Enhance AOT-Support (Issue#3171)

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/GatewayServerMvcAutoConfiguration.java

@@ -28,8 +28,10 @@
 import org.springframework.boot.web.client.ClientHttpRequestFactorySettings;
 import org.springframework.boot.web.client.RestClientCustomizer;
 import org.springframework.cloud.gateway.server.mvc.common.ArgumentSupplierBeanPostProcessor;
+import org.springframework.cloud.gateway.server.mvc.config.GatewayMvcAotRuntimeHintsRegistrar;
 import org.springframework.cloud.gateway.server.mvc.config.GatewayMvcProperties;
 import org.springframework.cloud.gateway.server.mvc.config.GatewayMvcPropertiesBeanDefinitionRegistrar;
+import org.springframework.cloud.gateway.server.mvc.config.RouterFunctionHolderFactory;
 import org.springframework.cloud.gateway.server.mvc.filter.FormFilter;
 import org.springframework.cloud.gateway.server.mvc.filter.ForwardedRequestHeadersFilter;
 import org.springframework.cloud.gateway.server.mvc.filter.HttpHeadersFilter.RequestHttpHeadersFilter;
@@ -47,6 +49,8 @@
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Import;
+import org.springframework.context.annotation.ImportRuntimeHints;
+import org.springframework.core.env.Environment;
 import org.springframework.http.client.ClientHttpRequestFactory;
 import org.springframework.http.client.JdkClientHttpRequestFactory;
 import org.springframework.util.StringUtils;
@@ -55,6 +59,7 @@
 @AutoConfiguration(after = { RestTemplateAutoConfiguration.class, RestClientAutoConfiguration.class })
 @ConditionalOnProperty(name = "spring.cloud.gateway.mvc.enabled", matchIfMissing = true)
 @Import(GatewayMvcPropertiesBeanDefinitionRegistrar.class)
+@ImportRuntimeHints(GatewayMvcAotRuntimeHintsRegistrar.class)
 public class GatewayServerMvcAutoConfiguration {
 
 	@Bean
@@ -63,6 +68,11 @@ public static ArgumentSupplierBeanPostProcessor argumentSupplierBeanPostProcesso
 		return new ArgumentSupplierBeanPostProcessor(publisher);
 	}
 
+	@Bean
+	public RouterFunctionHolderFactory routerFunctionHolderFactory(Environment env) {
+		return new RouterFunctionHolderFactory(env);
+	}
+
 	@Bean
 	public RestClientCustomizer gatewayRestClientCustomizer(ClientHttpRequestFactory requestFactory) {
 		return restClientBuilder -> restClientBuilder.requestFactory(requestFactory);

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

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2013-2023 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.server.mvc.config;
+
+import java.util.Arrays;
+import java.util.Set;
+
+import org.springframework.aot.hint.ExecutableMode;
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.ReflectionHints;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.RuntimeHintsRegistrar;
+import org.springframework.cloud.gateway.server.mvc.filter.AfterFilterFunctions;
+import org.springframework.cloud.gateway.server.mvc.filter.BeforeFilterFunctions;
+import org.springframework.cloud.gateway.server.mvc.filter.BodyFilterFunctions;
+import org.springframework.cloud.gateway.server.mvc.filter.Bucket4jFilterFunctions;
+import org.springframework.cloud.gateway.server.mvc.filter.CircuitBreakerFilterFunctions;
+import org.springframework.cloud.gateway.server.mvc.filter.FilterFunctions;
+import org.springframework.cloud.gateway.server.mvc.filter.LoadBalancerFilterFunctions;
+import org.springframework.cloud.gateway.server.mvc.filter.LoadBalancerHandlerSupplier;
+import org.springframework.cloud.gateway.server.mvc.filter.TokenRelayFilterFunctions;
+import org.springframework.cloud.gateway.server.mvc.handler.GatewayRouterFunctions;
+import org.springframework.cloud.gateway.server.mvc.handler.HandlerFunctions;
+import org.springframework.cloud.gateway.server.mvc.predicate.GatewayRequestPredicates;
+import org.springframework.lang.NonNull;
+import org.springframework.util.ClassUtils;
+
+/**
+ * AOT runtime hints registrar on the gateway server mvc.
+ */
+public class GatewayMvcAotRuntimeHintsRegistrar implements RuntimeHintsRegistrar {
+
+	private static final Set<Class<?>> FUNCTION_PROVIDERS = Set.of(HandlerFunctions.class,
+			LoadBalancerHandlerSupplier.class, FilterFunctions.class, BeforeFilterFunctions.class,
+			AfterFilterFunctions.class, TokenRelayFilterFunctions.class, BodyFilterFunctions.class,
+			CircuitBreakerFilterFunctions.class, GatewayRouterFunctions.class, LoadBalancerFilterFunctions.class,
+			GatewayRequestPredicates.class, Bucket4jFilterFunctions.class);
+
+	private static final Set<Class<?>> PROPERTIES = Set.of(FilterProperties.class, PredicateProperties.class,
+			RouteProperties.class);
+
+	@Override
+	public void registerHints(@NonNull RuntimeHints hints, ClassLoader classLoader) {
+		final var reflectionHints = hints.reflection();
+		FUNCTION_PROVIDERS.forEach(c -> addHintsForClass(reflectionHints, c));
+
+		PROPERTIES.forEach(c -> reflectionHints.registerType(c, MemberCategory.PUBLIC_FIELDS,
+				MemberCategory.INVOKE_PUBLIC_METHODS, MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS));
+	}
+
+	/**
+	 * Add hints for the given class. Since we need to register mostly static methods, the
+	 * annotation way with @Reflective does not work here.
+	 * @param reflectionHints the reflection hints
+	 * @param clazz the class to add hints for
+	 */
+	private static void addHintsForClass(ReflectionHints reflectionHints, Class<?> clazz) {
+		if (!ClassUtils.isPresent(clazz.getName(), ClassUtils.getDefaultClassLoader())) {
+			return; // safety net
+		}
+		Arrays.stream(clazz.getMethods()).forEach(m -> reflectionHints.registerMethod(m, ExecutableMode.INVOKE));
+	}
+
+}