This component will be part of Apache Camel 2.15

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Camel component for Beanstalk

Beanstalk is a simple work queue service.

Apache Camel is an integration framework.

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

Example

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 failes 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.

Component URI format

The component URI is

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

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.

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

Parameters

Common parameters are listed below along with the message header names. Message header always takes the highest precedence over the URI.

Parameter	Header	Unit	Default
jobPriority	beanstalk.priority	integer	1000 (0 is the highest, see Beanstalk protocol)
jobDelay	beanstalk.delay	seconds	0
jobTimeToRun	beanstalk.timeToRun	seconds	60 (when 0, the beanstalkd daemon raises it to 1 automatically, see Beanstalk protocol)

Producer parameters

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

• put means to put the job into Beanstalk. Job body is specified in the Camel message body. Job ID will be returned in beanstalk.jobId message header.
• delete, release, touch or bury expect Job ID in the message header beanstalk.jobId. Result of the operation is returned in beanstalk.result message header
• kick expects the number of jobs to kick in the message body and returns the number of jobs actually kicked out in the message header beanstalk.result.

Consumer parameters

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.

The consumer stores a number of job properties in the Exchange:

Property	Unit	Description
beanstalk.jobId	long	Job ID
beanstalk.tube	string	the name of the tube that contains this job
beanstalk.state	string	“ready” or “delayed” or “reserved” or “buried” (must be “reserved”)
beanstalk.priority	long	the priority value set
beanstalk.age	int	the time in seconds since the put command that created this job
beanstalk.time-left	int	the number of seconds left until the server puts this job into the ready queue
beanstalk.timeouts	int	the number of times this job has timed out during a reservation
beanstalk.releases	int	the number of times a client has released this job from a reservation
beanstalk.buries	int	the number of times this job has been buried
beanstalk.kicks	int	the number of times this job has been kicked

Using

For Apache Camel 2.11.x :

<dependency>
  <groupId>com.osinka.camel</groupId>
  <artifactId>camel-beanstalk</artifactId>
  <version>1.7.0</version>
</dependency>

For Apache Camel 2.10.x :

<dependency>
  <groupId>com.osinka.camel</groupId>
  <artifactId>camel-beanstalk</artifactId>
  <version>1.6.0</version>
</dependency>

License

This component is distributed under Apache License 2.0