When executing a Spring Batch job through a task, Spring Cloud Task can be configured to emit informational messages based on the Spring Batch listeners available in Spring Batch. Specifically, the following Spring Batch listeners are autoconfigured into each batch job and emit messages on the associated Spring Cloud Stream channels when run through Spring Cloud Task:
JobExecutionListenerlistens forjob-execution-eventsStepExecutionListenerlistens forstep-execution-eventsChunkListenerlistens forchunk-eventsItemReadListenerlistens foritem-read-eventsItemProcessListenerlistens foritem-process-eventsItemWriteListenerlistens foritem-write-eventsSkipListenerlistens forskip-events
These listeners are autoconfigured into any AbstractJob when the appropriate
beans (a Job and a TaskLifecycleListener) exist in the context. Configuration to
listen to these events is handled the same way binding to any other Spring
Cloud Stream channel is done. Our task (the one running the batch job) serves as a
Source, with the listening applications serving as either a Processor or a Sink.
An example could be to have an application listening to the job-execution-events channel
for the start and stop of a job. To configure the listening application, you would
configure the input to be job-execution-events as follows:
spring.cloud.stream.bindings.input.destination=job-execution-events
![[Note]](images/note.png) | Note |
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A binder implementation is also required to be on the classpath. |
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A sample batch event application can be found in the samples module of the Spring Cloud Task Project, here. |
One of the options that Spring Cloud Task offers for batch events is the ability to alter
the channel to which a specific listener can emit its messages. To do so, use the
following configuration:
spring.cloud.stream.bindings.<the channel>.destination=<new destination>. For example,
if StepExecutionListener needs to emit its messages to another channel called
my-step-execution-events instead of the default step-execution-events, you can add the
following configuration:
spring.cloud.stream.bindings.step-execution-events.destination=my-step-execution-events
To disable the listener functionality for all batch events, use the following configuration:
spring.cloud.task.batch.events.enabled=false
To disable a specific batch event, use the following configuration:
spring.cloud.task.batch.events.<batch event listener>.enabled=false:
The following listing shows individual listeners that you can disable:
spring.cloud.task.batch.events.job-execution.enabled=false
spring.cloud.task.batch.events.step-execution.enabled=false
spring.cloud.task.batch.events.chunk.enabled=false
spring.cloud.task.batch.events.item-read.enabled=false
spring.cloud.task.batch.events.item-process.enabled=false
spring.cloud.task.batch.events.item-write.enabled=false
spring.cloud.task.batch.events.skip.enabled=falseBy default, batch events have Ordered.LOWEST_PRECEDENCE. To change this value (for
example, to 5 ), use the following configuration:
spring.cloud.task.batch.events.job-execution-order=5 spring.cloud.task.batch.events.step-execution-order=5 spring.cloud.task.batch.events.chunk-order=5 spring.cloud.task.batch.events.item-read-order=5 spring.cloud.task.batch.events.item-process-order=5 spring.cloud.task.batch.events.item-write-order=5 spring.cloud.task.batch.events.skip-order=5