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@@ -27,7 +27,7 @@
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://example.org
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - AddResponseHeader</span>=X-Response-Foo<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">,</span> Bar</pre><p>
</p><p>This will add <code class="literal">X-Response-Foo:Bar</code> header to the downstream response&#8217;s headers for all matching requests.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_hystrix_gatewayfilter_factory" href="#_hystrix_gatewayfilter_factory"></a>5.4&nbsp;Hystrix GatewayFilter Factory</h2></div></div></div><p><a class="link" href="https://github.com/Netflix/Hystrix" target="_top">Hystrix</a> is a library from Netflix that implements the <a class="link" href="https://martinfowler.com/bliki/CircuitBreaker.html" target="_top">circuit breaker pattern</a>.
</p><p>This will add <code class="literal">X-Response-Foo:Bar</code> header to the downstream response&#8217;s headers for all matching requests.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="hystrix" href="#hystrix"></a>5.4&nbsp;Hystrix GatewayFilter Factory</h2></div></div></div><p><a class="link" href="https://github.com/Netflix/Hystrix" target="_top">Hystrix</a> is a library from Netflix that implements the <a class="link" href="https://martinfowler.com/bliki/CircuitBreaker.html" target="_top">circuit breaker pattern</a>.
The Hystrix GatewayFilter allows you to introduce circuit breakers to your gateway routes, protecting your services from cascading failures and allowing you to provide fallback responses in the event of downstream failures.</p><p>To enable Hystrix GatewayFilters in your project, add a dependency on <code class="literal">spring-cloud-starter-netflix-hystrix</code> from <a class="link" href="http://cloud.spring.io/spring-cloud-netflix/" target="_top">Spring Cloud Netflix</a>.</p><p>The Hystrix GatewayFilter Factory requires a single <code class="literal">name</code> parameter, which is the name of the <code class="literal">HystrixCommand</code>.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
@@ -52,9 +52,59 @@ The Hystrix GatewayFilter allows you to introduce circuit breakers to your gatew
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> name</span>: fallbackcmd
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> fallbackUri</span>: forward:/incaseoffailureusethis
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - RewritePath</span>=/consumingserviceendpoint<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">,</span> /backingserviceendpoint</pre><p>
</p><p>This will forward to the <code class="literal">/incaseoffailureusethis</code> URI when the Hystrix fallback is called. Note that this example also demonstrates (optional) Spring Cloud Netflix Ribbon load-balancing via the <code class="literal">lb</code> prefix on the destination URI.</p><p>Hystrix settings (such as timeouts) can be configured with global defaults or on a route by route basis using application properties as explained on the <a class="link" href="https://github.com/Netflix/Hystrix/wiki/Configuration" target="_top">Hystrix wiki</a>.</p><p>To set a 5 second timeout for the example route above, the following configuration would be used:</p><p><b>application.yml.&nbsp;</b>
</p><p>This will forward to the <code class="literal">/incaseoffailureusethis</code> URI when the Hystrix fallback is called. Note that this example also demonstrates (optional) Spring Cloud Netflix Ribbon load-balancing via the <code class="literal">lb</code> prefix on the destination URI.</p><p>The primary scenario is to use the <code class="literal">fallbackUri</code> to an internal controller or handler within the gateway app.
However, it is also possible to reroute the request to a controller or handler in an external application, like so:</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> routes</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - id</span>: ingredients
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: lb://ingredients
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> predicates</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - Path</span>=//ingredients/**
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - name</span>: Hystrix
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> args</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> name</span>: fetchIngredients
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> fallbackUri</span>: forward:/fallback
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - id</span>: ingredients-fallback
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://localhost:<span class="hl-number">9994</span>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> predicates</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - Path</span>=/fallback</pre><p>
</p><p>In this example, there is no <code class="literal">fallback</code> endpoint or handler in the gateway application, however, there is one in another
app, registered under <code class="literal"><a class="link" href="http://localhost:9994" target="_top">http://localhost:9994</a></code>.</p><p>In case of the request being forwarded to fallback, the Hystrix Gateway filter also provides the <code class="literal">Throwable</code> that has
caused it. It&#8217;s added to the <code class="literal">ServerWebExchange</code> as the
<code class="literal">ServerWebExchangeUtils.HYSTRIX_EXECUTION_EXCEPTION_ATTR</code> attribute that can be used when
handling the fallback within the gateway app.</p><p>For the external controller/ handler scenario, headers can be added with exception details. You can find more information
on it in the <a class="link" href="multi__gatewayfilter_factories.html#fallback-headers" title="5.5&nbsp;FallbackHeaders GatewayFilter Factory">FallbackHeaders GatewayFilter Factory section</a>.</p><p>Hystrix settings (such as timeouts) can be configured with global defaults or on a route by route basis using application properties as explained on the <a class="link" href="https://github.com/Netflix/Hystrix/wiki/Configuration" target="_top">Hystrix wiki</a>.</p><p>To set a 5 second timeout for the example route above, the following configuration would be used:</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">hystrix.command.fallbackcmd.execution.isolation.thread.timeoutInMilliseconds</span>: <span class="hl-number">5000</span></pre><p>
</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_prefixpath_gatewayfilter_factory" href="#_prefixpath_gatewayfilter_factory"></a>5.5&nbsp;PrefixPath GatewayFilter Factory</h2></div></div></div><p>The PrefixPath GatewayFilter Factory takes a single <code class="literal">prefix</code> parameter.</p><p><b>application.yml.&nbsp;</b>
</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="fallback-headers" href="#fallback-headers"></a>5.5&nbsp;FallbackHeaders GatewayFilter Factory</h2></div></div></div><p>The <code class="literal">FallbackHeaders</code> factory allows you to add Hystrix execution exception details in headers of a request forwarded to
a <code class="literal">fallbackUri</code> in an external application, like in the following scenario:</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> routes</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - id</span>: ingredients
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: lb://ingredients
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> predicates</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - Path</span>=//ingredients/**
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - name</span>: Hystrix
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> args</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> name</span>: fetchIngredients
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> fallbackUri</span>: forward:/fallback
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - id</span>: ingredients-fallback
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://localhost:<span class="hl-number">9994</span>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> predicates</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - Path</span>=/fallback
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - name</span>: FallbackHeaders
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> args</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> executionExceptionTypeHeaderName</span>: Test-Header</pre><p>
</p><p>In this example, after an execution exception occurs while running the <code class="literal">HystrixCommand</code>, the request will be forwarde to
the <code class="literal">fallback</code> endpoint or handler in an app running on <code class="literal">localhost:9994</code>. The headers with the exception type, message
and -if available- root cause exception type and message will be added to that request by the <code class="literal">FallbackHeaders</code> filter.</p><p>The names of the headers can be overwritten in the config by setting the values of the arguments listed below, along with
their default values:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">executionExceptionTypeHeaderName</code> (<code class="literal">"Execution-Exception-Type"</code>)</li><li class="listitem"><code class="literal">executionExceptionMessageHeaderName</code> (<code class="literal">"Execution-Exception-Message"</code>)</li><li class="listitem"><code class="literal">rootCauseExceptionTypeHeaderName</code> (<code class="literal">"Root-Cause-Exception-Type"</code>)</li><li class="listitem"><code class="literal">rootCauseExceptionMessageHeaderName</code> (<code class="literal">"Root-Cause-Exception-Message"</code>)</li></ul></div><p>You can find more information on how Hystrix works with Gateway in the <a class="link" href="multi__gatewayfilter_factories.html#hystrix" title="5.4&nbsp;Hystrix GatewayFilter Factory">Hystrix GatewayFilter Factory section</a>.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_prefixpath_gatewayfilter_factory" href="#_prefixpath_gatewayfilter_factory"></a>5.6&nbsp;PrefixPath GatewayFilter Factory</h2></div></div></div><p>The PrefixPath GatewayFilter Factory takes a single <code class="literal">prefix</code> parameter.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -63,7 +113,7 @@ The Hystrix GatewayFilter allows you to introduce circuit breakers to your gatew
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://example.org
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - PrefixPath</span>=/mypath</pre><p>
</p><p>This will prefix <code class="literal">/mypath</code> to the path of all matching requests. So a request to <code class="literal">/hello</code>, would be sent to <code class="literal">/mypath/hello</code>.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_preservehostheader_gatewayfilter_factory" href="#_preservehostheader_gatewayfilter_factory"></a>5.6&nbsp;PreserveHostHeader GatewayFilter Factory</h2></div></div></div><p>The PreserveHostHeader GatewayFilter Factory has not parameters. This filter, sets a request attribute that the routing filter will inspect to determine if the original host header should be sent, rather than the host header determined by the http client.</p><p><b>application.yml.&nbsp;</b>
</p><p>This will prefix <code class="literal">/mypath</code> to the path of all matching requests. So a request to <code class="literal">/hello</code>, would be sent to <code class="literal">/mypath/hello</code>.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_preservehostheader_gatewayfilter_factory" href="#_preservehostheader_gatewayfilter_factory"></a>5.7&nbsp;PreserveHostHeader GatewayFilter Factory</h2></div></div></div><p>The PreserveHostHeader GatewayFilter Factory has not parameters. This filter, sets a request attribute that the routing filter will inspect to determine if the original host header should be sent, rather than the host header determined by the http client.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -72,14 +122,14 @@ The Hystrix GatewayFilter allows you to introduce circuit breakers to your gatew
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://example.org
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
- PreserveHostHeader</pre><p>
</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_requestratelimiter_gatewayfilter_factory" href="#_requestratelimiter_gatewayfilter_factory"></a>5.7&nbsp;RequestRateLimiter GatewayFilter Factory</h2></div></div></div><p>The RequestRateLimiter GatewayFilter Factory is uses a <code class="literal">RateLimiter</code> implementation to determine if the current request is allowed to proceed. If it is not, a status of <code class="literal">HTTP 429 - Too Many Requests</code> (by default) is returned.</p><p>This filter takes an optional <code class="literal">keyResolver</code> parameter and parameters specific to the rate limiter (see below).</p><p><code class="literal">keyResolver</code> is a bean that implements the <code class="literal">KeyResolver</code> interface. In configuration, reference the bean by name using SpEL. <code class="literal">#{@myKeyResolver}</code> is a SpEL expression referencing a bean with the name <code class="literal">myKeyResolver</code>.</p><p><b>KeyResolver.java.&nbsp;</b>
</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_requestratelimiter_gatewayfilter_factory" href="#_requestratelimiter_gatewayfilter_factory"></a>5.8&nbsp;RequestRateLimiter GatewayFilter Factory</h2></div></div></div><p>The RequestRateLimiter GatewayFilter Factory is uses a <code class="literal">RateLimiter</code> implementation to determine if the current request is allowed to proceed. If it is not, a status of <code class="literal">HTTP 429 - Too Many Requests</code> (by default) is returned.</p><p>This filter takes an optional <code class="literal">keyResolver</code> parameter and parameters specific to the rate limiter (see below).</p><p><code class="literal">keyResolver</code> is a bean that implements the <code class="literal">KeyResolver</code> interface. In configuration, reference the bean by name using SpEL. <code class="literal">#{@myKeyResolver}</code> is a SpEL expression referencing a bean with the name <code class="literal">myKeyResolver</code>.</p><p><b>KeyResolver.java.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">public</span> <span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">interface</span> KeyResolver {
Mono&lt;String&gt; resolve(ServerWebExchange exchange);
}</pre><p>
</p><p>The <code class="literal">KeyResolver</code> interface allows pluggable strategies to derive the key for limiting requests. In future milestones, there will be some <code class="literal">KeyResolver</code> implementations.</p><p>The default implementation of <code class="literal">KeyResolver</code> is the <code class="literal">PrincipalNameKeyResolver</code> which retrieves the <code class="literal">Principal</code> from the <code class="literal">ServerWebExchange</code> and calls <code class="literal">Principal.getName()</code>.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>The RequestRateLimiter is not configurable via the "shortcut" notation. The example below is <span class="emphasis"><em>invalid</em></span></p></td></tr></table></div><p><b>application.properties.&nbsp;</b>
</p><pre class="screen"># INVALID SHORTCUT CONFIGURATION
spring.cloud.gateway.routes[0].filters[0]=RequestRateLimiter=2, 2, #{@userkeyresolver}</pre><p>
</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_redis_ratelimiter" href="#_redis_ratelimiter"></a>5.7.1&nbsp;Redis RateLimiter</h3></div></div></div><p>The redis implementation is based off of work done at <a class="link" href="https://stripe.com/blog/rate-limiters" target="_top">Stripe</a>. It requires the use of the <code class="literal">spring-boot-starter-data-redis-reactive</code> Spring Boot starter.</p><p>The algorithm used is the <a class="link" href="https://en.wikipedia.org/wiki/Token_bucket" target="_top">Token Bucket Algorithm</a>.</p><p>The <code class="literal">redis-rate-limiter.replenishRate</code> is how many requests per second do you want a user to be allowed to do, without any dropped requests. This is the rate that the token bucket is filled.</p><p>The <code class="literal">redis-rate-limiter.burstCapacity</code> is the maximum number of requests a user is allowed to do in a single second. This is the number of tokens the token bucket can hold. Setting this value to zero will block all requests.</p><p>A steady rate is accomplished by setting the same value in <code class="literal">replenishRate</code> and <code class="literal">burstCapacity</code>. Temporary bursts can be allowed by setting <code class="literal">burstCapacity</code> higher than <code class="literal">replenishRate</code>. In this case, the rate limiter needs to be allowed some time between bursts (according to <code class="literal">replenishRate</code>), as 2 consecutive bursts will result in dropped requests (<code class="literal">HTTP 429 - Too Many Requests</code>).</p><p><b>application.yml.&nbsp;</b>
</p><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="_redis_ratelimiter" href="#_redis_ratelimiter"></a>5.8.1&nbsp;Redis RateLimiter</h3></div></div></div><p>The redis implementation is based off of work done at <a class="link" href="https://stripe.com/blog/rate-limiters" target="_top">Stripe</a>. It requires the use of the <code class="literal">spring-boot-starter-data-redis-reactive</code> Spring Boot starter.</p><p>The algorithm used is the <a class="link" href="https://en.wikipedia.org/wiki/Token_bucket" target="_top">Token Bucket Algorithm</a>.</p><p>The <code class="literal">redis-rate-limiter.replenishRate</code> is how many requests per second do you want a user to be allowed to do, without any dropped requests. This is the rate that the token bucket is filled.</p><p>The <code class="literal">redis-rate-limiter.burstCapacity</code> is the maximum number of requests a user is allowed to do in a single second. This is the number of tokens the token bucket can hold. Setting this value to zero will block all requests.</p><p>A steady rate is accomplished by setting the same value in <code class="literal">replenishRate</code> and <code class="literal">burstCapacity</code>. Temporary bursts can be allowed by setting <code class="literal">burstCapacity</code> higher than <code class="literal">replenishRate</code>. In this case, the rate limiter needs to be allowed some time between bursts (according to <code class="literal">replenishRate</code>), as 2 consecutive bursts will result in dropped requests (<code class="literal">HTTP 429 - Too Many Requests</code>).</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -108,7 +158,7 @@ KeyResolver userKeyResolver() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> args</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> rate-limiter</span>: <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"#{@myRateLimiter}"</span>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> key-resolver</span>: <span xmlns:d="http://docbook.org/ns/docbook" class="hl-string">"#{@userKeyResolver}"</span></pre><p>
</p></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_redirectto_gatewayfilter_factory" href="#_redirectto_gatewayfilter_factory"></a>5.8&nbsp;RedirectTo GatewayFilter Factory</h2></div></div></div><p>The RedirectTo GatewayFilter Factory takes a <code class="literal">status</code> and a <code class="literal">url</code> parameter. The status should be a 300 series redirect http code, such as 301. The url should be a valid url. This will be the value of the <code class="literal">Location</code> header.</p><p><b>application.yml.&nbsp;</b>
</p></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_redirectto_gatewayfilter_factory" href="#_redirectto_gatewayfilter_factory"></a>5.9&nbsp;RedirectTo GatewayFilter Factory</h2></div></div></div><p>The RedirectTo GatewayFilter Factory takes a <code class="literal">status</code> and a <code class="literal">url</code> parameter. The status should be a 300 series redirect http code, such as 301. The url should be a valid url. This will be the value of the <code class="literal">Location</code> header.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -117,7 +167,7 @@ KeyResolver userKeyResolver() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://example.org
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - RedirectTo</span>=<span class="hl-number">302</span><span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">,</span> http://acme.org</pre><p>
</p><p>This will send a status 302 with a <code class="literal">Location:http://acme.org</code> header to perform a redirect.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_removenonproxyheaders_gatewayfilter_factory" href="#_removenonproxyheaders_gatewayfilter_factory"></a>5.9&nbsp;RemoveNonProxyHeaders GatewayFilter Factory</h2></div></div></div><p>The RemoveNonProxyHeaders GatewayFilter Factory removes headers from forwarded requests. The default list of headers that is removed comes from the <a class="link" href="https://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-7.1.3" target="_top">IETF</a>.</p><div class="itemizedlist"><p class="title"><b>The default removed headers are:</b></p><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">Connection</li><li class="listitem">Keep-Alive</li><li class="listitem">Proxy-Authenticate</li><li class="listitem">Proxy-Authorization</li><li class="listitem">TE</li><li class="listitem">Trailer</li><li class="listitem">Transfer-Encoding</li><li class="listitem">Upgrade</li></ul></div><p>To change this, set the <code class="literal">spring.cloud.gateway.filter.remove-non-proxy-headers.headers</code> property to the list of header names to remove.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_removerequestheader_gatewayfilter_factory" href="#_removerequestheader_gatewayfilter_factory"></a>5.10&nbsp;RemoveRequestHeader GatewayFilter Factory</h2></div></div></div><p>The RemoveRequestHeader GatewayFilter Factory takes a <code class="literal">name</code> parameter. It is the name of the header to be removed.</p><p><b>application.yml.&nbsp;</b>
</p><p>This will send a status 302 with a <code class="literal">Location:http://acme.org</code> header to perform a redirect.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_removenonproxyheaders_gatewayfilter_factory" href="#_removenonproxyheaders_gatewayfilter_factory"></a>5.10&nbsp;RemoveNonProxyHeaders GatewayFilter Factory</h2></div></div></div><p>The RemoveNonProxyHeaders GatewayFilter Factory removes headers from forwarded requests. The default list of headers that is removed comes from the <a class="link" href="https://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-14#section-7.1.3" target="_top">IETF</a>.</p><div class="itemizedlist"><p class="title"><b>The default removed headers are:</b></p><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">Connection</li><li class="listitem">Keep-Alive</li><li class="listitem">Proxy-Authenticate</li><li class="listitem">Proxy-Authorization</li><li class="listitem">TE</li><li class="listitem">Trailer</li><li class="listitem">Transfer-Encoding</li><li class="listitem">Upgrade</li></ul></div><p>To change this, set the <code class="literal">spring.cloud.gateway.filter.remove-non-proxy-headers.headers</code> property to the list of header names to remove.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_removerequestheader_gatewayfilter_factory" href="#_removerequestheader_gatewayfilter_factory"></a>5.11&nbsp;RemoveRequestHeader GatewayFilter Factory</h2></div></div></div><p>The RemoveRequestHeader GatewayFilter Factory takes a <code class="literal">name</code> parameter. It is the name of the header to be removed.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -126,7 +176,7 @@ KeyResolver userKeyResolver() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://example.org
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - RemoveRequestHeader</span>=X-Request-Foo</pre><p>
</p><p>This will remove the <code class="literal">X-Request-Foo</code> header before it is sent downstream.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_removeresponseheader_gatewayfilter_factory" href="#_removeresponseheader_gatewayfilter_factory"></a>5.11&nbsp;RemoveResponseHeader GatewayFilter Factory</h2></div></div></div><p>The RemoveResponseHeader GatewayFilter Factory takes a <code class="literal">name</code> parameter. It is the name of the header to be removed.</p><p><b>application.yml.&nbsp;</b>
</p><p>This will remove the <code class="literal">X-Request-Foo</code> header before it is sent downstream.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_removeresponseheader_gatewayfilter_factory" href="#_removeresponseheader_gatewayfilter_factory"></a>5.12&nbsp;RemoveResponseHeader GatewayFilter Factory</h2></div></div></div><p>The RemoveResponseHeader GatewayFilter Factory takes a <code class="literal">name</code> parameter. It is the name of the header to be removed.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -135,7 +185,7 @@ KeyResolver userKeyResolver() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://example.org
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - RemoveResponseHeader</span>=X-Response-Foo</pre><p>
</p><p>This will remove the <code class="literal">X-Response-Foo</code> header from the response before it is returned to the gateway client.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_rewritepath_gatewayfilter_factory" href="#_rewritepath_gatewayfilter_factory"></a>5.12&nbsp;RewritePath GatewayFilter Factory</h2></div></div></div><p>The RewritePath GatewayFilter Factory takes a path <code class="literal">regexp</code> parameter and a <code class="literal">replacement</code> parameter. This uses Java regular expressions for a flexible way to rewrite the request path.</p><p><b>application.yml.&nbsp;</b>
</p><p>This will remove the <code class="literal">X-Response-Foo</code> header from the response before it is returned to the gateway client.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_rewritepath_gatewayfilter_factory" href="#_rewritepath_gatewayfilter_factory"></a>5.13&nbsp;RewritePath GatewayFilter Factory</h2></div></div></div><p>The RewritePath GatewayFilter Factory takes a path <code class="literal">regexp</code> parameter and a <code class="literal">replacement</code> parameter. This uses Java regular expressions for a flexible way to rewrite the request path.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -146,7 +196,7 @@ KeyResolver userKeyResolver() {
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - Path</span>=/foo/**
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - RewritePath</span>=/foo/(?&lt;segment&gt;.*)<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">,</span> /$\{segment<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">}</span></pre><p>
</p><p>For a request path of <code class="literal">/foo/bar</code>, this will set the path to <code class="literal">/bar</code> before making the downstream request. Notice the <code class="literal">$\</code> which is replaced with <code class="literal">$</code> because of the YAML spec.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_savesession_gatewayfilter_factory" href="#_savesession_gatewayfilter_factory"></a>5.13&nbsp;SaveSession GatewayFilter Factory</h2></div></div></div><p>The SaveSession GatewayFilter Factory forces a <code class="literal">WebSession::save</code> operation <span class="emphasis"><em>before</em></span> forwarding the call downstream. This is of particular use when
</p><p>For a request path of <code class="literal">/foo/bar</code>, this will set the path to <code class="literal">/bar</code> before making the downstream request. Notice the <code class="literal">$\</code> which is replaced with <code class="literal">$</code> because of the YAML spec.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_savesession_gatewayfilter_factory" href="#_savesession_gatewayfilter_factory"></a>5.14&nbsp;SaveSession GatewayFilter Factory</h2></div></div></div><p>The SaveSession GatewayFilter Factory forces a <code class="literal">WebSession::save</code> operation <span class="emphasis"><em>before</em></span> forwarding the call downstream. This is of particular use when
using something like <a class="link" href="http://projects.spring.io/spring-session/" target="_top">Spring Session</a> with a lazy data store and need to ensure the session state has been saved before making the forwarded call.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
@@ -158,7 +208,7 @@ using something like <a class="link" href="http://projects.spring.io/spring-sess
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - Path</span>=/foo/**
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
- SaveSession</pre><p>
</p><p>If you are integrating <a class="link" href="http://projects.spring.io/spring-security/" target="_top">Spring Security</a> with Spring Session, and want to ensure security details have been forwarded to the remote process, this is critical.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_secureheaders_gatewayfilter_factory" href="#_secureheaders_gatewayfilter_factory"></a>5.14&nbsp;SecureHeaders GatewayFilter Factory</h2></div></div></div><p>The SecureHeaders GatewayFilter Factory adds a number of headers to the response at the reccomendation from <a class="link" href="https://blog.appcanary.com/2017/http-security-headers.html" target="_top">this blog post</a>.</p><div class="itemizedlist"><p class="title"><b>The following headers are added (allong with default values):</b></p><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">X-Xss-Protection:1; mode=block</code></li><li class="listitem"><code class="literal">Strict-Transport-Security:max-age=631138519</code></li><li class="listitem"><code class="literal">X-Frame-Options:DENY</code></li><li class="listitem"><code class="literal">X-Content-Type-Options:nosniff</code></li><li class="listitem"><code class="literal">Referrer-Policy:no-referrer</code></li><li class="listitem"><code class="literal">Content-Security-Policy:default-src 'self' https:; font-src 'self' https: data:; img-src 'self' https: data:; object-src 'none'; script-src https:; style-src 'self' https: 'unsafe-inline'</code></li><li class="listitem"><code class="literal">X-Download-Options:noopen</code></li><li class="listitem"><code class="literal">X-Permitted-Cross-Domain-Policies:none</code></li></ul></div><p>To change the default values set the appropriate property in the <code class="literal">spring.cloud.gateway.filter.secure-headers</code> namespace:</p><div class="itemizedlist"><p class="title"><b>Property to change:</b></p><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">xss-protection-header</code></li><li class="listitem"><code class="literal">strict-transport-security</code></li><li class="listitem"><code class="literal">frame-options</code></li><li class="listitem"><code class="literal">content-type-options</code></li><li class="listitem"><code class="literal">referrer-policy</code></li><li class="listitem"><code class="literal">content-security-policy</code></li><li class="listitem"><code class="literal">download-options</code></li><li class="listitem"><code class="literal">permitted-cross-domain-policies</code></li></ul></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_setpath_gatewayfilter_factory" href="#_setpath_gatewayfilter_factory"></a>5.15&nbsp;SetPath GatewayFilter Factory</h2></div></div></div><p>The SetPath GatewayFilter Factory takes a path <code class="literal">template</code> parameter. It offers a simple way to manipulate the request path by allowing templated segments of the path. This uses the uri templates from Spring Framework. Multiple matching segments are allowed.</p><p><b>application.yml.&nbsp;</b>
</p><p>If you are integrating <a class="link" href="http://projects.spring.io/spring-security/" target="_top">Spring Security</a> with Spring Session, and want to ensure security details have been forwarded to the remote process, this is critical.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_secureheaders_gatewayfilter_factory" href="#_secureheaders_gatewayfilter_factory"></a>5.15&nbsp;SecureHeaders GatewayFilter Factory</h2></div></div></div><p>The SecureHeaders GatewayFilter Factory adds a number of headers to the response at the reccomendation from <a class="link" href="https://blog.appcanary.com/2017/http-security-headers.html" target="_top">this blog post</a>.</p><div class="itemizedlist"><p class="title"><b>The following headers are added (allong with default values):</b></p><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">X-Xss-Protection:1; mode=block</code></li><li class="listitem"><code class="literal">Strict-Transport-Security:max-age=631138519</code></li><li class="listitem"><code class="literal">X-Frame-Options:DENY</code></li><li class="listitem"><code class="literal">X-Content-Type-Options:nosniff</code></li><li class="listitem"><code class="literal">Referrer-Policy:no-referrer</code></li><li class="listitem"><code class="literal">Content-Security-Policy:default-src 'self' https:; font-src 'self' https: data:; img-src 'self' https: data:; object-src 'none'; script-src https:; style-src 'self' https: 'unsafe-inline'</code></li><li class="listitem"><code class="literal">X-Download-Options:noopen</code></li><li class="listitem"><code class="literal">X-Permitted-Cross-Domain-Policies:none</code></li></ul></div><p>To change the default values set the appropriate property in the <code class="literal">spring.cloud.gateway.filter.secure-headers</code> namespace:</p><div class="itemizedlist"><p class="title"><b>Property to change:</b></p><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">xss-protection-header</code></li><li class="listitem"><code class="literal">strict-transport-security</code></li><li class="listitem"><code class="literal">frame-options</code></li><li class="listitem"><code class="literal">content-type-options</code></li><li class="listitem"><code class="literal">referrer-policy</code></li><li class="listitem"><code class="literal">content-security-policy</code></li><li class="listitem"><code class="literal">download-options</code></li><li class="listitem"><code class="literal">permitted-cross-domain-policies</code></li></ul></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_setpath_gatewayfilter_factory" href="#_setpath_gatewayfilter_factory"></a>5.16&nbsp;SetPath GatewayFilter Factory</h2></div></div></div><p>The SetPath GatewayFilter Factory takes a path <code class="literal">template</code> parameter. It offers a simple way to manipulate the request path by allowing templated segments of the path. This uses the uri templates from Spring Framework. Multiple matching segments are allowed.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -169,7 +219,7 @@ using something like <a class="link" href="http://projects.spring.io/spring-sess
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - Path</span>=/foo/{segment<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">}</span>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - SetPath</span>=/{segment<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">}</span></pre><p>
</p><p>For a request path of <code class="literal">/foo/bar</code>, this will set the path to <code class="literal">/bar</code> before making the downstream request.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_setresponseheader_gatewayfilter_factory" href="#_setresponseheader_gatewayfilter_factory"></a>5.16&nbsp;SetResponseHeader GatewayFilter Factory</h2></div></div></div><p>The SetResponseHeader GatewayFilter Factory takes <code class="literal">name</code> and <code class="literal">value</code> parameters.</p><p><b>application.yml.&nbsp;</b>
</p><p>For a request path of <code class="literal">/foo/bar</code>, this will set the path to <code class="literal">/bar</code> before making the downstream request.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_setresponseheader_gatewayfilter_factory" href="#_setresponseheader_gatewayfilter_factory"></a>5.17&nbsp;SetResponseHeader GatewayFilter Factory</h2></div></div></div><p>The SetResponseHeader GatewayFilter Factory takes <code class="literal">name</code> and <code class="literal">value</code> parameters.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -178,7 +228,7 @@ using something like <a class="link" href="http://projects.spring.io/spring-sess
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://example.org
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - SetResponseHeader</span>=X-Response-Foo<span xmlns:d="http://docbook.org/ns/docbook" class="hl-keyword">,</span> Bar</pre><p>
</p><p>This GatewayFilter replaces all headers with the given name, rather than adding. So if the downstream server responded with a <code class="literal">X-Response-Foo:1234</code>, this would be replaced with <code class="literal">X-Response-Foo:Bar</code>, which is what the gateway client would receive.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_setstatus_gatewayfilter_factory" href="#_setstatus_gatewayfilter_factory"></a>5.17&nbsp;SetStatus GatewayFilter Factory</h2></div></div></div><p>The SetStatus GatewayFilter Factory takes a single <code class="literal">status</code> parameter. It must be a valid Spring <code class="literal">HttpStatus</code>. It may be the integer value <code class="literal">404</code> or the string representation of the enumeration <code class="literal">NOT_FOUND</code>.</p><p><b>application.yml.&nbsp;</b>
</p><p>This GatewayFilter replaces all headers with the given name, rather than adding. So if the downstream server responded with a <code class="literal">X-Response-Foo:1234</code>, this would be replaced with <code class="literal">X-Response-Foo:Bar</code>, which is what the gateway client would receive.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_setstatus_gatewayfilter_factory" href="#_setstatus_gatewayfilter_factory"></a>5.18&nbsp;SetStatus GatewayFilter Factory</h2></div></div></div><p>The SetStatus GatewayFilter Factory takes a single <code class="literal">status</code> parameter. It must be a valid Spring <code class="literal">HttpStatus</code>. It may be the integer value <code class="literal">404</code> or the string representation of the enumeration <code class="literal">NOT_FOUND</code>.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -191,7 +241,7 @@ using something like <a class="link" href="http://projects.spring.io/spring-sess
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> uri</span>: http://example.org
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - SetStatus</span>=<span class="hl-number">401</span></pre><p>
</p><p>In either case, the HTTP status of the response will be set to 401.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_stripprefix_gatewayfilter_factory" href="#_stripprefix_gatewayfilter_factory"></a>5.18&nbsp;StripPrefix GatewayFilter Factory</h2></div></div></div><p>The StripPrefix GatewayFilter Factory takes one paramter, <code class="literal">parts</code>. The <code class="literal">parts</code> parameter indicated the number of parts in the path to strip from the request before sending it downstream.</p><p><b>application.yml.&nbsp;</b>
</p><p>In either case, the HTTP status of the response will be set to 401.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_stripprefix_gatewayfilter_factory" href="#_stripprefix_gatewayfilter_factory"></a>5.19&nbsp;StripPrefix GatewayFilter Factory</h2></div></div></div><p>The StripPrefix GatewayFilter Factory takes one paramter, <code class="literal">parts</code>. The <code class="literal">parts</code> parameter indicated the number of parts in the path to strip from the request before sending it downstream.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -202,7 +252,7 @@ using something like <a class="link" href="http://projects.spring.io/spring-sess
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - Path</span>=/name/**
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> filters</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> - StripPrefix</span>=<span class="hl-number">2</span></pre><p>
</p><p>When a request is made through the gateway to <code class="literal">/name/bar/foo</code> the request made to <code class="literal">nameservice</code> will look like <code class="literal"><a class="link" href="http://nameservice/foo" target="_top">http://nameservice/foo</a></code>.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_retry_gatewayfilter_factory" href="#_retry_gatewayfilter_factory"></a>5.19&nbsp;Retry GatewayFilter Factory</h2></div></div></div><p>The Retry GatewayFilter Factory takes <code class="literal">retries</code>, <code class="literal">statuses</code>, <code class="literal">methods</code>, and <code class="literal">series</code> as parameters.</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">retries</code>: the number of retries that should be attempted</li><li class="listitem"><code class="literal">statuses</code>: the HTTP status codes that should be retried, represented using <code class="literal">org.springframework.http.HttpStatus</code></li><li class="listitem"><code class="literal">methods</code>: the HTTP methods that should be retried, represented using <code class="literal">org.springframework.http.HttpMethod</code></li><li class="listitem"><code class="literal">series</code>: the series of status codes to be retried, represented using <code class="literal">org.springframework.http.HttpStatus.Series</code></li></ul></div><p><b>application.yml.&nbsp;</b>
</p><p>When a request is made through the gateway to <code class="literal">/name/bar/foo</code> the request made to <code class="literal">nameservice</code> will look like <code class="literal"><a class="link" href="http://nameservice/foo" target="_top">http://nameservice/foo</a></code>.</p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_retry_gatewayfilter_factory" href="#_retry_gatewayfilter_factory"></a>5.20&nbsp;Retry GatewayFilter Factory</h2></div></div></div><p>The Retry GatewayFilter Factory takes <code class="literal">retries</code>, <code class="literal">statuses</code>, <code class="literal">methods</code>, and <code class="literal">series</code> as parameters.</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">retries</code>: the number of retries that should be attempted</li><li class="listitem"><code class="literal">statuses</code>: the HTTP status codes that should be retried, represented using <code class="literal">org.springframework.http.HttpStatus</code></li><li class="listitem"><code class="literal">methods</code>: the HTTP methods that should be retried, represented using <code class="literal">org.springframework.http.HttpMethod</code></li><li class="listitem"><code class="literal">series</code>: the series of status codes to be retried, represented using <code class="literal">org.springframework.http.HttpStatus.Series</code></li></ul></div><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:
@@ -216,7 +266,7 @@ using something like <a class="link" href="http://projects.spring.io/spring-sess
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> args</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> retries</span>: <span class="hl-number">3</span>
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> statuses</span>: BAD_GATEWAY</pre><p>
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>When using the retry filter with a <code class="literal">forward:</code> prefixed URL, the target endpoint should be written carefully so that in case of an error it does not do anything that could result in a response being sent to the client and committed. For example, if the target endpoint is an annotated controller, the target controller method should not return <code class="literal">ResponseEntity</code> with an error status code. Instead it should throw an <code class="literal">Exception</code>, or signal an error, e.g. via a <code class="literal">Mono.error(ex)</code> return value, which the retry filter can be configured to handle by retrying.</p></td></tr></table></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_requestsize_gatewayfilter_factory" href="#_requestsize_gatewayfilter_factory"></a>5.20&nbsp;RequestSize GatewayFilter Factory</h2></div></div></div><p>The RequestSize GatewayFilter Factory can restrict a request from reaching the downstream service , when the request size is greater than the permissible limit. The filter takes <code class="literal">RequestSize</code> as parameter which is the permissible size limit of the request defined in bytes.</p><p><b>application.yml.&nbsp;</b>
</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><table border="0" summary="Note"><tr><td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="images/note.png"></td><th align="left">Note</th></tr><tr><td align="left" valign="top"><p>When using the retry filter with a <code class="literal">forward:</code> prefixed URL, the target endpoint should be written carefully so that in case of an error it does not do anything that could result in a response being sent to the client and committed. For example, if the target endpoint is an annotated controller, the target controller method should not return <code class="literal">ResponseEntity</code> with an error status code. Instead it should throw an <code class="literal">Exception</code>, or signal an error, e.g. via a <code class="literal">Mono.error(ex)</code> return value, which the retry filter can be configured to handle by retrying.</p></td></tr></table></div></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="_requestsize_gatewayfilter_factory" href="#_requestsize_gatewayfilter_factory"></a>5.21&nbsp;RequestSize GatewayFilter Factory</h2></div></div></div><p>The RequestSize GatewayFilter Factory can restrict a request from reaching the downstream service , when the request size is greater than the permissible limit. The filter takes <code class="literal">RequestSize</code> as parameter which is the permissible size limit of the request defined in bytes.</p><p><b>application.yml.&nbsp;</b>
</p><pre class="programlisting"><span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute">spring</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> cloud</span>:
<span xmlns:d="http://docbook.org/ns/docbook" class="hl-attribute"> gateway</span>:

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@@ -371,7 +371,7 @@ If two hops of trusted infrastructure are required before Spring Cloud Gateway i
</formalpara>
<simpara>This will add <literal>X-Response-Foo:Bar</literal> header to the downstream response&#8217;s headers for all matching requests.</simpara>
</section>
<section xml:id="_hystrix_gatewayfilter_factory">
<section xml:id="hystrix">
<title>Hystrix GatewayFilter Factory</title>
<simpara><link xl:href="https://github.com/Netflix/Hystrix">Hystrix</link> is a library from Netflix that implements the <link xl:href="https://martinfowler.com/bliki/CircuitBreaker.html">circuit breaker pattern</link>.
The Hystrix GatewayFilter allows you to introduce circuit breakers to your gateway routes, protecting your services from cascading failures and allowing you to provide fallback responses in the event of downstream failures.</simpara>
@@ -412,6 +412,38 @@ The Hystrix GatewayFilter allows you to introduce circuit breakers to your gatew
</para>
</formalpara>
<simpara>This will forward to the <literal>/incaseoffailureusethis</literal> URI when the Hystrix fallback is called. Note that this example also demonstrates (optional) Spring Cloud Netflix Ribbon load-balancing via the <literal>lb</literal> prefix on the destination URI.</simpara>
<simpara>The primary scenario is to use the <literal>fallbackUri</literal> to an internal controller or handler within the gateway app.
However, it is also possible to reroute the request to a controller or handler in an external application, like so:</simpara>
<formalpara>
<title>application.yml</title>
<para>
<programlisting language="yaml" linenumbering="unnumbered">spring:
cloud:
gateway:
routes:
- id: ingredients
uri: lb://ingredients
predicates:
- Path=//ingredients/**
filters:
- name: Hystrix
args:
name: fetchIngredients
fallbackUri: forward:/fallback
- id: ingredients-fallback
uri: http://localhost:9994
predicates:
- Path=/fallback</programlisting>
</para>
</formalpara>
<simpara>In this example, there is no <literal>fallback</literal> endpoint or handler in the gateway application, however, there is one in another
app, registered under <literal><link xl:href="http://localhost:9994">http://localhost:9994</link></literal>.</simpara>
<simpara>In case of the request being forwarded to fallback, the Hystrix Gateway filter also provides the <literal>Throwable</literal> that has
caused it. It&#8217;s added to the <literal>ServerWebExchange</literal> as the
<literal>ServerWebExchangeUtils.HYSTRIX_EXECUTION_EXCEPTION_ATTR</literal> attribute that can be used when
handling the fallback within the gateway app.</simpara>
<simpara>For the external controller/ handler scenario, headers can be added with exception details. You can find more information
on it in the <link linkend="fallback-headers">FallbackHeaders GatewayFilter Factory section</link>.</simpara>
<simpara>Hystrix settings (such as timeouts) can be configured with global defaults or on a route by route basis using application properties as explained on the <link xl:href="https://github.com/Netflix/Hystrix/wiki/Configuration">Hystrix wiki</link>.</simpara>
<simpara>To set a 5 second timeout for the example route above, the following configuration would be used:</simpara>
<formalpara>
@@ -421,6 +453,57 @@ The Hystrix GatewayFilter allows you to introduce circuit breakers to your gatew
</para>
</formalpara>
</section>
<section xml:id="fallback-headers">
<title>FallbackHeaders GatewayFilter Factory</title>
<simpara>The <literal>FallbackHeaders</literal> factory allows you to add Hystrix execution exception details in headers of a request forwarded to
a <literal>fallbackUri</literal> in an external application, like in the following scenario:</simpara>
<formalpara>
<title>application.yml</title>
<para>
<programlisting language="yaml" linenumbering="unnumbered">spring:
cloud:
gateway:
routes:
- id: ingredients
uri: lb://ingredients
predicates:
- Path=//ingredients/**
filters:
- name: Hystrix
args:
name: fetchIngredients
fallbackUri: forward:/fallback
- id: ingredients-fallback
uri: http://localhost:9994
predicates:
- Path=/fallback
filters:
- name: FallbackHeaders
args:
executionExceptionTypeHeaderName: Test-Header</programlisting>
</para>
</formalpara>
<simpara>In this example, after an execution exception occurs while running the <literal>HystrixCommand</literal>, the request will be forwarde to
the <literal>fallback</literal> endpoint or handler in an app running on <literal>localhost:9994</literal>. The headers with the exception type, message
and -if available- root cause exception type and message will be added to that request by the <literal>FallbackHeaders</literal> filter.</simpara>
<simpara>The names of the headers can be overwritten in the config by setting the values of the arguments listed below, along with
their default values:</simpara>
<itemizedlist>
<listitem>
<simpara><literal>executionExceptionTypeHeaderName</literal> (<literal>"Execution-Exception-Type"</literal>)</simpara>
</listitem>
<listitem>
<simpara><literal>executionExceptionMessageHeaderName</literal> (<literal>"Execution-Exception-Message"</literal>)</simpara>
</listitem>
<listitem>
<simpara><literal>rootCauseExceptionTypeHeaderName</literal> (<literal>"Root-Cause-Exception-Type"</literal>)</simpara>
</listitem>
<listitem>
<simpara><literal>rootCauseExceptionMessageHeaderName</literal> (<literal>"Root-Cause-Exception-Message"</literal>)</simpara>
</listitem>
</itemizedlist>
<simpara>You can find more information on how Hystrix works with Gateway in the <link linkend="hystrix">Hystrix GatewayFilter Factory section</link>.</simpara>
</section>
<section xml:id="_prefixpath_gatewayfilter_factory">
<title>PrefixPath GatewayFilter Factory</title>
<simpara>The PrefixPath GatewayFilter Factory takes a single <literal>prefix</literal> parameter.</simpara>