@LoadBalanced RestClient (#1294)
This commit is contained in:
Olga Maciaszek-Sharma
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dd47ca6c29
@@ -135,7 +135,7 @@ Please see the documentation of the `ServiceRegistry` implementation you use for
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For instance, Eureka's supported statuses are `UP`, `DOWN`, `OUT_OF_SERVICE`, and `UNKNOWN`.
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[[rest-template-loadbalancer-client]]
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== Spring RestTemplate as a Load Balancer Client
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== Spring `RestTemplate` as a LoadBalancer Client
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You can configure a `RestTemplate` to use a Load-balancer client.
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To create a load-balanced `RestTemplate`, create a `RestTemplate` `@Bean` and use the `@LoadBalanced` qualifier, as the following example shows:
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@@ -157,8 +157,8 @@ public class MyClass {
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private RestTemplate restTemplate;
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public String doOtherStuff() {
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String results = restTemplate.getForObject("http://stores/stores", String.class);
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return results;
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String result = restTemplate.getForObject("http://stores/stores", String.class);
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return result;
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}
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}
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----
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@@ -167,13 +167,140 @@ CAUTION: A `RestTemplate` bean is no longer created through auto-configuration.
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Individual applications must create it.
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The URI needs to use a virtual host name (that is, a service name, not a host name).
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The BlockingLoadBalancerClient is used to create a full physical address.
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The `BlockingLoadBalancerClient` is used to create a full physical address.
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IMPORTANT: To use a load-balanced `RestTemplate`, you need to have a load-balancer implementation in your classpath.
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IMPORTANT: To use a load-balanced `RestTemplate`, you need to have a Spring Cloud LoadBalancer implementation in your classpath.
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Add xref:spring-cloud-commons/loadbalancer.adoc#spring-cloud-loadbalancer-starter[Spring Cloud LoadBalancer starter] to your project in order to use it.
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[[multiple-resttemplate-objects]]
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=== Multiple `RestTemplate` Objects
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If you want a `RestTemplate` that is not load-balanced, create a `RestTemplate` bean and inject it.
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To access the load-balanced `RestTemplate`, use the `@LoadBalanced` qualifier when you create your `@Bean`, as the following example shows:
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[source,java,indent=0]
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----
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@Configuration
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public class MyConfiguration {
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@LoadBalanced
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@Bean
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RestTemplate loadBalanced() {
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return new RestTemplate();
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}
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@Primary
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@Bean
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RestTemplate restTemplate() {
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return new RestTemplate();
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}
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}
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public class MyClass {
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@Autowired
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private RestTemplate restTemplate;
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@Autowired
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@LoadBalanced
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private RestTemplate loadBalanced;
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public String doOtherStuff() {
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return loadBalanced.getForObject("http://stores/stores", String.class);
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}
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public String doStuff() {
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return restTemplate.getForObject("http://example.com", String.class);
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}
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}
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----
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IMPORTANT: Notice the use of the `@Primary` annotation on the plain `RestTemplate` declaration in the preceding example to disambiguate the unqualified `@Autowired` injection.
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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`.
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[[rest-client-loadbalancer-client]]
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== Spring `RestClient` as a LoadBalancer Client
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You can configure a `RestClient` to use a Load-balancer client.
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To create a load-balanced `RestClient`, create a `RestClient.Builder` `@Bean` and use the `@LoadBalanced` qualifier, as the following example shows:
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[source,java,indent=0]
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----
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@Configuration
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public class MyConfiguration {
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@LoadBalanced
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@Bean
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RestClient.Builder restClientBuilder() {
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return RestClient.builder();
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}
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}
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public class MyClass {
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@Autowired
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private RestClient.Builder restClientBuilder;
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public String doOtherStuff() {
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return restClientBuilder.build().get().uri(URI.create("http://stores/stores")).retrieve().body(String.class);
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}
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}
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----
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The URI needs to use a virtual host name (that is, a service name, not a host name).
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The `BlockingLoadBalancerClient` is used to create a full physical address.
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IMPORTANT: To use a load-balanced `RestClient`, you need to have a Spring LoadBalancer implementation in your classpath.
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Add xref:spring-cloud-commons/loadbalancer.adoc#spring-cloud-loadbalancer-starter[Spring Cloud LoadBalancer starter] to your project in order to use it.
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[[multiple-restclient-objects]]
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=== Multiple `RestClient.Builder` Objects
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If you want a `RestClient.Builder` that is not load-balanced, create a `RestClient.Builder` bean and inject it.
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To access the load-balanced `RestClient`, use the `@LoadBalanced` qualifier when you create your `@Bean`, as the following example shows:
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[source,java,indent=0]
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----
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@Configuration
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public class MyConfiguration {
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@LoadBalanced
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@Bean
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RestClient.Builder loadBalanced() {
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return RestClient.builder();
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}
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@Primary
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@Bean
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RestClient.Builder restClientBuilder() {
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return WebClient.builder();
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}
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}
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public class MyClass {
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@Autowired
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private RestClient.Builder restClientBuilder;
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@Autowired
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@LoadBalanced
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private RestClient.Builder loadBalanced;
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public String doOtherStuff() {
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return restClientBuilder.build().get().uri("http://stores/stores")
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.retrieve().body(String.class);
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}
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public String doStuff() {
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return restClientBuilder.build().get().uri("http://example.com")
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.retrieve().body(String.class);
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}
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}
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----
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IMPORTANT: Notice the use of the `@Primary` annotation on the plain `RestTemplate` declaration in the preceding example to disambiguate the unqualified `@Autowired` injection.
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[[webclinet-loadbalancer-client]]
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== Spring WebClient as a Load Balancer Client
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== Spring `WebClient` as a LoadBalancer Client
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You can configure `WebClient` to automatically use a load-balancer client.
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To create a load-balanced `WebClient`, create a `WebClient.Builder` `@Bean` and use the `@LoadBalanced` qualifier, as follows:
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@@ -204,11 +331,55 @@ public class MyClass {
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The URI needs to use a virtual host name (that is, a service name, not a host name).
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The Spring Cloud LoadBalancer is used to create a full physical address.
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IMPORTANT: If you want to use a `@LoadBalanced WebClient.Builder`, you need to have a load balancer
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IMPORTANT: If you want to use a `@LoadBalanced WebClient.Builder`, you need to have a Spring Cloud LoadBalancer
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implementation in the classpath. We recommend that you add the
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xref:spring-cloud-commons/loadbalancer.adoc#spring-cloud-loadbalancer-starter[Spring Cloud LoadBalancer starter] to your project.
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Then, `ReactiveLoadBalancer` is used underneath.
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[[multiple-webclient-objects]]
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=== Multiple `WebClient.Builder` Objects
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If you want a `WebClient.Buider` that is not load-balanced, create a `WebClient` bean and inject it.
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To access the load-balanced `WebClient.Builder`, use the `@LoadBalanced` qualifier when you create your `@Bean`, as the following example shows:
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[source,java,indent=0]
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----
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@Configuration
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public class MyConfiguration {
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@LoadBalanced
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@Bean
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WebClient.Builder loadBalanced() {
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return WebClient.builder();
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}
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@Primary
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@Bean
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WebClient.Builder webClientBuilder() {
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return WebClient.builder();
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}
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}
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public class MyClass {
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@Autowired
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private WebClient.Builder webClientBuilder;
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@Autowired
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@LoadBalanced
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private WebClient.Builder loadBalanced;
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public Mono<String> doOtherStuff() {
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return loadBalanced.build().get().uri("http://stores/stores")
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.retrieve().bodyToMono(String.class);
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}
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public Mono<String> doStuff() {
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return webClientBuilder.build().get().uri("http://example.com")
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.retrieve().bodyToMono(String.class);
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}
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}
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----
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[[retrying-failed-requests]]
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=== Retrying Failed Requests
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@@ -295,96 +466,6 @@ public class MyConfiguration {
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}
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----
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[[multiple-resttemplate-objects]]
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== Multiple `RestTemplate` Objects
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If you want a `RestTemplate` that is not load-balanced, create a `RestTemplate` bean and inject it.
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To access the load-balanced `RestTemplate`, use the `@LoadBalanced` qualifier when you create your `@Bean`, as the following example shows:
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[source,java,indent=0]
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----
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@Configuration
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public class MyConfiguration {
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@LoadBalanced
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@Bean
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RestTemplate loadBalanced() {
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return new RestTemplate();
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}
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@Primary
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@Bean
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RestTemplate restTemplate() {
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return new RestTemplate();
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}
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}
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public class MyClass {
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@Autowired
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private RestTemplate restTemplate;
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@Autowired
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@LoadBalanced
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private RestTemplate loadBalanced;
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public String doOtherStuff() {
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return loadBalanced.getForObject("http://stores/stores", String.class);
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}
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public String doStuff() {
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return restTemplate.getForObject("http://example.com", String.class);
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}
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}
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----
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IMPORTANT: Notice the use of the `@Primary` annotation on the plain `RestTemplate` declaration in the preceding example to disambiguate the unqualified `@Autowired` injection.
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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`.
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[[multiple-webclient-objects]]
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== Multiple WebClient Objects
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If you want a `WebClient` that is not load-balanced, create a `WebClient` bean and inject it.
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To access the load-balanced `WebClient`, use the `@LoadBalanced` qualifier when you create your `@Bean`, as the following example shows:
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[source,java,indent=0]
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----
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@Configuration
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public class MyConfiguration {
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@LoadBalanced
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@Bean
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WebClient.Builder loadBalanced() {
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return WebClient.builder();
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}
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@Primary
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@Bean
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WebClient.Builder webClient() {
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return WebClient.builder();
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}
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}
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public class MyClass {
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@Autowired
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private WebClient.Builder webClientBuilder;
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@Autowired
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@LoadBalanced
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private WebClient.Builder loadBalanced;
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public Mono<String> doOtherStuff() {
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return loadBalanced.build().get().uri("http://stores/stores")
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.retrieve().bodyToMono(String.class);
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}
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public Mono<String> doStuff() {
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return webClientBuilder.build().get().uri("http://example.com")
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.retrieve().bodyToMono(String.class);
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}
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}
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----
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[[loadbalanced-webclient]]
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== Spring WebFlux `WebClient` as a Load Balancer Client
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@@ -44,12 +44,13 @@ NOTE: The classes you pass as `@LoadBalancerClient` or `@LoadBalancerClients` co
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[[spring-cloud-loadbalancer-integrations]]
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== Spring Cloud LoadBalancer integrations
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In order to make it easy to use Spring Cloud LoadBalancer, we provide `ReactorLoadBalancerExchangeFilterFunction` that can be used with `WebClient` and `BlockingLoadBalancerClient` that works with `RestTemplate`.
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In order to make it easy to use Spring Cloud LoadBalancer, we provide `ReactorLoadBalancerExchangeFilterFunction` that can be used with `WebClient` and `BlockingLoadBalancerClient` that works with `RestTemplate` and `RestClient`.
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You can see more information and examples of usage in the following sections:
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* xref:spring-cloud-commons/common-abstractions.adoc#rest-template-loadbalancer-client[Spring RestTemplate as a Load Balancer Client]
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* xref:spring-cloud-commons/common-abstractions.adoc#webclinet-loadbalancer-client[Spring WebClient as a Load Balancer Client]
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* xref:spring-cloud-commons/common-abstractions.adoc#webflux-with-reactive-loadbalancer[Spring WebFlux WebClient with `ReactorLoadBalancerExchangeFilterFunction`]
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* xref:spring-cloud-commons/common-abstractions.adoc#rest-template-loadbalancer-client[Spring `RestTemplate` as a LoadBalancer Client]
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* xref:spring-cloud-commons/common-abstractions.adoc#rest-client-loadbalancer-client[Spring `RestClient` as a LoadBalancer Client]
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* xref:spring-cloud-commons/common-abstractions.adoc#webclinet-loadbalancer-client[Spring `WebClient` as a LoadBalancer Client]
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* xref:spring-cloud-commons/common-abstractions.adoc#webflux-with-reactive-loadbalancer[Spring `WebFlux WebClient` with `ReactorLoadBalancerExchangeFilterFunction`]
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[[loadbalancer-caching]]
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== Spring Cloud LoadBalancer Caching
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@@ -232,7 +233,7 @@ public class CustomLoadBalancerConfiguration {
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----
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TIP: For the non-reactive stack, create this supplier with the `withBlockingHealthChecks()`.
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You can also pass your own `WebClient` or `RestTemplate` instance to be used for the checks.
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You can also pass your own `WebClient`, `RestTemplate` or `RestClient` instance to be used for the checks.
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WARNING: `HealthCheckServiceInstanceListSupplier` has its own caching mechanism based on Reactor Flux `replay()`. Therefore, if it's being used, you may want to skip wrapping that supplier with `CachingServiceInstanceListSupplier`.
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@@ -336,7 +337,7 @@ public class CustomLoadBalancerConfiguration {
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You can use the selected `ServiceInstance` to transform the load-balanced HTTP Request.
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For `RestTemplate`, you need to implement and define `LoadBalancerRequestTransformer` as follows:
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For `RestTemplate` and `RestClient`, you need to implement and define `LoadBalancerRequestTransformer` as follows:
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[source,java,indent=0]
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----
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