Add execution metadata to scheduled tasks

[bclozel]

@enesify requested an enhancement on Spring Boot, where actuator endpoints could provide more information about scheduled tasks.

Currently, the /actuator/scheduledtasks actuator endpoint provides information about scheduled tasks, including their type, target and scheduling information.

The enhancement request would require more metadata being present on the tasks themselves, such as:

• last Execution Time
• last Execution Status
• next Execution Time

The issue also requests the ability to change a cron expression or to manually trigger a task. For that, Spring Boot would need a unique identifier for each task, which they don't have at the moment.

See spring-projects/spring-boot#17585 for context.

[snicoll]

The issue also requests the ability to change a cron expression or to manually trigger a task. For that, Spring Boot would need a unique identifier for each task, which they don't have at the moment.

We'd rather expose the metadata only for now as a first step.