Beanstalk

Since Camel 2.15

Both producer and consumer are supported

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.

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.

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

The component level is the highest level which holds general and common configurations that are inherited by the endpoints. For example a component may have security settings, credentials for authentication, urls for network connection and so forth.

Some components only have a few options, and others may have many. Because components typically have pre configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.

Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.

Configuring Endpoint Options

Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL as a type safe way of configuring endpoints.

A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.

The following two sections lists all the options, firstly for the component followed by the endpoint.

Component Options

The Beanstalk component supports 4 options, which are listed below.

Name Description Default Type

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

boolean

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

boolean

autowiredEnabled (advanced)

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

boolean

connectionSettingsFactory (advanced)

Custom ConnectionSettingsFactory. Specify which ConnectionSettingsFactory to use to make connections to Beanstalkd. Especially useful for unit testing without beanstalkd daemon (you can mock ConnectionSettings).

ConnectionSettingsFactory

Endpoint Options

The Beanstalk endpoint is configured using URI syntax:

beanstalk:connectionSettings

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

connectionSettings (common)

Connection settings host:port/tube.

String

Query Parameters (27 parameters)

Name Description Default Type

command (common)

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.

Enum values:

  • bury

  • release

  • put

  • touch

  • delete

  • kick

BeanstalkCommand

jobDelay (common)

Job delay in seconds.

int

jobPriority (common)

Job priority. (0 is the highest, see Beanstalk protocol).

1000

long

jobTimeToRun (common)

Job time to run in seconds. (when 0, the beanstalkd daemon raises it to 1 automatically, see Beanstalk protocol).

60

int

awaitJob (consumer)

Whether to wait for job to complete before ack the job from beanstalk.

true

boolean

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

boolean

onFailure (consumer)

Command to use when processing failed.

Enum values:

  • bury

  • release

  • put

  • touch

  • delete

  • kick

BeanstalkCommand

sendEmptyMessageWhenIdle (consumer)

If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.

boolean

useBlockIO (consumer)

Whether to use blockIO.

true

boolean

exceptionHandler (consumer (advanced))

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer (advanced))

Sets the exchange pattern when the consumer creates an exchange.

Enum values:

  • InOnly

  • InOut

  • InOptionalOut

ExchangePattern

pollStrategy (consumer (advanced))

A pluggable org.apache.camel.PollingConsumerPollingStrategy allowing you to provide your custom implementation to control error handling usually occurred during the poll operation before an Exchange have been created and being routed in Camel.

PollingConsumerPollStrategy

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

boolean

backoffErrorThreshold (scheduler)

The number of subsequent error polls (failed due some error) that should happen before the backoffMultipler should kick-in.

int

backoffIdleThreshold (scheduler)

The number of subsequent idle polls that should happen before the backoffMultipler should kick-in.

int

backoffMultiplier (scheduler)

To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then backoffIdleThreshold and/or backoffErrorThreshold must also be configured.

int

delay (scheduler)

Milliseconds before the next poll.

500

long

greedy (scheduler)

If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the previous run polled 1 or more messages.

boolean

initialDelay (scheduler)

Milliseconds before the first poll starts.

1000

long

repeatCount (scheduler)

Specifies a maximum limit of number of fires. So if you set it to 1, the scheduler will only fire once. If you set it to 5, it will only fire five times. A value of zero or negative means fire forever.

long

runLoggingLevel (scheduler)

The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.

Enum values:

  • TRACE

  • DEBUG

  • INFO

  • WARN

  • ERROR

  • OFF

TRACE

LoggingLevel

scheduledExecutorService (scheduler)

Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool.

ScheduledExecutorService

scheduler (scheduler)

To use a cron scheduler from either camel-spring or camel-quartz component. Use value spring or quartz for built in scheduler.

none

Object

schedulerProperties (scheduler)

To configure additional properties when using a custom scheduler or any of the Quartz, Spring based scheduler.

Map

startScheduler (scheduler)

Whether the scheduler should be auto started.

true

boolean

timeUnit (scheduler)

Time unit for initialDelay and delay options.

Enum values:

  • NANOSECONDS

  • MICROSECONDS

  • MILLISECONDS

  • SECONDS

  • MINUTES

  • HOURS

  • DAYS

MILLISECONDS

TimeUnit

useFixedDelay (scheduler)

Controls if fixed delay or fixed rate is used. See ScheduledExecutorService in JDK for details.

true

boolean

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

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 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 onFailure parameter in the URI. It can take values of bury, delete or release.

There is a boolean parameter 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 beanstalk consumer is a Scheduled Polling Consumer which means there is more options you can configure, such as how frequent the consumer should poll. For more details see Polling Consumer.

Consumer Headers

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

Property Type 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

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

Spring Boot Auto-Configuration

When using beanstalk 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-beanstalk-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 5 options, which are listed below.

Name Description Default Type

camel.component.beanstalk.autowired-enabled

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

Boolean

camel.component.beanstalk.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.beanstalk.connection-settings-factory

Custom ConnectionSettingsFactory. Specify which ConnectionSettingsFactory to use to make connections to Beanstalkd. Especially useful for unit testing without beanstalkd daemon (you can mock ConnectionSettings). The option is a org.apache.camel.component.beanstalk.ConnectionSettingsFactory type.

ConnectionSettingsFactory

camel.component.beanstalk.enabled

Whether to enable auto configuration of the beanstalk component. This is enabled by default.

Boolean

camel.component.beanstalk.lazy-start-producer

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

Boolean
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