Kestrel Component
The Kestrel component allows messages to be sent to a Kestrel queue, or messages to be consumed from a Kestrel queue using the Spymemcached client.
URI format
Where queuename is a Kestrel queue name. The addresslist part of the URI may include one or more host:port pairs. For example, to connect to the queue foo on kserver01:22133, use:
If the addresslist is omitted, localhost:22133 is assumed, i.e.:
Likewise, if a port is omitted from a host:port pair in addresslist, the default port 22133 is assumed, i.e.:
Here is an example of a Kestrel endpoint URI used for producing to a clustered queue:
Here is an example of a Kestrel endpoint URI used for consuming concurrently from a queue:
Options
You can configure properties on each Kestrel endpoint individually by specifying them in the ?parameters portion of the endpoint URI. Any ?parameters that are omitted will default to what is configured on the KestrelComponent's base KestrelConfiguration. The following properties may be set on KestrelConfiguration and/or each individual endpoint:
| Option |
Default Value |
Description |
| concurrentConsumers |
1 |
Specifies the number of concurrent consumer threads. |
| waitTimeMs |
100 |
Specifies the /t=... wait time passed to Kestrel on GET requests. |
NOTE: If waitTimeMs is set to zero or a negative value, the //t=... specifier does not get passed to the server on GET requests. In order to prevent "tight looping" in the polling phase, this component will do a Thread.sleep(100) whenever nothing is returned from the GET request (only when nothing is returned).
Configuring the Kestrel component using Spring XML
The simplest form of explicit configuration is as follows:
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd">
<bean id="kestrel" class="org.apache.camel.component.kestrel.KestrelComponent"/>
<camelContext xmlns="http://camel.apache.org/schema/spring">
</camelContext>
</beans>
That will enable the Kestrel component with all default settings, i.e. it will use localhost:22133, 100ms wait time, and a single non-concurrent consumer by default.
To use specific options in the base configuration (which supplies configuration to endpoints whose ?properties are not specified), you can set up a KestrelConfiguration POJO as follows:
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd">
<bean id="kestrelConfiguration" class="org.apache.camel.component.kestrel.KestrelConfiguration">
<property name="addresses" value="kestrel01:22133"/>
<property name="waitTimeMs" value="100"/>
<property name="concurrentConsumers" value="1"/>
</bean>
<bean id="kestrel" class="org.apache.camel.component.kestrel.KestrelComponent">
<property name="configuration" ref="kestrelConfiguration"/>
</bean>
<camelContext xmlns="http://camel.apache.org/schema/spring">
</camelContext>
</beans>
Getting Component JAR
You will need these dependencies
spymemcached
You must have the spymemcached jar on your classpath. Here is a snippet you can use in your pom.xml:
<dependency>
<groupId>spy</groupId>
<artifactId>memcached</artifactId>
<version>2.5</version>
</dependency>
See Also
