Chapter 16. Control Bus

Camel components are configured on two separate levels:

The Control Bus component supports 2 options, which are listed below.

The Control Bus endpoint is configured using URI syntax:

controlbus:command:language

with the following path and query parameters:

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:

template.sendBody("controlbus:route?routeId=foo&action=start", null);

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

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

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:

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:

String xml = template.requestBody("controlbus:route?action=stats", null, String.class);

You can use the 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:

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:

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 Groovy or to some extend the Simple language.

For example to shutdown Camel itself you can do:

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.

When using controlbus with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-controlbus-starter</artifactId>
</dependency>

The component supports 3 options, which are listed below.