Beanstalk component

Available in Camel 2.15

camel-beanstalk project provides a Camel component for job retrieval and post-processing of Beanstalk jobs.

You can find the detailed explanation of Beanstalk job lifecycle at Beanstalk protocol.

Dependencies

Maven users need to add the following dependency to their pom.xml

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-beanstalk</artifactId>
  <version>${camel-version}</version>
</dependency>

where ${camel-version} must be replaced by the actual version of Camel (2.15.0 or higher).

URI format

beanstalk://[host[:port]][/tube][?options]

You may omit either port or both host and port: for the Beanstalk defaults to be used (“localhost” and 11300). If you omit tube, Beanstalk component will use the tube with name “default”.

When listening, you may probably want to watch for jobs from several tubes. Just separate them with plus sign, e.g.

beanstalk://localhost:11300/tube1+tube2

Tube name will be URL decoded, so if your tube names include special characters like + or ?, you need to URL-encode them appropriately, or use the RAW syntax, see more details here.

By the way, you cannot specify several tubes when you are writing jobs into Beanstalk.

Common URI options

Producer UIR options

Producer behavior is affected by the command parameter which tells what to do with the job, it can be

Consumer UIR options

The consumer may delete the job immediately after reserving it or wait until Camel routes process it. While the first scenario is more like a “message queue”, the second is similar to “job queue”. This behavior is controlled by consumer.awaitJob parameter, which equals true by default (following Beanstalkd nature).

When synchronous, the consumer calls delete on successful job completion and calls bury on failure. You can choose which command to execute in the case of failure by specifying consumer.onFailure parameter in the URI. It can take values of bury, delete or release.

There is a boolean parameter consumer.useBlockIO which corresponds to the same parameter in JavaBeanstalkClient library. By default it is true.

Be careful when specifying release, as the failed job will immediately become available in the same tube and your consumer will try to acquire it again. You can release and specify jobDelay though.

Consumer Headers

The consumer stores a number of job headers in the Exchange message:

Examples

This Camel component lets you both request the jobs for processing and supply them to Beanstalkd daemon. Our simple demo routes may look like

from("beanstalk:testTube").
   log("Processing job #${property.beanstalk.jobId} with body ${in.body}").
   process(new Processor() {
     @Override
     public void process(Exchange exchange) {
       // try to make integer value out of body
       exchange.getIn().setBody( Integer.valueOf(exchange.getIn().getBody(classOf[String])) );
     }
   }).
   log("Parsed job #${property.beanstalk.jobId} to body ${in.body}");

from("timer:dig?period=30seconds").
   setBody(constant(10)).log("Kick ${in.body} buried/delayed tasks").
   to("beanstalk:testTube?command=kick");

In the first route we are listening for new jobs in tube “testTube”. When they are arriving, we are trying to parse integer value from the message body. If done successful, we log it and this successful exchange completion makes Camel component to delete this job from Beanstalk automatically. Contrary, when we cannot parse the job data, the exchange failed and the Camel component buries it by default, so that it can be processed later or probably we are going to inspect failed jobs manually.

So the second route periodically requests Beanstalk to kick 10 jobs out of buried and/or delayed state to the normal queue.