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34 lines
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<title>21. Retrying Failed Requests</title><link rel="stylesheet" type="text/css" href="css/manual-multipage.css"><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><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_netflix-metrics-atlas.html" title="20. Metrics Backend: Atlas"><link rel="next" href="multi__http_clients.html" title="22. 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">21. Retrying Failed Requests</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="multi_netflix-metrics-atlas.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>21. Retrying Failed Requests</h2></div></div></div><p>Spring Cloud Netflix offers a variety of ways to make HTTP requests. You can use a load balanced
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<code class="literal">RestTemplate</code>, Ribbon, or Feign. No matter how you choose to your HTTP requests, there is always
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a chance the request may fail. When a request fails you may want to have the request retried
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automatically. To accomplish this when using Sping Cloud Netflix you need to include
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<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 will automatically
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retry any failed requests (assuming you configuration allows it to).</p><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_backoff_policies" href="#_backoff_policies"></a>21.1 BackOff Policies</h2></div></div></div><p>By default no backoff policy is used when retrying requests. If you would like to configure
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a backoff policy you will need to create a bean of type <code class="literal">LoadBalancedBackOffPolicyFactory</code>
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which will be used to create a <code class="literal">BackOffPolicy</code> for a given service.</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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LoadBalancedBackOffPolicyFactory backOffPolciyFactory() {
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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> LoadBalancedBackOffPolicyFactory() {
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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>21.2 Configuration</h2></div></div></div><p>Anytime Ribbon is used with Spring Retry you can control the retry functionality by configuring
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certain Ribbon properties. The properties you can use are
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<code class="literal">client.ribbon.MaxAutoRetries</code>, <code class="literal">client.ribbon.MaxAutoRetriesNextServer</code>, and
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<code class="literal">client.ribbon.OkToRetryOnAllOperations</code>. See the <a class="link" href="https://github.com/Netflix/ribbon/wiki/Getting-Started#the-properties-file-sample-clientproperties" target="_top">Ribbon documentation</a>
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for a description of what there 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 retring POST requests wich can have a impact
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on the server’s resources due to the buffering of the request’s body.</p></td></tr></table></div><p>In addition you may want to retry requests when certain status codes are returned in the
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response. You can list the response codes you would like the Ribbon client to retry using the
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property <code class="literal">clientName.ribbon.retryableStatusCodes</code>. For 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>
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method to determine whether you want 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>21.2.1 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>. You
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can also disable retry functionality on route by route basis by setting
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<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_netflix-metrics-atlas.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">20. Metrics Backend: Atlas </td><td width="20%" align="center"><a accesskey="h" href="multi_spring-cloud.html">Home</a></td><td width="40%" align="right" valign="top"> 22. HTTP Clients</td></tr></table></div></body></html> |