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.

One modifiable property of the TaskRepository is the table prefix for the task tables. By default they are all prefaced with TASK_. TASK_EXECUTION and TASK_EXECUTION_PARAMS are two examples. However, there are potential reasons to modify this prefix. If the schema names needs to be prepended to the table names, or if more than one set of task tables is needed within the same schema, then the table prefix will need to be changed. This is done by setting the spring.cloud.task.tablePrefix to the prefix that is required.

 spring.cloud.task.tablePrefix=<yourPrefix>

In cases where you are creating the task tables and do not wish for Spring Cloud Task to create them at task startup set the spring.cloud.task.initialize.enable property to false. It is currently defaulted to true.

 spring.cloud.task.initialize.enable=<true or false>

In some cases a user wants to allow for the time difference between when a task is requested and when the infrastructure actually launches it. Spring Cloud Task allows a user to create a TaskExecution at the time the task is requested. Then pass the execution ID of the generated TaskExecution to the task so that it can update the TaskExecution through the task’s lifecycle.

The TaskExecution can be created by calling the createTaskExecution method on an implementation of the TaskRepository that references the datastore storing the TaskExecutions.

In order to configure your Task to use a generated TaskExecutionId add the following property:

 spring.cloud.task.executionid=<yourtaskId>

Spring Cloud Task allows a user to store an external task Id for each TaskExecution. An example of this would be a task id that is provided by Cloud Foundry when a task is launched on the platform. In order to configure your Task to use a generated TaskExecutionId add the following property:

spring.cloud.task.external-execution-id=<externalTaskId>

Spring Cloud Task allows a user to store an parent task Id for each TaskExecution. An example of this would be a task that executes another task or tasks and the user would like to store what task launched the child tasks. In order to configure your Task to set a parent TaskExecutionId add the following property on the child task:

spring.cloud.task.parent-execution-id=<parentExecutionTaskId>

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:

Customizing any of the above is accomplished via a custom implementation of the TaskConfigurer interface. Typically, extending the DefaultTaskConfigurer (which is provided out of the box if a TaskConfigurer is not found) and overriding the required getter is sufficient, however, implementing your own from scratch may be required.

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):

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:

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

 public class MyBean {

	@BeforeTask
	public void methodA(TaskExecution taskExecution) {
	}

	@AfterTask
	public void methodB(TaskExecution taskExecution) {
	}

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

@AfterTask
public void afterMe(TaskExecution taskExecution) {
    taskExecution.setExitMessage("AFTER EXIT MESSAGE");
}

Allows a user to establish that only one task with a given task name can be run at a time. To do this the user establishes the task name and sets spring.cloud.task.singleInstanceEnabled=true for each task execution. While the first task execution is running, any other time user tries to run a task with the same task name and spring.cloud.task.singleInstanceEnabled=true the task will fail with the following error message Task with name "application" is already running. The default for spring.cloud.task.singleInstanceEnabled is false.

 spring.cloud.task.singleInstanceEnabled=<true or false>

In order for this feature to be used you must include the following Spring Integration dependencies to your application:

---
<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-core</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-jdbc</artifactId>
</dependency>
---