= Control Bus Component
:doctitle: Control Bus
:shortname: controlbus
:artifactid: camel-controlbus
:description: Manage and monitor Camel routes.
:since: 2.11
:supportlevel: Stable
:component-header: Only producer is supported
:core:
//Manually maintained attributes
:camel-spring-boot-name: controlbus

*Since Camel {since}*

*{component-header}*

The http://www.eaipatterns.com/ControlBus.html[Control Bus] from the
EIP patterns allows for the
integration system to be monitored and managed from within the
framework.

image::control_bus.png[image]

Use a Control Bus to manage an enterprise integration system. The
Control Bus uses the same messaging mechanism used by the application
data, but uses separate channels to transmit data that is relevant to
the management of components involved in the message flow.

In Camel you can manage and monitor using JMX, or
by using a Java API from the `CamelContext`, or from the
`org.apache.camel.api.management` package, +
 or use the event notifier which has an example
here.

The ControlBus component provides easy management of Camel
applications based on the xref:controlbus-component.adoc[Control Bus] EIP
pattern. 
For example, by sending a message to an Endpoint
you can control the lifecycle of routes, or gather performance
statistics.

----
controlbus:command[?options]
----

Where *command* can be any string to identify which type of command to
use.

== Commands

[width="100%",cols="10%,90%",options="header",]
|===
|Command |Description

|`route` |To control routes using the `routeId` and `action` parameter.

|`language` |Allows you to specify a xref:language-component.adoc[Language] to use for
evaluating the message body. If there is any result from the evaluation,
then the result is put in the message body.
|===


// component-configure options: START

// component-configure options: END

// component options: START
include::partial$component-configure-options.adoc[]
include::partial$component-endpoint-options.adoc[]
// component options: END

// endpoint options: START

// endpoint options: END


== Using route command

The route command allows you to do common tasks on a given route very
easily, for example to start a route, you can send an empty message to
this endpoint:

[source,java]
----
template.sendBody("controlbus:route?routeId=foo&action=start", null);
----

To get the status of the route, you can do:

[source,java]
----
String status = template.requestBody("controlbus:route?routeId=foo&action=status", null, String.class);
----

[[ControlBus-Gettingperformancestatistics]]
== Getting performance statistics

This requires JMX to be enabled (is by default) then you can get the
performance statistics per route, or for the
CamelContext. For example to get the statistics for
a route named foo, we can do:

[source,java]
----
String xml = template.requestBody("controlbus:route?routeId=foo&action=stats", null, String.class);
----

The returned statistics is in XML format. Its the same data you can get
from JMX with the `dumpRouteStatsAsXml` operation on the
`ManagedRouteMBean`.

To get statistics for the entire CamelContext you
just omit the routeId parameter as shown below:

[source,java]
----
String xml = template.requestBody("controlbus:route?action=stats", null, String.class);
----

== Using Simple language

You can use the xref:languages:simple-language.adoc[Simple] language with the control bus,
for example to stop a specific route, you can send a message to the
`"controlbus:language:simple"` endpoint containing the following
message:

[source,java]
----
template.sendBody("controlbus:language:simple", "${camelContext.getRouteController().stopRoute('myRoute')}");
----

As this is a void operation, no result is returned. However, if you want
the route status you can do:

[source,java]
----
String status = template.requestBody("controlbus:language:simple", "${camelContext.getRouteStatus('myRoute')}", String.class);
----

It's easier to use the `route` command to control lifecycle of
routes. The `language` command allows you to execute a language script
that has stronger powers such as xref:languages:groovy-language.adoc[Groovy] or to some
extend the xref:languages:simple-language.adoc[Simple] language.

For example to shutdown Camel itself you can do:

[source,java]
----
template.sendBody("controlbus:language:simple?async=true", "${camelContext.stop()}");
----

We use `async=true` to stop Camel asynchronously as otherwise we
would be trying to stop Camel while it was in-flight processing the
message we sent to the control bus component.

[TIP]
====
You can also use other languages such as xref:languages:groovy-language.adoc[Groovy], etc.
====


include::spring-boot:partial$starter.adoc[]
