8. Configuration

Spring Cloud Task provides an out of the box configuration as defined in the DefaultTaskConfigurer and SimpleTaskConfiguration. This section will walk through the defaults as well as how to customize Spring Cloud Task for your needs

8.1 DataSource

Spring Cloud Task utilizes a datasource for storing the results of task executions. By default, we provide an in memory instance of H2 to provide a simple method of bootstrapping development. However, in a production environment, you’ll want to configure your own DataSource.

If your application utilizes only a single DataSource and that will serve as both your business schema as well as the task repository, all you need to do is provide any DataSource (via Spring Boot’s configuration conventions is the easiest way). This will be automatically used by Spring Cloud Task for the repository.

If your application utilizes more than one DataSource, you’ll need to configure the task repository with the appropriate DataSource. This customization can be done via an implementation of the TaskConfigurer.

8.2 TaskConfigurer

The TaskConfigurer is a strategy interface allowing for users to customize the way components of Spring Cloud Task are configured. By default, we provide the DefaultTaskConfigurer that provides logical defaults (Map based in memory components useful for development if no DataSource is provided and JDBC based components if there is a DataSource available.

The TaskConfigurer allows the configuration of three main components:

ComponentDescriptionDefault (provided by DefaultTaskConfigurer)

TaskRepository

The implementation of the TaskRepository to be used.

SimpleTaskRepository

TaskExplorer

The implementation of the TaskExplorer (a component for read only access to the task repository) to be used.

SimpleTaskExplorer

PlatformTransactionManager

A transaction manager to be used when executing updates for tasks.

DataSourceTransactionManager if a DataSource is used, ResourcelessTransactionManager if it is not.

8.3 Task Name

In most cases, the name of the task will be the application name as configured via Spring Boot. However, there are some cases, where you may want to map the run of a task to a different name. Spring Data Flow is an example of this (where you want the task to be run with the name of the task definition). Because of this, we offer the ability to customize how the task is named via the TaskNameResolver interface.

By default, Spring Cloud Task provides the SimpleTaskNameResolver which will use the following options (in order of precedence):

  1. A Spring Boot property (configured any of the ways Spring Boot allows) spring.cloud.task.name.
  2. The application name as resolved using Spring Boot’s rules (obtained via ApplicationContext#getId).

8.4 Task Execution Listener

Allows a user to register listeners for specific events that occur during the task lifecycle. This is done by creating a class that implements the TaskExecutionListener interface. The class that implements the TaskExecutionListener interface will be notified for the following events:

  1. onTaskStartup - prior to the storing the TaskExecution into the TaskRepository
  2. onTaskEnd - prior to the updating of the TaskExecution entry in the TaskRepository marking the final state of the task.
  3. onTaskFailed - prior to the onTaskEnd method being invoked when an unhandled exception is thrown by the task.

Spring Cloud Task also allows a user add TaskExecution Listeners to methods within a bean by using the following method annotations:

  1. @BeforeTask - prior to the storing the TaskExecution into the TaskRepository
  2. @AfterTask - prior to the updating of the TaskExecution entry in the TaskRepository marking the final state of the task.
  3. @FailedTask - prior to the @AfterTask method being invoked when an unhandled exception is thrown by the task.
 public class MyBean {

	@BeforeTask
	public void methodA(TaskExecution taskExecution) {
	}

	@AfterTask
	public void methodB(TaskExecution taskExecution) {
	}

	@FailedTask
	public void methodC(TaskExecution taskExecution, Throwable throwable) {
	}
}