11 @@
+spring:
+  cloud:
+    gateway:
+      default-filters:
+      - PrefixPath=/httpbin
+      routes:
+      - uri: https://defaultrouteid.example.org
+        order: 10000
+        predicates:
+        - Path=/defaultrouteid/**
+