Injects CacheManager using @Qualifier.

If the user has a custom CacheManager for other uses, this avoids an injection error due to multiple CacheManager beans defined.

Fixes gh-2841

docs/src/main/asciidoc/spring-cloud-gateway.adoc

@@ -2182,6 +2182,8 @@ This filter also implements the automatic calculation of the `max-age value in t
 If `max-age` is present on the original response, the value is rewritten with the number of seconds set in the `timeToLive` configuration parameter.
 In subsequent calls, this value is recalculated with the number of seconds left until the response expires.
 
+WARNING: If your project creates custom `CacheManager` beans, it will either need to be marked with `@Primary` or injected using `@Qualifier`.
+
 === Forward Routing Filter
 
 The `ForwardRoutingFilter` looks for a URI in the exchange attribute `ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR`.

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/config/LocalResponseCacheAutoConfiguration.java

@@ -23,6 +23,7 @@ import com.github.benmanes.caffeine.cache.Weigher;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -52,9 +53,12 @@ public class LocalResponseCacheAutoConfiguration {
 
 	private static final String RESPONSE_CACHE_NAME = "response-cache";
 
+	/* for testing */ static final String RESPONSE_CACHE_MANAGER_NAME = "gatewayCacheManager";
+
 	@Bean
 	public LocalResponseCacheGatewayFilterFactory localResponseCacheGatewayFilterFactory(
-			ResponseCacheManagerFactory responseCacheManagerFactory, CacheManager cacheManager,
+			ResponseCacheManagerFactory responseCacheManagerFactory,
+			@Qualifier(RESPONSE_CACHE_MANAGER_NAME) CacheManager cacheManager,
 			LocalResponseCacheProperties properties) {
 		return new LocalResponseCacheGatewayFilterFactory(responseCacheManagerFactory, responseCache(cacheManager),
 				properties.getTimeToLive());
@@ -70,8 +74,8 @@ public class LocalResponseCacheAutoConfiguration {
 		return new CacheKeyGenerator();
 	}
 
-	@Bean
-	public static CacheManager concurrentMapCacheManager(LocalResponseCacheProperties cacheProperties) {
+	@Bean(name = RESPONSE_CACHE_MANAGER_NAME)
+	public static CacheManager gatewayCacheManager(LocalResponseCacheProperties cacheProperties) {
 		CaffeineCacheManager caffeineCacheManager = new CaffeineCacheManager();
 		caffeineCacheManager.setCaffeine(caffeine(cacheProperties));
 		return caffeineCacheManager;

spring-cloud-gateway-server/src/main/java/org/springframework/cloud/gateway/filter/factory/cache/LocalResponseCacheGatewayFilterFactory.java

@@ -64,7 +64,7 @@ public class LocalResponseCacheGatewayFilterFactory
 			return new ResponseCacheGatewayFilter(cacheManagerFactory.create(globalCache, configuredTimeToLive));
 		}
 		else {
-			Cache routeCache = LocalResponseCacheAutoConfiguration.concurrentMapCacheManager(cacheProperties)
+			Cache routeCache = LocalResponseCacheAutoConfiguration.gatewayCacheManager(cacheProperties)
 					.getCache(config.getRouteId() + "-cache");
 			return new ResponseCacheGatewayFilter(
 					cacheManagerFactory.create(routeCache, cacheProperties.getTimeToLive()));

spring-cloud-gateway-server/src/test/java/org/springframework/cloud/gateway/config/LocalResponseCacheAutoConfigurationTests.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2013-2020 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.config;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.cache.CacheManager;
+import org.springframework.cache.caffeine.CaffeineCacheManager;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Primary;
+
+public class LocalResponseCacheAutoConfigurationTests {
+
+	@Test
+	void onlyOneCacheManagerBeanCreated() {
+		new ApplicationContextRunner()
+				.withConfiguration(AutoConfigurations.of(LocalResponseCacheAutoConfiguration.class))
+				.run(context -> context.containsBean(LocalResponseCacheAutoConfiguration.RESPONSE_CACHE_MANAGER_NAME));
+	}
+
+	@Test
+	void twoCacheManagerBeans() {
+		new ApplicationContextRunner().withConfiguration(
+				AutoConfigurations.of(CustomCacheManagerConfig.class, LocalResponseCacheAutoConfiguration.class))
+				.run(context -> {
+					context.containsBean(LocalResponseCacheAutoConfiguration.RESPONSE_CACHE_MANAGER_NAME);
+					context.containsBean("myCacheManager");
+				});
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	static class CustomCacheManagerConfig {
+
+		@Bean
+		@Primary
+		CacheManager myCacheManager() {
+			return new CaffeineCacheManager();
+		}
+
+		@Bean
+		Object myCacheConsumer(CacheManager cacheManager) {
+			return "";
+		}
+
+	}
+
+}