[[hystrix-eip]]
== Hystrix EIP

*Available as of Camel 2.18*

The Hystrix EIP provides integration with Netflix link:https://github.com/Netflix/Hystrix[Hystrix] to be used as circuit breaker in the Camel routes. Hystrix is a latency and fault tolerance library designed to isolate points of access to remote systems, services and 3rd party libraries, stop cascading failure and enable resilience in complex distributed systems where failure is inevitable.

Maven users will need to add the following dependency to their pom.xml to use this EIP:

[source]
----
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-hystrix</artifactId>
    <version>x.x.x</version><!-- use the same version as your Camel core version -->
</dependency>
----

=== Configuration options

// eip options: START
The Hystrix EIP supports 2 options which are listed below:

[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *hystrixConfiguration* | Configures the Hystrix EIP Use end when configuration is complete, to return back to the Hystrix EIP. |  | HystrixConfiguration Definition
| *hystrixConfigurationRef* | Refers to a Hystrix configuration to use for configuring the Hystrix EIP. |  | String
|===
// eip options: END

=== Samples

Below is an example route showing an Hystrix endpoint that protects against slow operation by falling back to the in-lined fallback route. By default the timeout request is just *1000ms* so the HTTP endpoint has to be fairly quick to succeed.
[source,java]
----
from("direct:start")
    .hystrix()
        .to("http://fooservice.com/slow")
    .onFallback()
        .transform().constant("Fallback message")
    .end()
    .to("mock:result");
----

And in XML DSL:
[source,xml]
----
<camelContext xmlns="http://camel.apache.org/schema/spring">
  <route>
    <from uri="direct:start"/>
    <hystrix>
      <to uri="http://fooservice.com/slow"/>
      <onFallback>
        <transform>
          <constant>Fallback message</constant>
        </transform>
      </onFallback>
    </hystrix>
    <to uri="mock:result"/>
  </route>
</camelContext>
----

See link:https://github.com/apache/camel/blob/master/camel-core/src/main/docs/eips/onFallback-eip.adoc[onFallback]

=== Other examples

You can find an example with the source code: link:https://github.com/apache/camel/tree/master/examples/camel-example-hystrix[camel-example-hystrix].
