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
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:
Component | Description | Default (provided by DefaultTaskConfigurer ) |
---|---|---|
| The implementation of the |
|
| The implementation of the |
|
| A transaction manager to be used when executing updates for tasks. |
|
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):
spring.cloud.task.name
.ApplicationContext#getId
).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:
onTaskStartup
- prior to the storing the TaskExecution
into the TaskRepository
onTaskEnd
- prior to the updating of the TaskExecution
entry in the TaskRepository
marking the final state of the task.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:
@BeforeTask
- prior to the storing the TaskExecution
into the TaskRepository
@AfterTask
- prior to the updating of the TaskExecution
entry in the TaskRepository
marking the final state of the task.@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) { } }