Merge pull request spring-projects#216 from ryanjbaxter/retry-on-status-codes

Retry requests on specified status codes.  Fixes spring-projects#215.

Author: ryanjbaxter

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

@@ -103,7 +103,7 @@ public void customize(RestTemplate restTemplate) {
 
 	@Configuration
 	@ConditionalOnClass(RetryTemplate.class)
-	static class RetryAutoConfiguration {
+	public static class RetryAutoConfiguration {
 		@Bean
 		public RetryTemplate retryTemplate() {
 			RetryTemplate template =  new RetryTemplate();
@@ -116,13 +116,18 @@ public RetryTemplate retryTemplate() {
 		public LoadBalancedRetryPolicyFactory loadBalancedRetryPolicyFactory() {
 			return new LoadBalancedRetryPolicyFactory.NeverRetryFactory();
 		}
+	}
 
+	@Configuration
+	@ConditionalOnClass(RetryTemplate.class)
+	public static class RetryInterceptorAutoConfiguration {
 		@Bean
+		@ConditionalOnMissingBean
 		public RetryLoadBalancerInterceptor ribbonInterceptor(
 				LoadBalancerClient loadBalancerClient, LoadBalancerRetryProperties properties,
 				LoadBalancedRetryPolicyFactory lbRetryPolicyFactory,
-				LoadBalancerRequestFactory requestFactory) {
-			return new RetryLoadBalancerInterceptor(loadBalancerClient, retryTemplate(), properties,
+				LoadBalancerRequestFactory requestFactory, RetryTemplate retryTemplate) {
+			return new RetryLoadBalancerInterceptor(loadBalancerClient, retryTemplate, properties,
 					lbRetryPolicyFactory, requestFactory);
 		}
 

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

@@ -68,7 +68,7 @@ public ClientHttpResponse intercept(final HttpRequest request, final byte[] body
 		final URI originalUri = request.getURI();
 		final String serviceName = originalUri.getHost();
 		Assert.state(serviceName != null, "Request URI does not contain a valid hostname: " + originalUri);
-		LoadBalancedRetryPolicy retryPolicy = lbRetryPolicyFactory.create(serviceName,
+		final LoadBalancedRetryPolicy retryPolicy = lbRetryPolicyFactory.create(serviceName,
 				loadBalancer);
 		retryTemplate.setRetryPolicy(
 				!lbProperties.isEnabled() || retryPolicy == null ? new NeverRetryPolicy()
@@ -87,9 +87,13 @@ public ClientHttpResponse doWithRetry(RetryContext context)
 						if (serviceInstance == null) {
 							serviceInstance = loadBalancer.choose(serviceName);
 						}
-						return RetryLoadBalancerInterceptor.this.loadBalancer.execute(
+						ClientHttpResponse response = RetryLoadBalancerInterceptor.this.loadBalancer.execute(
 								serviceName, serviceInstance,
 								requestFactory.createRequest(request, body, execution));
+						if(retryPolicy != null && retryPolicy.retryableStatusCode(response.getRawStatusCode())) {
+							throw new RetryableStatusCodeException(serviceName, response.getRawStatusCode());
+						}
+						return response;
 					}
 				});
 	}

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

@@ -0,0 +1,16 @@
+package org.springframework.cloud.client.loadbalancer;
+
+import java.io.IOException;
+
+/**
+ * Exception to be thrown when the status code is deemed to be retryable.
+ * @author Ryan Baxter
+ */
+public class RetryableStatusCodeException extends IOException {
+
+	private static final String MESSAGE = "Service %s returned a status code of %d";
+
+	public RetryableStatusCodeException(String serviceId, int statusCode) {
+		super(String.format(MESSAGE, serviceId, statusCode));
+	}
+}

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

@@ -132,6 +132,33 @@ public void interceptSuccess() throws Throwable {
         verify(lbRequestFactory).createRequest(request, body, execution);
     }
 
+    @Test
+    public void interceptRetryOnStatusCode() throws Throwable {
+        HttpRequest request = mock(HttpRequest.class);
+        when(request.getURI()).thenReturn(new URI("http://foo"));
+        ClientHttpResponse clientHttpResponseNotFound = new MockClientHttpResponse(new byte[]{}, HttpStatus.NOT_FOUND);
+        ClientHttpResponse clientHttpResponseOk = new MockClientHttpResponse(new byte[]{}, HttpStatus.OK);
+        LoadBalancedRetryPolicy policy = mock(LoadBalancedRetryPolicy.class);
+        when(policy.retryableStatusCode(eq(HttpStatus.NOT_FOUND.value()))).thenReturn(true);
+        when(policy.canRetryNextServer(any(LoadBalancedRetryContext.class))).thenReturn(true);
+        InterceptorRetryPolicy interceptorRetryPolicy = new InterceptorRetryPolicy(request, policy, client,"foo");
+        LoadBalancedRetryPolicyFactory lbRetryPolicyFactory = mock(LoadBalancedRetryPolicyFactory.class);
+        when(lbRetryPolicyFactory.create(eq("foo"), any(ServiceInstanceChooser.class))).thenReturn(policy);
+        ServiceInstance serviceInstance = mock(ServiceInstance.class);
+        when(client.choose(eq("foo"))).thenReturn(serviceInstance);
+        when(client.execute(eq("foo"), eq(serviceInstance), any(LoadBalancerRequest.class))).
+                thenReturn(clientHttpResponseNotFound).thenReturn(clientHttpResponseOk);
+        lbProperties.setEnabled(true);
+        RetryLoadBalancerInterceptor interceptor = new RetryLoadBalancerInterceptor(client, retryTemplate, lbProperties, lbRetryPolicyFactory, lbRequestFactory);
+        byte[] body = new byte[]{};
+        ClientHttpRequestExecution execution = mock(ClientHttpRequestExecution.class);
+        ClientHttpResponse rsp = interceptor.intercept(request, body, execution);
+        verify(client, times(2)).execute(eq("foo"), eq(serviceInstance), any(LoadBalancerRequest.class));
+        assertThat(rsp, is(clientHttpResponseOk));
+        verify(retryTemplate, times(1)).setRetryPolicy(eq(interceptorRetryPolicy));
+        verify(lbRequestFactory, times(2)).createRequest(request, body, execution);
+    }
+
     @Test
     public void interceptRetry() throws Throwable {
         HttpRequest request = mock(HttpRequest.class);