Add retry support for blocking LoadBalancer (#832)

* Add LoadBalancerProperties and BlockingLoadBalancedRetryPolicy. Add spring-retry dependency in LoadBalancer.

* Add BlockingLoadBalancedRetryFactory

* Move retry properties to LoadBalancerRetryProperties.

* Refactor and remove deprecations, fix checkstyle.

* Add BlockingLoadBalancedRetryPolicy to autoconfiguration. Set default retryableStatusCode prop. Fix javadoc.

* Allow using @Order on LoadBalancedRetryFactory beans.

* Add tests. Reformat tests. Add explanatory comments.

* Add documentation.

* Fix javadoc.

* Fix docs after review.

* Change field name.

docs/src/main/asciidoc/_configprops.adoc

@@ -35,6 +35,10 @@
 |spring.cloud.loadbalancer.health-check.interval | 25s | Interval for rerunning the HealthCheck scheduler.
 |spring.cloud.loadbalancer.health-check.path |  | 
 |spring.cloud.loadbalancer.retry.enabled | true | 
+|spring.cloud.loadbalancer.retry.max-retries-on-next-service-instance | 1 | Number of retries to be executed on the next <code>ServiceInstance</code>. A <code>ServiceInstance</code> is chosen before each retry call.
+|spring.cloud.loadbalancer.retry.max-retries-on-same-service-instance | 0 | Number of retries to be executed on the same <code>ServiceInstance</code>.
+|spring.cloud.loadbalancer.retry.retry-on-all-operations | false | Indicates retries should be attempted on operations other than {@link HttpMethod#GET}.
+|spring.cloud.loadbalancer.retry.retryable-status-codes |  | A {@link Set} of status codes that should trigger a retry.
 |spring.cloud.loadbalancer.ribbon.enabled | true | Causes `RibbonLoadBalancerClient` to be used by default.
 |spring.cloud.loadbalancer.service-discovery.timeout |  | String representation of Duration of the timeout for calls to service discovery.
 |spring.cloud.loadbalancer.zone |  | Spring Cloud LoadBalancer zone.

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

@@ -453,12 +453,27 @@ set the `spring.cloud.loadbalancer.ribbon.enabled` property to `false`.
 A load-balanced `RestTemplate` can be configured to retry failed requests.
 By default, this logic is disabled.
 You can enable it by adding link:https://github.com/spring-projects/spring-retry[Spring Retry] to your application's classpath.
-The load-balanced `RestTemplate` honors some of the Ribbon configuration values related to retrying failed requests.
-You can use `client.ribbon.MaxAutoRetries`, `client.ribbon.MaxAutoRetriesNextServer`, and `client.ribbon.OkToRetryOnAllOperations` properties.
+
 If you would like to disable the retry logic with Spring Retry on the classpath, you can set `spring.cloud.loadbalancer.retry.enabled=false`.
+
+If you would like to implement a `BackOffPolicy` in your retries, you need to create a bean of type `LoadBalancedRetryFactory` and override the `createBackOffPolicy()` method.
+
+===== Ribbon-based retries
+
+For the Ribbon-backed implementation, the load-balanced `RestTemplate` honors some of the Ribbon configuration values related to retrying failed requests.
+You can use the `client.ribbon.MaxAutoRetries`, `client.ribbon.MaxAutoRetriesNextServer`, and `client.ribbon.OkToRetryOnAllOperations` properties.
+
 See the https://github.com/Netflix/ribbon/wiki/Getting-Started#the-properties-file-sample-clientproperties[Ribbon documentation] for a description of what these properties do.
 
-If you would like to implement a `BackOffPolicy` in your retries, you need to create a bean of type `LoadBalancedRetryFactory` and override the `createBackOffPolicy` method:
+===== Spring Cloud LoadBalancer-based retries
+
+For the Spring Cloud LoadBalancer-backed implementation, you can set:
+
+- `spring.cloud.loadbalancer.retry.maxRetriesOnSameServiceInstance` - indicates how many times a request should be retried on the same `ServiceInstance` (counted separately for every selected instance)
+- `spring.cloud.loadbalancer.retry.maxRetriesOnNextServiceInstance` - indicates how many times a request should be retried a newly selected `ServiceInstance`
+- `spring.cloud.loadbalancer.retry.retryableStatusCodes` - the status codes on which to always retry a failed request.
+
+WARN:: If you chose to override the `LoadBalancedRetryFactory` while using the Spring Cloud LoadBalancer-backed approach, make sure you annotate your bean with `@Order` and set it to a higher precedence than `1000`, which is the order set on the `BlockingLoadBalancedRetryFactory`.
 
 ====
 [source,java,indent=0]

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/InterceptorRetryPolicy.java

@@ -28,13 +28,13 @@ import org.springframework.retry.RetryPolicy;
  */
 public class InterceptorRetryPolicy implements RetryPolicy {
 
-	private HttpRequest request;
+	private final HttpRequest request;
 
-	private LoadBalancedRetryPolicy policy;
+	private final LoadBalancedRetryPolicy policy;
 
-	private ServiceInstanceChooser serviceInstanceChooser;
+	private final ServiceInstanceChooser serviceInstanceChooser;
 
-	private String serviceName;
+	private final String serviceName;
 
 	/**
 	 * Creates a new retry policy.
@@ -56,21 +56,20 @@ public class InterceptorRetryPolicy implements RetryPolicy {
 		LoadBalancedRetryContext lbContext = (LoadBalancedRetryContext) context;
 		if (lbContext.getRetryCount() == 0 && lbContext.getServiceInstance() == null) {
 			// We haven't even tried to make the request yet so return true so we do
-			lbContext.setServiceInstance(
-					this.serviceInstanceChooser.choose(this.serviceName));
+			lbContext.setServiceInstance(serviceInstanceChooser.choose(serviceName));
 			return true;
 		}
-		return this.policy.canRetryNextServer(lbContext);
+		return policy.canRetryNextServer(lbContext);
 	}
 
 	@Override
 	public RetryContext open(RetryContext parent) {
-		return new LoadBalancedRetryContext(parent, this.request);
+		return new LoadBalancedRetryContext(parent, request);
 	}
 
 	@Override
 	public void close(RetryContext context) {
-		this.policy.close((LoadBalancedRetryContext) context);
+		policy.close((LoadBalancedRetryContext) context);
 	}
 
 	@Override
@@ -80,7 +79,7 @@ public class InterceptorRetryPolicy implements RetryPolicy {
 		// increases the retry count
 		lbContext.registerThrowable(throwable);
 		// let the policy know about the exception as well
-		this.policy.registerThrowable(lbContext, throwable);
+		policy.registerThrowable(lbContext, throwable);
 	}
 
 	@Override
@@ -94,25 +93,25 @@ public class InterceptorRetryPolicy implements RetryPolicy {
 
 		InterceptorRetryPolicy that = (InterceptorRetryPolicy) o;
 
-		if (!this.request.equals(that.request)) {
+		if (!request.equals(that.request)) {
 			return false;
 		}
-		if (!this.policy.equals(that.policy)) {
+		if (!policy.equals(that.policy)) {
 			return false;
 		}
-		if (!this.serviceInstanceChooser.equals(that.serviceInstanceChooser)) {
+		if (!serviceInstanceChooser.equals(that.serviceInstanceChooser)) {
 			return false;
 		}
-		return this.serviceName.equals(that.serviceName);
+		return serviceName.equals(that.serviceName);
 
 	}
 
 	@Override
 	public int hashCode() {
-		int result = this.request.hashCode();
-		result = 31 * result + this.policy.hashCode();
-		result = 31 * result + this.serviceInstanceChooser.hashCode();
-		result = 31 * result + this.serviceName.hashCode();
+		int result = request.hashCode();
+		result = 31 * result + policy.hashCode();
+		result = 31 * result + serviceInstanceChooser.hashCode();
+		result = 31 * result + serviceName.hashCode();
 		return result;
 	}
 

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerAutoConfiguration.java

@@ -30,12 +30,13 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingClas
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.AnnotationAwareOrderComparator;
 import org.springframework.http.client.ClientHttpRequestInterceptor;
 import org.springframework.retry.support.RetryTemplate;
 import org.springframework.web.client.RestTemplate;
 
 /**
- * Auto-configuration for Ribbon (client-side load balancing).
+ * Auto-configuration for blocking client-side load balancing.
  *
  * @author Spencer Gibb
  * @author Dave Syer
@@ -79,7 +80,7 @@ public class LoadBalancerAutoConfiguration {
 	static class LoadBalancerInterceptorConfig {
 
 		@Bean
-		public LoadBalancerInterceptor ribbonInterceptor(
+		public LoadBalancerInterceptor loadBalancerInterceptor(
 				LoadBalancerClient loadBalancerClient,
 				LoadBalancerRequestFactory requestFactory) {
 			return new LoadBalancerInterceptor(loadBalancerClient, requestFactory);
@@ -124,13 +125,14 @@ public class LoadBalancerAutoConfiguration {
 
 		@Bean
 		@ConditionalOnMissingBean
-		public RetryLoadBalancerInterceptor ribbonInterceptor(
+		public RetryLoadBalancerInterceptor loadBalancerRetryInterceptor(
 				LoadBalancerClient loadBalancerClient,
 				LoadBalancerRetryProperties properties,
 				LoadBalancerRequestFactory requestFactory,
-				LoadBalancedRetryFactory loadBalancedRetryFactory) {
+				List<LoadBalancedRetryFactory> loadBalancedRetryFactories) {
+			AnnotationAwareOrderComparator.sort(loadBalancedRetryFactories);
 			return new RetryLoadBalancerInterceptor(loadBalancerClient, properties,
-					requestFactory, loadBalancedRetryFactory);
+					requestFactory, loadBalancedRetryFactories.get(0));
 		}
 
 		@Bean

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerRetryProperties.java

@@ -16,7 +16,11 @@
 
 package org.springframework.cloud.client.loadbalancer;
 
+import java.util.HashSet;
+import java.util.Set;
+
 import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.http.HttpMethod;
 
 /**
  * Configuration properties for the {@link LoadBalancerClient}.
@@ -28,6 +32,28 @@ public class LoadBalancerRetryProperties {
 
 	private boolean enabled = true;
 
+	/**
+	 * Indicates retries should be attempted on operations other than
+	 * {@link HttpMethod#GET}.
+	 */
+	private boolean retryOnAllOperations = false;
+
+	/**
+	 * Number of retries to be executed on the same <code>ServiceInstance</code>.
+	 */
+	private int maxRetriesOnSameServiceInstance = 0;
+
+	/**
+	 * Number of retries to be executed on the next <code>ServiceInstance</code>. A
+	 * <code>ServiceInstance</code> is chosen before each retry call.
+	 */
+	private int maxRetriesOnNextServiceInstance = 1;
+
+	/**
+	 * A {@link Set} of status codes that should trigger a retry.
+	 */
+	private Set<Integer> retryableStatusCodes = new HashSet<>();
+
 	/**
 	 * Returns true if the load balancer should retry failed requests.
 	 * @return True if the load balancer should retry failed requests; false otherwise.
@@ -44,4 +70,36 @@ public class LoadBalancerRetryProperties {
 		this.enabled = enabled;
 	}
 
+	public boolean isRetryOnAllOperations() {
+		return retryOnAllOperations;
+	}
+
+	public void setRetryOnAllOperations(boolean retryOnAllOperations) {
+		this.retryOnAllOperations = retryOnAllOperations;
+	}
+
+	public int getMaxRetriesOnSameServiceInstance() {
+		return maxRetriesOnSameServiceInstance;
+	}
+
+	public void setMaxRetriesOnSameServiceInstance(int maxRetriesOnSameServiceInstance) {
+		this.maxRetriesOnSameServiceInstance = maxRetriesOnSameServiceInstance;
+	}
+
+	public int getMaxRetriesOnNextServiceInstance() {
+		return maxRetriesOnNextServiceInstance;
+	}
+
+	public void setMaxRetriesOnNextServiceInstance(int maxRetriesOnNextServiceInstance) {
+		this.maxRetriesOnNextServiceInstance = maxRetriesOnNextServiceInstance;
+	}
+
+	public Set<Integer> getRetryableStatusCodes() {
+		return retryableStatusCodes;
+	}
+
+	public void setRetryableStatusCodes(Set<Integer> retryableStatusCodes) {
+		this.retryableStatusCodes = retryableStatusCodes;
+	}
+
 }

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/RetryLoadBalancerInterceptor.java

@@ -39,13 +39,13 @@ import org.springframework.util.StreamUtils;
  */
 public class RetryLoadBalancerInterceptor implements ClientHttpRequestInterceptor {
 
-	private LoadBalancerClient loadBalancer;
+	private final LoadBalancerClient loadBalancer;
 
-	private LoadBalancerRetryProperties lbProperties;
+	private final LoadBalancerRetryProperties lbProperties;
 
-	private LoadBalancerRequestFactory requestFactory;
+	private final LoadBalancerRequestFactory requestFactory;
 
-	private LoadBalancedRetryFactory lbRetryFactory;
+	private final LoadBalancedRetryFactory lbRetryFactory;
 
 	public RetryLoadBalancerInterceptor(LoadBalancerClient loadBalancer,
 			LoadBalancerRetryProperties lbProperties,
@@ -65,8 +65,8 @@ public class RetryLoadBalancerInterceptor implements ClientHttpRequestIntercepto
 		final String serviceName = originalUri.getHost();
 		Assert.state(serviceName != null,
 				"Request URI does not contain a valid hostname: " + originalUri);
-		final LoadBalancedRetryPolicy retryPolicy = this.lbRetryFactory
-				.createRetryPolicy(serviceName, this.loadBalancer);
+		final LoadBalancedRetryPolicy retryPolicy = lbRetryFactory
+				.createRetryPolicy(serviceName, loadBalancer);
 		RetryTemplate template = createRetryTemplate(serviceName, request, retryPolicy);
 		return template.execute(context -> {
 			ServiceInstance serviceInstance = null;
@@ -75,11 +75,11 @@ public class RetryLoadBalancerInterceptor implements ClientHttpRequestIntercepto
 				serviceInstance = lbContext.getServiceInstance();
 			}
 			if (serviceInstance == null) {
-				serviceInstance = this.loadBalancer.choose(serviceName);
+				serviceInstance = loadBalancer.choose(serviceName);
 			}
-			ClientHttpResponse response = RetryLoadBalancerInterceptor.this.loadBalancer
-					.execute(serviceName, serviceInstance,
-							this.requestFactory.createRequest(request, body, execution));
+			ClientHttpResponse response = loadBalancer.execute(serviceName,
+					serviceInstance,
+					requestFactory.createRequest(request, body, execution));
 			int statusCode = response.getRawStatusCode();
 			if (retryPolicy != null && retryPolicy.retryableStatusCode(statusCode)) {
 				byte[] bodyCopy = StreamUtils.copyToByteArray(response.getBody());
@@ -103,19 +103,17 @@ public class RetryLoadBalancerInterceptor implements ClientHttpRequestIntercepto
 	private RetryTemplate createRetryTemplate(String serviceName, HttpRequest request,
 			LoadBalancedRetryPolicy retryPolicy) {
 		RetryTemplate template = new RetryTemplate();
-		BackOffPolicy backOffPolicy = this.lbRetryFactory
-				.createBackOffPolicy(serviceName);
+		BackOffPolicy backOffPolicy = lbRetryFactory.createBackOffPolicy(serviceName);
 		template.setBackOffPolicy(
 				backOffPolicy == null ? new NoBackOffPolicy() : backOffPolicy);
 		template.setThrowLastExceptionOnExhausted(true);
-		RetryListener[] retryListeners = this.lbRetryFactory
-				.createRetryListeners(serviceName);
+		RetryListener[] retryListeners = lbRetryFactory.createRetryListeners(serviceName);
 		if (retryListeners != null && retryListeners.length != 0) {
 			template.setListeners(retryListeners);
 		}
-		template.setRetryPolicy(!this.lbProperties.isEnabled() || retryPolicy == null
+		template.setRetryPolicy(!lbProperties.isEnabled() || retryPolicy == null
 				? new NeverRetryPolicy() : new InterceptorRetryPolicy(request,
-						retryPolicy, this.loadBalancer, serviceName));
+						retryPolicy, loadBalancer, serviceName));
 		return template;
 	}
 

spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/AbstractLoadBalancerAutoConfigurationTests.java

@@ -16,7 +16,6 @@
 
 package org.springframework.cloud.client.loadbalancer;
 
-import java.io.IOException;
 import java.net.URI;
 import java.util.Collection;
 import java.util.Map;
@@ -156,7 +155,7 @@ public abstract class AbstractLoadBalancerAutoConfigurationTests {
 
 		@Override
 		public <T> T execute(String serviceId, ServiceInstance serviceInstance,
-				LoadBalancerRequest<T> request) throws IOException {
+				LoadBalancerRequest<T> request) {
 			try {
 				return request.apply(choose(serviceId));
 			}

spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/InterceptorRetryPolicyTest.java

@@ -20,14 +20,14 @@ import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
-import org.mockito.runners.MockitoJUnitRunner;
+import org.mockito.junit.MockitoJUnitRunner;
 
 import org.springframework.cloud.client.ServiceInstance;
 import org.springframework.http.HttpRequest;
 import org.springframework.retry.RetryContext;
 
 import static org.assertj.core.api.BDDAssertions.then;
-import static org.mockito.Matchers.eq;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
@@ -49,90 +49,89 @@ public class InterceptorRetryPolicyTest {
 
 	@Before
 	public void setup() {
-		this.request = mock(HttpRequest.class);
-		this.policy = mock(LoadBalancedRetryPolicy.class);
-		this.serviceInstanceChooser = mock(ServiceInstanceChooser.class);
-		this.serviceName = "foo";
+		request = mock(HttpRequest.class);
+		policy = mock(LoadBalancedRetryPolicy.class);
+		serviceInstanceChooser = mock(ServiceInstanceChooser.class);
+		serviceName = "foo";
 	}
 
 	@After
 	public void teardown() {
-		this.request = null;
-		this.policy = null;
-		this.serviceInstanceChooser = null;
-		this.serviceName = null;
+		request = null;
+		policy = null;
+		serviceInstanceChooser = null;
+		serviceName = null;
 	}
 
 	@Test
-	public void canRetryBeforeExecution() throws Exception {
+	public void canRetryBeforeExecution() {
 		InterceptorRetryPolicy interceptorRetryPolicy = new InterceptorRetryPolicy(
-				this.request, this.policy, this.serviceInstanceChooser, this.serviceName);
+				request, policy, serviceInstanceChooser, serviceName);
 		LoadBalancedRetryContext context = mock(LoadBalancedRetryContext.class);
 		when(context.getRetryCount()).thenReturn(0);
 		ServiceInstance serviceInstance = mock(ServiceInstance.class);
-		when(this.serviceInstanceChooser.choose(eq(this.serviceName)))
-				.thenReturn(serviceInstance);
+		when(serviceInstanceChooser.choose(eq(serviceName))).thenReturn(serviceInstance);
 		then(interceptorRetryPolicy.canRetry(context)).isTrue();
 		verify(context, times(1)).setServiceInstance(eq(serviceInstance));
 
 	}
 
 	@Test
-	public void canRetryNextServer() throws Exception {
+	public void canRetryNextServer() {
 		InterceptorRetryPolicy interceptorRetryPolicy = new InterceptorRetryPolicy(
-				this.request, this.policy, this.serviceInstanceChooser, this.serviceName);
+				request, policy, serviceInstanceChooser, serviceName);
 		LoadBalancedRetryContext context = mock(LoadBalancedRetryContext.class);
 		when(context.getRetryCount()).thenReturn(1);
-		when(this.policy.canRetryNextServer(eq(context))).thenReturn(true);
+		when(policy.canRetryNextServer(eq(context))).thenReturn(true);
 		then(interceptorRetryPolicy.canRetry(context)).isTrue();
 	}
 
 	@Test
-	public void cannotRetry() throws Exception {
+	public void cannotRetry() {
 		InterceptorRetryPolicy interceptorRetryPolicy = new InterceptorRetryPolicy(
-				this.request, this.policy, this.serviceInstanceChooser, this.serviceName);
+				request, policy, serviceInstanceChooser, serviceName);
 		LoadBalancedRetryContext context = mock(LoadBalancedRetryContext.class);
 		when(context.getRetryCount()).thenReturn(1);
 		then(interceptorRetryPolicy.canRetry(context)).isFalse();
 	}
 
 	@Test
-	public void open() throws Exception {
+	public void open() {
 		InterceptorRetryPolicy interceptorRetryPolicy = new InterceptorRetryPolicy(
-				this.request, this.policy, this.serviceInstanceChooser, this.serviceName);
+				request, policy, serviceInstanceChooser, serviceName);
 		RetryContext context = interceptorRetryPolicy.open(null);
 		then(context).isInstanceOf(LoadBalancedRetryContext.class);
 	}
 
 	@Test
-	public void close() throws Exception {
+	public void close() {
 		InterceptorRetryPolicy interceptorRetryPolicy = new InterceptorRetryPolicy(
-				this.request, this.policy, this.serviceInstanceChooser, this.serviceName);
+				request, policy, serviceInstanceChooser, serviceName);
 		LoadBalancedRetryContext context = mock(LoadBalancedRetryContext.class);
 		interceptorRetryPolicy.close(context);
-		verify(this.policy, times(1)).close(eq(context));
+		verify(policy, times(1)).close(eq(context));
 	}
 
 	@Test
-	public void registerThrowable() throws Exception {
+	public void registerThrowable() {
 		InterceptorRetryPolicy interceptorRetryPolicy = new InterceptorRetryPolicy(
-				this.request, this.policy, this.serviceInstanceChooser, this.serviceName);
+				request, policy, serviceInstanceChooser, serviceName);
 		LoadBalancedRetryContext context = mock(LoadBalancedRetryContext.class);
 		Throwable thrown = new Exception();
 		interceptorRetryPolicy.registerThrowable(context, thrown);
 		verify(context, times(1)).registerThrowable(eq(thrown));
-		verify(this.policy, times(1)).registerThrowable(eq(context), eq(thrown));
+		verify(policy, times(1)).registerThrowable(eq(context), eq(thrown));
 	}
 
 	@Test
-	public void equals() throws Exception {
+	public void equals() {
 		InterceptorRetryPolicy interceptorRetryPolicy = new InterceptorRetryPolicy(
-				this.request, this.policy, this.serviceInstanceChooser, this.serviceName);
+				request, policy, serviceInstanceChooser, serviceName);
 		then(interceptorRetryPolicy.equals(null)).isFalse();
 		then(interceptorRetryPolicy.equals(new Object())).isFalse();
 		then(interceptorRetryPolicy.equals(interceptorRetryPolicy)).isTrue();
-		then(interceptorRetryPolicy.equals(new InterceptorRetryPolicy(this.request,
-				this.policy, this.serviceInstanceChooser, this.serviceName))).isTrue();
+		then(interceptorRetryPolicy.equals(new InterceptorRetryPolicy(request, policy,
+				serviceInstanceChooser, serviceName))).isTrue();
 	}
 
 }

spring-cloud-loadbalancer/pom.xml

@@ -77,6 +77,11 @@
 			<version>${evictor.version}</version>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.retry</groupId>
+			<artifactId>spring-retry</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-test</artifactId>

spring-cloud-loadbalancer/src/main/java/org/springframework/cloud/loadbalancer/blocking/retry/BlockingLoadBalancedRetryFactory.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2012-2020 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.loadbalancer.blocking.retry;
+
+import org.springframework.cloud.client.loadbalancer.LoadBalancedRetryFactory;
+import org.springframework.cloud.client.loadbalancer.LoadBalancedRetryPolicy;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerRetryProperties;
+import org.springframework.cloud.client.loadbalancer.ServiceInstanceChooser;
+import org.springframework.cloud.loadbalancer.blocking.client.BlockingLoadBalancerClient;
+
+/**
+ * An implementation of {@link LoadBalancedRetryFactory} for
+ * {@link BlockingLoadBalancerClient}.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @since 2.2.6
+ */
+public class BlockingLoadBalancedRetryFactory implements LoadBalancedRetryFactory {
+
+	private final LoadBalancerRetryProperties retryProperties;
+
+	public BlockingLoadBalancedRetryFactory(LoadBalancerRetryProperties retryProperties) {
+		this.retryProperties = retryProperties;
+	}
+
+	@Override
+	public LoadBalancedRetryPolicy createRetryPolicy(String serviceId,
+			ServiceInstanceChooser serviceInstanceChooser) {
+		return new BlockingLoadBalancedRetryPolicy(serviceId, serviceInstanceChooser,
+				retryProperties);
+	}
+
+}

spring-cloud-loadbalancer/src/main/java/org/springframework/cloud/loadbalancer/blocking/retry/BlockingLoadBalancedRetryPolicy.java

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2012-2020 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.loadbalancer.blocking.retry;
+
+import org.springframework.cloud.client.loadbalancer.LoadBalancedRetryContext;
+import org.springframework.cloud.client.loadbalancer.LoadBalancedRetryPolicy;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerRetryProperties;
+import org.springframework.cloud.client.loadbalancer.ServiceInstanceChooser;
+import org.springframework.cloud.loadbalancer.blocking.client.BlockingLoadBalancerClient;
+import org.springframework.http.HttpMethod;
+
+/**
+ * A {@link LoadBalancedRetryPolicy} implementation for
+ * {@link BlockingLoadBalancerClient}. Based on <code>RibbonLoadBalancedRetryPolicy</code>
+ * to achieve feature-parity.
+ *
+ * @author Olga Maciaszek-Sharma
+ * @since 2.2.6
+ */
+public class BlockingLoadBalancedRetryPolicy implements LoadBalancedRetryPolicy {
+
+	private final LoadBalancerRetryProperties retryProperties;
+
+	private final ServiceInstanceChooser serviceInstanceChooser;
+
+	private final String serviceId;
+
+	private int sameServerCount = 0;
+
+	private int nextServerCount = 0;
+
+	public BlockingLoadBalancedRetryPolicy(String serviceId,
+			ServiceInstanceChooser serviceInstanceChooser,
+			LoadBalancerRetryProperties retryProperties) {
+		this.serviceId = serviceId;
+		this.serviceInstanceChooser = serviceInstanceChooser;
+		this.retryProperties = retryProperties;
+	}
+
+	public boolean canRetry(LoadBalancedRetryContext context) {
+		HttpMethod method = context.getRequest().getMethod();
+		return HttpMethod.GET.equals(method) || retryProperties.isRetryOnAllOperations();
+	}
+
+	@Override
+	public boolean canRetrySameServer(LoadBalancedRetryContext context) {
+		return sameServerCount < retryProperties.getMaxRetriesOnSameServiceInstance()
+				&& canRetry(context);
+	}
+
+	@Override
+	public boolean canRetryNextServer(LoadBalancedRetryContext context) {
+		// After the failure, we increment first and then check, hence the equality check
+		return nextServerCount <= retryProperties.getMaxRetriesOnNextServiceInstance()
+				&& canRetry(context);
+	}
+
+	@Override
+	public void close(LoadBalancedRetryContext context) {
+
+	}
+
+	@Override
+	public void registerThrowable(LoadBalancedRetryContext context, Throwable throwable) {
+		if (!canRetrySameServer(context) && canRetry(context)) {
+			// Reset same server since we are moving to a new ServiceInstance
+			sameServerCount = 0;
+			nextServerCount++;
+			if (!canRetryNextServer(context)) {
+				context.setExhaustedOnly();
+			}
+			else {
+				context.setServiceInstance(serviceInstanceChooser.choose(serviceId));
+			}
+		}
+		else {
+			sameServerCount++;
+		}
+	}
+
+	@Override
+	public boolean retryableStatusCode(int statusCode) {
+		return retryProperties.getRetryableStatusCodes().contains(statusCode);
+	}
+
+}

spring-cloud-loadbalancer/src/main/java/org/springframework/cloud/loadbalancer/config/BlockingLoadBalancerClientAutoConfiguration.java

@@ -26,15 +26,21 @@ import org.springframework.boot.autoconfigure.AutoConfigureBefore;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.cloud.client.loadbalancer.AsyncLoadBalancerAutoConfiguration;
+import org.springframework.cloud.client.loadbalancer.LoadBalancedRetryFactory;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerRetryProperties;
 import org.springframework.cloud.client.loadbalancer.reactive.OnNoRibbonDefaultCondition;
 import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClients;
 import org.springframework.cloud.loadbalancer.blocking.client.BlockingLoadBalancerClient;
+import org.springframework.cloud.loadbalancer.blocking.retry.BlockingLoadBalancedRetryFactory;
 import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Primary;
+import org.springframework.core.annotation.Order;
+import org.springframework.retry.support.RetryTemplate;
 import org.springframework.web.client.RestTemplate;
 
 /**
@@ -73,6 +79,22 @@ public class BlockingLoadBalancerClientAutoConfiguration {
 			return new BlockingLoadBalancerClient(loadBalancerClientFactory);
 		}
 
+		@Configuration
+		@ConditionalOnClass(RetryTemplate.class)
+		@EnableConfigurationProperties(LoadBalancerRetryProperties.class)
+		protected static class BlockingLoadBalancerRetryConfig {
+
+			@Bean
+			// Allow users to override the factory while avoiding loading
+			// RibbonLoadBalancedRetryFactory.
+			@Order(1000)
+			LoadBalancedRetryFactory loadBalancedRetryFactory(
+					LoadBalancerRetryProperties retryProperties) {
+				return new BlockingLoadBalancedRetryFactory(retryProperties);
+			}
+
+		}
+
 	}
 
 	static class BlockingLoadBalancerClientRibbonWarnLogger {

spring-cloud-loadbalancer/src/test/java/org/springframework/cloud/loadbalancer/blocking/retry/BlockingLoadBalancedRetryPolicyTests.java

@@ -0,0 +1,127 @@
+/*
+ * 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.loadbalancer.blocking.retry;
+
+import java.util.Arrays;
+import java.util.HashSet;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.cloud.client.loadbalancer.LoadBalancedRetryContext;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerRetryProperties;
+import org.springframework.cloud.loadbalancer.blocking.client.BlockingLoadBalancerClient;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpRequest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+/**
+ * Tests for {@link BlockingLoadBalancedRetryPolicy}.
+ *
+ * @author Olga Maciaszek-Sharma
+ */
+class BlockingLoadBalancedRetryPolicyTests {
+
+	private final BlockingLoadBalancerClient loadBalancerClient = mock(
+			BlockingLoadBalancerClient.class);
+
+	private final HttpRequest httpRequest = mock(HttpRequest.class);
+
+	private final LoadBalancedRetryContext context = mock(LoadBalancedRetryContext.class);
+
+	private final LoadBalancerRetryProperties retryProperties = new LoadBalancerRetryProperties();
+
+	private final UnsupportedOperationException exception = new UnsupportedOperationException();
+
+	@BeforeEach
+	void setUp() {
+		when(httpRequest.getMethod()).thenReturn(HttpMethod.GET);
+		when(context.getRequest()).thenReturn(httpRequest);
+	}
+
+	@Test
+	void shouldExecuteIndicatedNumberOfSameAndNextInstanceRetriesAndCloseRetryContext() {
+		retryProperties.setMaxRetriesOnSameServiceInstance(1);
+		BlockingLoadBalancedRetryPolicy retryPolicy = getRetryPolicy(retryProperties);
+
+		assertThat(retryPolicy.canRetrySameServer(context)).isTrue();
+		assertThat(retryPolicy.canRetryNextServer(context)).isTrue();
+
+		retryPolicy.registerThrowable(context, exception);
+		assertThat(retryPolicy.canRetrySameServer(context)).isFalse();
+		assertThat(retryPolicy.canRetryNextServer(context)).isTrue();
+
+		retryPolicy.registerThrowable(context, exception);
+		assertThat(retryPolicy.canRetrySameServer(context)).isTrue();
+		assertThat(retryPolicy.canRetryNextServer(context)).isTrue();
+
+		retryPolicy.registerThrowable(context, exception);
+		assertThat(retryPolicy.canRetrySameServer(context)).isFalse();
+		assertThat(retryPolicy.canRetryNextServer(context)).isTrue();
+
+		retryPolicy.registerThrowable(context, exception);
+		verify(context).setExhaustedOnly();
+		verify(context).setServiceInstance(any());
+		assertThat(retryPolicy.canRetrySameServer(context)).isTrue();
+		assertThat(retryPolicy.canRetryNextServer(context)).isFalse();
+	}
+
+	@Test
+	void shouldNotRetryWhenMethodNotGet() {
+		when(httpRequest.getMethod()).thenReturn(HttpMethod.POST);
+		when(context.getRequest()).thenReturn(httpRequest);
+		BlockingLoadBalancedRetryPolicy retryPolicy = getRetryPolicy(retryProperties);
+
+		boolean canRetry = retryPolicy.canRetry(context);
+
+		assertThat(canRetry).isFalse();
+	}
+
+	@Test
+	void shouldRetryOnPostWhenEnabled() {
+		when(httpRequest.getMethod()).thenReturn(HttpMethod.POST);
+		when(context.getRequest()).thenReturn(httpRequest);
+		retryProperties.setRetryOnAllOperations(true);
+		BlockingLoadBalancedRetryPolicy retryPolicy = getRetryPolicy(retryProperties);
+
+		boolean canRetry = retryPolicy.canRetry(context);
+
+		assertThat(canRetry).isTrue();
+	}
+
+	@Test
+	void shouldResolveRetryableStatusCode() {
+		retryProperties.setRetryableStatusCodes(new HashSet<>(Arrays.asList(404, 502)));
+		BlockingLoadBalancedRetryPolicy retryPolicy = getRetryPolicy(retryProperties);
+
+		boolean retryableStatusCode = retryPolicy.retryableStatusCode(404);
+
+		assertThat(retryableStatusCode).isTrue();
+	}
+
+	private BlockingLoadBalancedRetryPolicy getRetryPolicy(
+			LoadBalancerRetryProperties retryProperties) {
+		return new BlockingLoadBalancedRetryPolicy("test", loadBalancerClient,
+				retryProperties);
+	}
+
+}

spring-cloud-loadbalancer/src/test/java/org/springframework/cloud/loadbalancer/config/BlockingLoadBalancerClientAutoConfigurationTests.java

@@ -16,11 +16,12 @@
 
 package org.springframework.cloud.loadbalancer.config;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.test.context.FilteredClassLoader;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.cloud.client.loadbalancer.LoadBalancedRetryFactory;
 import org.springframework.cloud.loadbalancer.blocking.client.BlockingLoadBalancerClient;
 import org.springframework.cloud.loadbalancer.config.BlockingLoadBalancerClientAutoConfiguration.BlockingLoadBalancerClientRibbonWarnLogger;
 import org.springframework.web.client.RestTemplate;
@@ -32,7 +33,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * @author Olga Maciaszek-Sharma
  * @author Tim Ysewyn
  */
-public class BlockingLoadBalancerClientAutoConfigurationTests {
+class BlockingLoadBalancerClientAutoConfigurationTests {
 
 	private ApplicationContextRunner applicationContextRunner = new ApplicationContextRunner()
 			.withPropertyValues("spring.cloud.loadbalancer.ribbon.enabled=false")
@@ -40,16 +41,17 @@ public class BlockingLoadBalancerClientAutoConfigurationTests {
 					BlockingLoadBalancerClientAutoConfiguration.class));
 
 	@Test
-	public void beansCreatedNormally() {
+	void beansCreatedNormally() {
 		applicationContextRunner.run(ctxt -> {
 			assertThat(ctxt).hasSingleBean(BlockingLoadBalancerClient.class);
+			assertThat(ctxt).hasSingleBean(LoadBalancedRetryFactory.class);
 			assertThat(ctxt)
 					.doesNotHaveBean(BlockingLoadBalancerClientRibbonWarnLogger.class);
 		});
 	}
 
 	@Test
-	public void worksWithoutSpringWeb() {
+	void worksWithoutSpringWeb() {
 		applicationContextRunner
 				.withClassLoader(new FilteredClassLoader(RestTemplate.class))
 				.run(context -> {