diff --git a/docs/modules/ROOT/pages/spring-cloud-commons/common-abstractions.adoc b/docs/modules/ROOT/pages/spring-cloud-commons/common-abstractions.adoc index c8a0f336b..8ab29949c 100644 --- a/docs/modules/ROOT/pages/spring-cloud-commons/common-abstractions.adoc +++ b/docs/modules/ROOT/pages/spring-cloud-commons/common-abstractions.adoc @@ -218,6 +218,89 @@ IMPORTANT: Notice the use of the `@Primary` annotation on the plain `RestTemplat TIP: If you see errors such as `java.lang.IllegalArgumentException: Can not set org.springframework.web.client.RestTemplate field com.my.app.Foo.restTemplate to com.sun.proxy.$Proxy89`, try injecting `RestOperations` or setting `spring.aop.proxyTargetClass=true`. +[[rest-template-builder-loadbalancer-client]] +== Using `@LoadBalanced RestTemplateBuilder` to create a LoadBalancer Client + +You can also configure a `RestTemplate` to use a Load-Balancer client by annotating a +`RestTemplateBuilder` bean with `@LoadBalanced`: + +[source,java,indent=0] +---- +import org.springframework.boot.web.client.RestTemplateBuilder;@Configuration +public class MyConfiguration { + + @Bean + @LoadBalanced + RestTemplateBuilder loadBalancedRestTemplateBuilder() { + return new RestTemplateBuilder(); + } +} + +public class MyClass { + + private final RestTemplate restTemplate; + + MyClass(@LoadBalanced RestTemplateBuilder restTemplateBuilder) { + this.restTemplate = restTemplateBuilder.build(); + } + + public String getStores() { + return restTemplate.getForObject("http://stores/stores", String.class); + } +} +---- + +The URI needs to use a virtual host name (that is, a service name, not a host name). +The `BlockingLoadBalancerClient` is used to create a full physical address. + +IMPORTANT: To use it, add xref:spring-cloud-commons/loadbalancer.adoc#spring-cloud-loadbalancer-starter[Spring Cloud LoadBalancer starter] to your project. + +[[multiple-resttemplate-builder-beans]] +=== Multiple `RestTemplateBuilder` beans + +If you want a `RestTemplateBuilder` that is not load-balanced, create a `RestTemplateBuilder` bean and inject it. +To access the load-balanced `RestTemplateBuilder`, use the `@LoadBalanced` qualifier when you create your `@Bean`, as the following example shows: + +[source,java,indent=0] +---- +@Configuration +public class MyConfiguration { + + @LoadBalanced + @Bean + RestTemplateBuilder loadBalancedRestTemplateBuilder() { + return new RestTemplateBuilder(); + } + + @Primary + @Bean + RestTemplateBuilder restTemplateBuilder() { + return new RestTemplateBuilder(); + } +} + +public class MyClass { + + @Autowired + private RestTemplateBuilder restTemplateBuilder; + + @Autowired + @LoadBalanced + private RestTemplateBuilder loadBalanced; + + public String doOtherStuff() { + return loadBalanced.getForObject("http://stores/stores", String.class); + } + + public String doStuff() { + return restTemplateBuilder.build().getForObject("http://example.com", String.class); + } +} +---- + +IMPORTANT: Notice the use of the `@Primary` annotation on the plain `RestTemplateBuilder` declaration in the preceding example to disambiguate the unqualified `@Autowired` injection. + + [[rest-client-loadbalancer-client]] == Spring RestClient as a LoadBalancer Client @@ -256,7 +339,7 @@ IMPORTANT: To use it, add xref:spring-cloud-commons/loadbalancer.adoc#spring-clo === Multiple `RestClient.Builder` Objects If you want a `RestClient.Builder` that is not load-balanced, create a `RestClient.Builder` bean and inject it. -To access the load-balanced `RestClient`, use the `@LoadBalanced` qualifier when you create your `@Bean`, as the following example shows: +To access the load-balanced `RestClient.Builder`, use the `@LoadBalanced` qualifier when you create your `@Bean`, as the following example shows: [source,java,indent=0] ---- @@ -296,7 +379,7 @@ public class MyClass { } ---- -IMPORTANT: Notice the use of the `@Primary` annotation on the plain `RestTemplate` declaration in the preceding example to disambiguate the unqualified `@Autowired` injection. +IMPORTANT: Notice the use of the `@Primary` annotation on the plain `RestClient.Builder` declaration in the preceding example to disambiguate the unqualified `@Autowired` injection. [[webclinet-loadbalancer-client]] == Spring WebClient as a LoadBalancer Client diff --git a/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/AbstractLoadBalancerBlockingBuilderBeanPostProcessor.java b/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/AbstractLoadBalancerBlockingBuilderBeanPostProcessor.java new file mode 100644 index 000000000..89de23773 --- /dev/null +++ b/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/AbstractLoadBalancerBlockingBuilderBeanPostProcessor.java @@ -0,0 +1,66 @@ +/* + * Copyright 2012-2024 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.client.loadbalancer; + +import org.springframework.beans.BeansException; +import org.springframework.beans.factory.ObjectProvider; +import org.springframework.beans.factory.config.BeanPostProcessor; +import org.springframework.context.ApplicationContext; +import org.springframework.http.client.ClientHttpRequestInterceptor; + +/** + * A {@link BeanPostProcessor} that adds the provided {@link ClientHttpRequestInterceptor} + * to bean instances annotated with {@link LoadBalanced}. + * + * @author Olga Maciaszek-Sharma + * @since 4.2.0 + */ +public abstract class AbstractLoadBalancerBlockingBuilderBeanPostProcessor + implements BeanPostProcessor { + + protected final ObjectProvider loadBalancerInterceptorProvider; + + protected final ApplicationContext context; + + AbstractLoadBalancerBlockingBuilderBeanPostProcessor(ObjectProvider loadBalancerInterceptorProvider, + ApplicationContext context) { + this.loadBalancerInterceptorProvider = loadBalancerInterceptorProvider; + this.context = context; + } + + @Override + public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { + // a separate call to verify supported type before searching for annotation for + // performance reasons + if (isSupported(bean)) { + if (context.findAnnotationOnBean(beanName, LoadBalanced.class) == null) { + return bean; + } + ClientHttpRequestInterceptor interceptor = loadBalancerInterceptorProvider.getIfAvailable(); + if (interceptor == null) { + throw new IllegalStateException(ClientHttpRequestInterceptor.class.getSimpleName() + " not available."); + } + bean = apply(bean, interceptor); + } + return bean; + } + + protected abstract Object apply(Object bean, ClientHttpRequestInterceptor interceptor); + + protected abstract boolean isSupported(Object bean); + +} diff --git a/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerAutoConfiguration.java b/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerAutoConfiguration.java index 877f674aa..6f7ed529d 100644 --- a/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerAutoConfiguration.java +++ b/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerAutoConfiguration.java @@ -101,6 +101,15 @@ static LoadBalancerRestClientBuilderBeanPostProcessor(loadBalancerInterceptorProvider, context); } + @Bean + @ConditionalOnBean(DeferringLoadBalancerInterceptor.class) + @ConditionalOnMissingBean(LoadBalancerRestTemplateBuilderBeanPostProcessor.class) + static LoadBalancerRestTemplateBuilderBeanPostProcessor lbRestTemplateBuilderPostProcessor( + ObjectProvider loadBalancerInterceptorProvider, + ApplicationContext context) { + return new LoadBalancerRestTemplateBuilderBeanPostProcessor<>(loadBalancerInterceptorProvider, context); + } + } @AutoConfiguration diff --git a/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerRestClientBuilderBeanPostProcessor.java b/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerRestClientBuilderBeanPostProcessor.java index 0e4bfe646..0fae7807c 100644 --- a/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerRestClientBuilderBeanPostProcessor.java +++ b/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerRestClientBuilderBeanPostProcessor.java @@ -16,63 +16,57 @@ package org.springframework.cloud.client.loadbalancer; -import org.springframework.beans.BeansException; import org.springframework.beans.factory.ObjectProvider; -import org.springframework.beans.factory.config.BeanPostProcessor; import org.springframework.context.ApplicationContext; import org.springframework.http.client.ClientHttpRequestInterceptor; import org.springframework.web.client.RestClient; /** - * A {@link BeanPostProcessor} that adds the provided {@link ClientHttpRequestInterceptor} - * to all {@link RestClient.Builder} instances annotated with {@link LoadBalanced}. + * {@link RestClient.Builder}-specific + * {@link AbstractLoadBalancerBlockingBuilderBeanPostProcessor} implementation. Adds the + * provided {@link ClientHttpRequestInterceptor} to all {@link RestClient.Builder} + * instances annotated with {@link LoadBalanced}. * * @author Olga Maciaszek-Sharma * @since 4.1.0 */ public class LoadBalancerRestClientBuilderBeanPostProcessor - implements BeanPostProcessor { - - private final ObjectProvider loadBalancerInterceptorProvider; - - private final ApplicationContext context; + extends AbstractLoadBalancerBlockingBuilderBeanPostProcessor { /** - * Creates a {@link LoadBalancerRestClientBuilderBeanPostProcessor} instance using a provided {@link ClientHttpRequestInterceptor} and application context. - * @param loadBalancerInterceptor a {@link ClientHttpRequestInterceptor} used for load-balancing + * Creates a {@link LoadBalancerRestClientBuilderBeanPostProcessor} instance using a + * provided {@link ClientHttpRequestInterceptor} and application context. + * @param loadBalancerInterceptor a {@link ClientHttpRequestInterceptor} used for + * load-balancing * @param context {@link ApplicationContext} - * @deprecated in favour of {@link LoadBalancerRestClientBuilderBeanPostProcessor#LoadBalancerRestClientBuilderBeanPostProcessor(ObjectProvider, ApplicationContext)} + * @deprecated in favour of + * {@link LoadBalancerRestClientBuilderBeanPostProcessor#LoadBalancerRestClientBuilderBeanPostProcessor(ObjectProvider, ApplicationContext)} */ @Deprecated(forRemoval = true) public LoadBalancerRestClientBuilderBeanPostProcessor(T loadBalancerInterceptor, ApplicationContext context) { - this.loadBalancerInterceptorProvider = new SimpleObjectProvider<>(loadBalancerInterceptor); - this.context = context; + this(new SimpleObjectProvider<>(loadBalancerInterceptor), context); } /** - * Creates a {@link LoadBalancerRestClientBuilderBeanPostProcessor} instance using interceptor {@link ObjectProvider} and application context. - * @param loadBalancerInterceptorProvider an {@link ObjectProvider} for {@link ClientHttpRequestInterceptor} used for load-balancing + * Creates a {@link LoadBalancerRestClientBuilderBeanPostProcessor} instance using + * interceptor {@link ObjectProvider} and application context. + * @param loadBalancerInterceptorProvider an {@link ObjectProvider} for + * {@link ClientHttpRequestInterceptor} used for load-balancing * @param context {@link ApplicationContext} */ public LoadBalancerRestClientBuilderBeanPostProcessor(ObjectProvider loadBalancerInterceptorProvider, ApplicationContext context) { - this.loadBalancerInterceptorProvider = loadBalancerInterceptorProvider; - this.context = context; + super(loadBalancerInterceptorProvider, context); + } + + @Override + protected Object apply(Object bean, ClientHttpRequestInterceptor interceptor) { + return ((RestClient.Builder) bean).requestInterceptor(interceptor); } @Override - public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { - if (bean instanceof RestClient.Builder) { - if (context.findAnnotationOnBean(beanName, LoadBalanced.class) == null) { - return bean; - } - ClientHttpRequestInterceptor interceptor = loadBalancerInterceptorProvider.getIfAvailable(); - if (interceptor == null) { - throw new IllegalStateException(ClientHttpRequestInterceptor.class.getSimpleName() + " not available."); - } - ((RestClient.Builder) bean).requestInterceptor(interceptor); - } - return bean; + protected boolean isSupported(Object bean) { + return bean instanceof RestClient.Builder; } } diff --git a/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerRestTemplateBuilderBeanPostProcessor.java b/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerRestTemplateBuilderBeanPostProcessor.java new file mode 100644 index 000000000..5dc46d11f --- /dev/null +++ b/spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerRestTemplateBuilderBeanPostProcessor.java @@ -0,0 +1,51 @@ +/* + * Copyright 2012-2024 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.client.loadbalancer; + +import org.springframework.beans.factory.ObjectProvider; +import org.springframework.boot.web.client.RestTemplateBuilder; +import org.springframework.context.ApplicationContext; +import org.springframework.http.client.ClientHttpRequestInterceptor; + +/** + * {@link RestTemplateBuilder}-specific + * {@link AbstractLoadBalancerBlockingBuilderBeanPostProcessor} implementation. Adds the + * provided {@link ClientHttpRequestInterceptor} to all {@link RestTemplateBuilder} + * instances annotated with {@link LoadBalanced}. + * + * @author Olga Maciaszek-Sharma + * @since 4.2.0 + */ +public class LoadBalancerRestTemplateBuilderBeanPostProcessor + extends AbstractLoadBalancerBlockingBuilderBeanPostProcessor { + + public LoadBalancerRestTemplateBuilderBeanPostProcessor(ObjectProvider loadBalancerInterceptorProvider, + ApplicationContext context) { + super(loadBalancerInterceptorProvider, context); + } + + @Override + protected boolean isSupported(Object bean) { + return bean instanceof RestTemplateBuilder; + } + + @Override + protected Object apply(Object bean, ClientHttpRequestInterceptor interceptor) { + return ((RestTemplateBuilder) bean).interceptors(interceptor); + } + +} diff --git a/spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/LoadBalancedRestClientIntegrationTests.java b/spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/LoadBalancedRestClientIntegrationTests.java index 20e528e44..a833dbcb3 100644 --- a/spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/LoadBalancedRestClientIntegrationTests.java +++ b/spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/LoadBalancedRestClientIntegrationTests.java @@ -16,7 +16,6 @@ package org.springframework.cloud.client.loadbalancer; -import java.io.IOException; import java.net.URI; import org.junit.jupiter.api.Test; @@ -25,7 +24,6 @@ import org.springframework.boot.SpringBootConfiguration; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.cloud.client.ServiceInstance; -import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.Bean; import org.springframework.web.client.RestClient; @@ -41,17 +39,16 @@ properties = "spring.cloud.loadbalancer.retry.enabled=false") public class LoadBalancedRestClientIntegrationTests { - private final RestClient client; + private final RestClient.Builder restClientBuilder; - @Autowired - ApplicationContext context; - - public LoadBalancedRestClientIntegrationTests(@Autowired RestClient.Builder clientBuilder) { - this.client = clientBuilder.build(); + public LoadBalancedRestClientIntegrationTests(@Autowired RestClient.Builder restClientBuilder) { + this.restClientBuilder = restClientBuilder; } @Test void shouldBuildLoadBalancedRestClientInConstructor() { + RestClient client = restClientBuilder.build(); + // Interceptors are not visible in RestClient assertThatThrownBy(() -> client.get().uri("http://test-service").retrieve()) .hasMessage("LoadBalancerInterceptor invoked."); @@ -70,13 +67,13 @@ RestClient.Builder restClientBuilder() { LoadBalancerClient testLoadBalancerClient() { return new LoadBalancerClient() { @Override - public T execute(String serviceId, LoadBalancerRequest request) throws IOException { + public T execute(String serviceId, LoadBalancerRequest request) { throw new UnsupportedOperationException("LoadBalancerInterceptor invoked."); } @Override - public T execute(String serviceId, ServiceInstance serviceInstance, LoadBalancerRequest request) - throws IOException { + public T execute(String serviceId, ServiceInstance serviceInstance, + LoadBalancerRequest request) { throw new UnsupportedOperationException("LoadBalancerInterceptor invoked."); } diff --git a/spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/LoadBalancedRestTemplateBuilderIntegrationTests.java b/spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/LoadBalancedRestTemplateBuilderIntegrationTests.java new file mode 100644 index 000000000..8613c4865 --- /dev/null +++ b/spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/LoadBalancedRestTemplateBuilderIntegrationTests.java @@ -0,0 +1,101 @@ +/* + * Copyright 2012-2024 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.client.loadbalancer; + +import java.net.URI; + +import org.junit.jupiter.api.Test; + +import org.springframework.beans.factory.annotation.Autowired; +import org.springframework.boot.SpringBootConfiguration; +import org.springframework.boot.test.context.SpringBootTest; +import org.springframework.boot.web.client.RestTemplateBuilder; +import org.springframework.cloud.client.ServiceInstance; +import org.springframework.context.annotation.Bean; +import org.springframework.web.client.RestTemplate; + +import static org.assertj.core.api.Assertions.assertThat; + +/** + * Integration tests for load-balanced {@link RestTemplateBuilder}. + * + * @author Olga Maciaszek-Sharma + */ +@SpringBootTest(classes = { LoadBalancedRestTemplateBuilderIntegrationTests.TestConfig.class, + LoadBalancerAutoConfiguration.class }, properties = "spring.cloud.loadbalancer.retry.enabled=false") +public class LoadBalancedRestTemplateBuilderIntegrationTests { + + private final RestTemplateBuilder restTemplateBuilder; + + public LoadBalancedRestTemplateBuilderIntegrationTests(@Autowired RestTemplateBuilder restTemplateBuilder) { + this.restTemplateBuilder = restTemplateBuilder; + } + + @Test + void shouldBuildLoadBalancedRestTemplate() { + RestTemplate restTemplate = restTemplateBuilder.build(); + + assertThat(restTemplate.getInterceptors()).hasSize(1); + assertThat(restTemplate.getInterceptors().get(0)).isInstanceOf(DeferringLoadBalancerInterceptor.class); + assertThat(((DeferringLoadBalancerInterceptor) restTemplate.getInterceptors().get(0)) + .getLoadBalancerInterceptorProvider() + .getObject()).isInstanceOf(BlockingLoadBalancerInterceptor.class); + } + + @SpringBootConfiguration + static class TestConfig { + + @LoadBalanced + @Bean + RestTemplateBuilder restTemplateBuilder() { + return new RestTemplateBuilder(); + } + + @Bean + LoadBalancerClient testLoadBalancerClient() { + return new LoadBalancerClient() { + @Override + public T execute(String serviceId, LoadBalancerRequest request) { + throw new UnsupportedOperationException("LoadBalancerInterceptor invoked."); + } + + @Override + public T execute(String serviceId, ServiceInstance serviceInstance, + LoadBalancerRequest request) { + throw new UnsupportedOperationException("LoadBalancerInterceptor invoked."); + } + + @Override + public URI reconstructURI(ServiceInstance instance, URI original) { + throw new UnsupportedOperationException("LoadBalancerInterceptor invoked."); + } + + @Override + public ServiceInstance choose(String serviceId) { + throw new UnsupportedOperationException("LoadBalancerInterceptor invoked."); + } + + @Override + public ServiceInstance choose(String serviceId, Request request) { + throw new UnsupportedOperationException("LoadBalancerInterceptor invoked."); + } + }; + } + + } + +}