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27 lines
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<title>20. Retrying Failed Requests</title><link rel="stylesheet" type="text/css" href="css/manual-multipage.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><link rel="home" href="multi_spring-cloud.html" title="Spring Cloud"><link rel="up" href="multi__spring_cloud_netflix.html" title="Part III. Spring Cloud Netflix"><link rel="prev" href="multi__polyglot_support_with_sidecar.html" title="19. Polyglot support with Sidecar"><link rel="next" href="multi__http_clients.html" title="21. HTTP Clients"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">20. Retrying Failed Requests</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="multi__polyglot_support_with_sidecar.html">Prev</a> </td><th width="60%" align="center">Part III. Spring Cloud Netflix</th><td width="20%" align="right"> <a accesskey="n" href="multi__http_clients.html">Next</a></td></tr></table><hr></div><div class="chapter"><div class="titlepage"><div><div><h2 class="title"><a name="retrying-failed-requests" href="#retrying-failed-requests"></a>20. Retrying Failed Requests</h2></div></div></div><p>Spring Cloud Netflix offers a variety of ways to make HTTP requests.
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You can use a load balanced <code class="literal">RestTemplate</code>, Ribbon, or Feign.
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No matter how you choose to create your HTTP requests, there is always a chance that a request may fail.
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When a request fails, you may want to have the request be retried automatically.
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To do so when using Sping Cloud Netflix, you need to include <a class="link" href="https://github.com/spring-projects/spring-retry" target="_top">Spring Retry</a> on your application’s classpath.
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When Spring Retry is present, load-balanced <code class="literal">RestTemplates</code>, Feign, and Zuul automatically retry any failed requests (assuming your configuration allows doing so).</p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_backoff_policies" href="#_backoff_policies"></a>20.1 BackOff Policies</h2></div></div></div><p>By default, no backoff policy is used when retrying requests.
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If you would like to configure a backoff policy, you need to create a bean of type <code class="literal">LoadBalancedRetryFactory</code> and override the <code class="literal">createBackOffPolicy</code> method for a given service, as shown in the following example:</p><pre class="programlisting"><em><span class="hl-annotation" style="color: gray">@Configuration</span></em>
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">class</span> MyConfiguration {
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<em><span class="hl-annotation" style="color: gray">@Bean</span></em>
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LoadBalancedRetryFactory retryFactory() {
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">new</span> LoadBalancedRetryFactory() {
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<em><span class="hl-annotation" style="color: gray">@Override</span></em>
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> BackOffPolicy createBackOffPolicy(String service) {
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">return</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">new</span> ExponentialBackOffPolicy();
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}
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};
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}
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}</pre></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_configuration" href="#_configuration"></a>20.2 Configuration</h2></div></div></div><p>When you use Ribbon with Spring Retry, you can control the retry functionality by configuring certain Ribbon properties.
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To do so, set the <code class="literal">client.ribbon.MaxAutoRetries</code>, <code class="literal">client.ribbon.MaxAutoRetriesNextServer</code>, and <code class="literal">client.ribbon.OkToRetryOnAllOperations</code> properties.
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See the <a class="link" href="https://github.com/Netflix/ribbon/wiki/Getting-Started#the-properties-file-sample-clientproperties" target="_top">Ribbon documentation</a> for a description of what these properties do.</p><div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Warning"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Warning]" src="images/warning.png"></td><th align="left">Warning</th></tr><tr><td align="left" valign="top"><p>Enabling <code class="literal">client.ribbon.OkToRetryOnAllOperations</code> includes retrying POST requests, which can have an impact
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on the server’s resources, due to the buffering of the request body.</p></td></tr></table></div><p>In addition, you may want to retry requests when certain status codes are returned in the response.
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You can list the response codes you would like the Ribbon client to retry by setting the <code class="literal">clientName.ribbon.retryableStatusCodes</code> property, as shown in the following example:</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">clientName</span>:
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> ribbon</span>:
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<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> retryableStatusCodes</span>: <span class="hl-number">404</span>,<span class="hl-number">502</span></pre><p>You can also create a bean of type <code class="literal">LoadBalancedRetryPolicy</code> and implement the <code class="literal">retryableStatusCode</code> method to retry a request given the status code.</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_zuul" href="#_zuul"></a>20.2.1 Zuul</h3></div></div></div><p>You can turn off Zuul’s retry functionality by setting <code class="literal">zuul.retryable</code> to <code class="literal">false</code>.
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You can also disable retry functionality on a route-by-route basis by setting <code class="literal">zuul.routes.routename.retryable</code> to <code class="literal">false</code>.</p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="multi__polyglot_support_with_sidecar.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="multi__spring_cloud_netflix.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="multi__http_clients.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">19. Polyglot support with Sidecar </td><td width="20%" align="center"><a accesskey="h" href="multi_spring-cloud.html">Home</a></td><td width="40%" align="right" valign="top"> 21. HTTP Clients</td></tr></table></div></body></html> |