Extract rate limiter configuration properties into separate classes

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

@@ -105,6 +105,7 @@
 import org.springframework.cloud.gateway.filter.factory.RequestHeaderSizeGatewayFilterFactory;
 import org.springframework.cloud.gateway.filter.factory.RequestHeaderToRequestUriGatewayFilterFactory;
 import org.springframework.cloud.gateway.filter.factory.RequestRateLimiterGatewayFilterFactory;
+import org.springframework.cloud.gateway.filter.factory.RequestRateLimiterProperties;
 import org.springframework.cloud.gateway.filter.factory.RequestSizeGatewayFilterFactory;
 import org.springframework.cloud.gateway.filter.factory.RetryGatewayFilterFactory;
 import org.springframework.cloud.gateway.filter.factory.RewriteLocationResponseHeaderGatewayFilterFactory;
@@ -213,7 +214,7 @@
  */
 @Configuration(proxyBeanMethods = false)
 @ConditionalOnProperty(name = "spring.cloud.gateway.server.webflux.enabled", matchIfMissing = true)
-@EnableConfigurationProperties
+@EnableConfigurationProperties(RequestRateLimiterProperties.class)
 @AutoConfigureBefore({ HttpHandlerAutoConfiguration.class, WebFluxAutoConfiguration.class })
 @AutoConfigureAfter({ GatewayReactiveLoadBalancerClientAutoConfiguration.class,
 		GatewayClassPathWarningAutoConfiguration.class })
@@ -677,8 +678,8 @@ public PrincipalNameKeyResolver principalNameKeyResolver() {
 	@ConditionalOnBean({ RateLimiter.class, KeyResolver.class })
 	@ConditionalOnEnabledFilter
 	public RequestRateLimiterGatewayFilterFactory requestRateLimiterGatewayFilterFactory(RateLimiter rateLimiter,
-			KeyResolver resolver) {
-		return new RequestRateLimiterGatewayFilterFactory(rateLimiter, resolver);
+			KeyResolver resolver, RequestRateLimiterProperties properties) {
+		return new RequestRateLimiterGatewayFilterFactory(rateLimiter, resolver, properties);
 	}
 
 	@Bean

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

@@ -25,8 +25,10 @@
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.data.redis.autoconfigure.DataRedisReactiveAutoConfiguration;
 import org.springframework.cloud.gateway.filter.ratelimit.RedisRateLimiter;
+import org.springframework.cloud.gateway.filter.ratelimit.RedisRateLimiterProperties;
 import org.springframework.cloud.gateway.route.RedisRouteDefinitionRepository;
 import org.springframework.cloud.gateway.route.RouteDefinition;
 import org.springframework.cloud.gateway.support.ConfigurationService;
@@ -51,6 +53,7 @@
 @ConditionalOnBean(ReactiveRedisTemplate.class)
 @ConditionalOnClass({ RedisTemplate.class, DispatcherHandler.class })
 @ConditionalOnProperty(name = GatewayProperties.PREFIX + ".redis.enabled", matchIfMissing = true)
+@EnableConfigurationProperties(RedisRateLimiterProperties.class)
 class GatewayRedisAutoConfiguration {
 
 	@Bean
@@ -67,8 +70,8 @@ public RedisScript redisRequestRateLimiterScript() {
 	@ConditionalOnMissingBean
 	public RedisRateLimiter redisRateLimiter(ReactiveStringRedisTemplate redisTemplate,
 			@Qualifier(RedisRateLimiter.REDIS_SCRIPT_NAME) RedisScript<List<Long>> redisScript,
-			ConfigurationService configurationService) {
-		return new RedisRateLimiter(redisTemplate, redisScript, configurationService);
+			ConfigurationService configurationService, RedisRateLimiterProperties redisRateLimiterProperties) {
+		return new RedisRateLimiter(redisTemplate, redisScript, configurationService, redisRateLimiterProperties);
 	}
 
 	@Bean

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

@@ -22,7 +22,6 @@
 import org.jspecify.annotations.Nullable;
 import reactor.core.publisher.Mono;
 
-import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.cloud.gateway.filter.GatewayFilter;
 import org.springframework.cloud.gateway.filter.ratelimit.KeyResolver;
 import org.springframework.cloud.gateway.filter.ratelimit.RateLimiter;
@@ -39,7 +38,6 @@
  * User Request Rate Limiter filter. See https://stripe.com/blog/rate-limiters and
  * https://gist.github.com/ptarjan/e38f45f2dfe601419ca3af937fff574d#file-1-check_request_rate_limiter-rb-L11-L34.
  */
-@ConfigurationProperties("spring.cloud.gateway.server.webflux.filter.request-rate-limiter")
 public class RequestRateLimiterGatewayFilterFactory
 		extends AbstractGatewayFilterFactory<RequestRateLimiterGatewayFilterFactory.Config> {
 
@@ -54,24 +52,18 @@ public class RequestRateLimiterGatewayFilterFactory
 
 	private final KeyResolver defaultKeyResolver;
 
-	/**
-	 * Switch to deny requests if the Key Resolver returns an empty key, defaults to true.
-	 */
-	private boolean denyEmptyKey = true;
-
-	/** HttpStatus to return when denyEmptyKey is true, defaults to FORBIDDEN. */
-	private String emptyKeyStatusCode = HttpStatus.FORBIDDEN.name();
-
-	/**
-	 * Switch to throw a {@link HttpClientErrorException} when the request is denied by
-	 * the RateLimiter, defaults to false.
-	 */
-	private boolean throwOnLimit = false;
+	private final RequestRateLimiterProperties properties;
 
 	public RequestRateLimiterGatewayFilterFactory(RateLimiter defaultRateLimiter, KeyResolver defaultKeyResolver) {
+		this(defaultRateLimiter, defaultKeyResolver, new RequestRateLimiterProperties());
+	}
+
+	public RequestRateLimiterGatewayFilterFactory(RateLimiter defaultRateLimiter, KeyResolver defaultKeyResolver,
+			RequestRateLimiterProperties properties) {
 		super(Config.class);
 		this.defaultRateLimiter = defaultRateLimiter;
 		this.defaultKeyResolver = defaultKeyResolver;
+		this.properties = properties;
 	}
 
 	public KeyResolver getDefaultKeyResolver() {
@@ -82,39 +74,87 @@ public RateLimiter getDefaultRateLimiter() {
 		return defaultRateLimiter;
 	}
 
+	/**
+	 * The externalized filter properties bound from configuration.
+	 * @return the properties backing this filter factory
+	 */
+	public RequestRateLimiterProperties getProperties() {
+		return properties;
+	}
+
+	/**
+	 * @return whether requests with an empty key are denied
+	 * @deprecated in favor of {@link RequestRateLimiterProperties#isDenyEmptyKey()} via
+	 * {@link #getProperties()}
+	 */
+	@Deprecated(since = "5.0.3")
 	public boolean isDenyEmptyKey() {
-		return denyEmptyKey;
+		return properties.isDenyEmptyKey();
 	}
 
+	/**
+	 * @param denyEmptyKey whether requests with an empty key are denied
+	 * @deprecated in favor of
+	 * {@link RequestRateLimiterProperties#setDenyEmptyKey(boolean)} via
+	 * {@link #getProperties()}
+	 */
+	@Deprecated(since = "5.0.3")
 	public void setDenyEmptyKey(boolean denyEmptyKey) {
-		this.denyEmptyKey = denyEmptyKey;
+		properties.setDenyEmptyKey(denyEmptyKey);
 	}
 
+	/**
+	 * @return the status code returned when an empty key is denied
+	 * @deprecated in favor of
+	 * {@link RequestRateLimiterProperties#getEmptyKeyStatusCode()} via
+	 * {@link #getProperties()}
+	 */
+	@Deprecated(since = "5.0.3")
 	public String getEmptyKeyStatusCode() {
-		return emptyKeyStatusCode;
+		return properties.getEmptyKeyStatusCode();
 	}
 
+	/**
+	 * @param emptyKeyStatusCode the status code returned when an empty key is denied
+	 * @deprecated in favor of
+	 * {@link RequestRateLimiterProperties#setEmptyKeyStatusCode(String)} via
+	 * {@link #getProperties()}
+	 */
+	@Deprecated(since = "5.0.3")
 	public void setEmptyKeyStatusCode(String emptyKeyStatusCode) {
-		this.emptyKeyStatusCode = emptyKeyStatusCode;
+		properties.setEmptyKeyStatusCode(emptyKeyStatusCode);
 	}
 
+	/**
+	 * @return whether an exception is thrown when the request is rate limited
+	 * @deprecated in favor of {@link RequestRateLimiterProperties#isThrowOnLimit()} via
+	 * {@link #getProperties()}
+	 */
+	@Deprecated(since = "5.0.3")
 	public boolean isThrowOnLimit() {
-		return throwOnLimit;
+		return properties.isThrowOnLimit();
 	}
 
+	/**
+	 * @param throwOnLimit whether an exception is thrown when the request is rate limited
+	 * @deprecated in favor of
+	 * {@link RequestRateLimiterProperties#setThrowOnLimit(boolean)} via
+	 * {@link #getProperties()}
+	 */
+	@Deprecated(since = "5.0.3")
 	public void setThrowOnLimit(boolean throwOnLimit) {
-		this.throwOnLimit = throwOnLimit;
+		properties.setThrowOnLimit(throwOnLimit);
 	}
 
 	@SuppressWarnings("unchecked")
 	@Override
 	public GatewayFilter apply(Config config) {
 		KeyResolver resolver = getOrDefault(config.keyResolver, defaultKeyResolver);
 		RateLimiter<Object> limiter = getOrDefault(config.rateLimiter, defaultRateLimiter);
-		boolean denyEmpty = getOrDefault(config.denyEmptyKey, this.denyEmptyKey);
+		boolean denyEmpty = getOrDefault(config.denyEmptyKey, properties.isDenyEmptyKey());
 		HttpStatusHolder emptyKeyStatus = HttpStatusHolder
-			.parse(getOrDefault(config.emptyKeyStatus, this.emptyKeyStatusCode));
-		boolean throwLimit = getOrDefault(config.throwOnLimit, this.throwOnLimit);
+			.parse(getOrDefault(config.emptyKeyStatus, properties.getEmptyKeyStatusCode()));
+		boolean throwLimit = getOrDefault(config.throwOnLimit, properties.isThrowOnLimit());
 
 		return (exchange, chain) -> resolver.resolve(exchange).defaultIfEmpty(EMPTY_KEY).flatMap(key -> {
 			if (EMPTY_KEY.equals(key)) {

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

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2013-present 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.filter.factory;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.core.style.ToStringCreator;
+import org.springframework.http.HttpStatus;
+import org.springframework.web.client.HttpClientErrorException;
+
+/**
+ * Externalized configuration for {@link RequestRateLimiterGatewayFilterFactory}.
+ * Extracting the bound properties into a dedicated class with a default constructor lets
+ * Spring Cloud's {@code ConfigurationPropertiesRebinder} rebind them on a refresh
+ * (including resetting removed properties to their defaults), which is not possible while
+ * the properties live on the {@link RequestRateLimiterGatewayFilterFactory} bean whose
+ * {@code RateLimiter}/{@code KeyResolver} dependencies are constructor injected.
+ *
+ * @author Aryamann Singh
+ */
+@ConfigurationProperties("spring.cloud.gateway.server.webflux.filter.request-rate-limiter")
+public class RequestRateLimiterProperties {
+
+	/**
+	 * Switch to deny requests if the Key Resolver returns an empty key, defaults to true.
+	 */
+	private boolean denyEmptyKey = true;
+
+	/** HttpStatus to return when denyEmptyKey is true, defaults to FORBIDDEN. */
+	private String emptyKeyStatusCode = HttpStatus.FORBIDDEN.name();
+
+	/**
+	 * Switch to throw a {@link HttpClientErrorException} when the request is denied by
+	 * the RateLimiter, defaults to false.
+	 */
+	private boolean throwOnLimit = false;
+
+	public boolean isDenyEmptyKey() {
+		return denyEmptyKey;
+	}
+
+	public void setDenyEmptyKey(boolean denyEmptyKey) {
+		this.denyEmptyKey = denyEmptyKey;
+	}
+
+	public String getEmptyKeyStatusCode() {
+		return emptyKeyStatusCode;
+	}
+
+	public void setEmptyKeyStatusCode(String emptyKeyStatusCode) {
+		this.emptyKeyStatusCode = emptyKeyStatusCode;
+	}
+
+	public boolean isThrowOnLimit() {
+		return throwOnLimit;
+	}
+
+	public void setThrowOnLimit(boolean throwOnLimit) {
+		this.throwOnLimit = throwOnLimit;
+	}
+
+	@Override
+	public String toString() {
+		return new ToStringCreator(this).append("denyEmptyKey", denyEmptyKey)
+			.append("emptyKeyStatusCode", emptyKeyStatusCode)
+			.append("throwOnLimit", throwOnLimit)
+			.toString();
+	}
+
+}