3.9.14.2.1. Task Registration

Tasks are registered in the SYS_SCHEDULED_TASK database table, which corresponds to the ScheduledTask entity. There are browser and editor screens for working with tasks, which are available through the Administration → Scheduled Tasks menu.

Task attributes are described below:

  • Defined by – describes which software object implements the task. Possible values are:

    • Bean – the task is implemented by a method of a Spring bean. Additional attributes:

      • Bean name – the name of the Spring bean.

        The bean is listed and available for selection only if it is defined in the core module and has an interface, which contains methods appropriate for invocation from the task. Beans without an interface are not supported.

      • Method name – the bean interface method that is executed. The method must either have no parameters, or all parameters must be of String type. The return type of the method can either be void or String. In the latter case the returning value will be stored in the executions table (see Log finish below).

      • Method parameters – the parameters of the chosen method. Only String type parameters are supported.

    • Class – the task is a class that implements the java.util.concurrent.Callable interface. The class must have a public constructor without parameters. Additional attributes:

      • Class name – the name of the class.

    • Script – the task is a Groovy script. The script is executed by Scripting.runGroovyScript(). Additional attributes:

      • Script name – the name of the script.

  • User name – the name of a user on whose behalf the task will be executed. If not specified, the task will be executed on behalf of the user specified in the cuba.jmxUserLogin application property.

  • Singleton – indicates that the task is a singleton, i.e. should be run only on one application server.

  • Scheduling type – the means of task scheduling:

    • Cron – Cron expression is a sequence of six fields, separated by spaces: second, minute, hour, day, month, day of a week. The month and the day of a week can be represented by the first three letters of their English names. Examples:

      • 0 0 * * * * – the beginning of every hour of every day

      • */10 * * * * * – every 10 seconds

      • 0 0 8-10 * * * – every day at 8, 9 and 10 o’clock

      • 0 0/30 8-10 * * * – every day at 8:00, 8:30, 9:00, 9:30 and 10 o’clock

      • 0 0 9-17 * * MON-FRI – every hour from 9 to 17 on working days

      • 0 0 0 25 DEC ? – every Christmas at midnight.

    • Period – task execution interval in seconds.

    • Fixed Delay – task will be executed with the specified in Period delay after completion of the preceding execution.

  • Period – task execution interval or delay in seconds if Scheduling type is Period or Fixed Delay.

  • Start date – the date/time of the first launch. If not specified, the task is launched immediately on server startup. If specified, the task is launched at startDate + period * N, where N is an integer.

    It is reasonable to specify Start date only for "infrequent" tasks, i.e. running once an hour, once a day, etc.

  • Timeout – time in seconds, upon the expiration of which it is considered that the execution of the task is completed, regardless of whether there is information about task completion or not. If the timeout is not set explicitly, it is assumed to be 3 hours.

    It is recommended to always set the timeout to a realistic value for singleton tasks working in a clustered deployment. With the standard value, if a cluster node executing a task goes down, other nodes will wait for 3 hours before starting a new execution.

  • Time frame – if Start date is specified, Time frame defines the time window in seconds, during which the task will be launched after startDate + period * N time expires. If Time frame is not specified explicitly, it is equal to period / 2.

    If Start date is not specified, Time frame is ignored, i.e. the task will be launched at any time after Period since the previous execution of the task expires.

  • Start delay - delay of execution in seconds after the server is started and scheduling is activated. Set this parameter for a heavy task if you think that it slows down the server startup process.

  • Permitted servers – the list of comma-separated identifiers of servers that have the permission to run this task. If the list is not specified, the task may be executed on any server.

    For singleton tasks, the order of the servers in the list defines the execution priority: the first server has a higher priority than the last. The server with a higher priority will intercept the execution of the singleton as follows: if the server with a higher priority detects that the task has been previously executed by a server with lower priority, it launches the task regardless of whether the Period has elapsed or not.

    Server priority works only if Scheduling type is Period and the Start date attribute is not specified. Otherwise, start occurs at the same time and the interception is impossible.

  • Log start – flags if the task launch should be registered in the SYS_SCHEDULED_EXECUTION table, which corresponds to the ScheduledExecution entity.

    In the current implementation, if the task is a singleton, the launch is registered regardless of this flag.

  • Log finish – flags if the task completion should be registered in the SYS_SCHEDULED_EXECUTION table, which corresponds to the ScheduledExecution entity.

    In the current implementation, if the task is a singleton, completion is registered regardless of this flag.

  • Description – an arbitrary text description of the task.

The task also has activity flag, which can be set in the tasks list screen. Inactive tasks are ignored.