s-evgheni
commented
2 years ago Furthermore there seems to be a bug in the framework which will allow you to perform dynamic CRON scheduling if you manage to schedule a delayed task before it with the same set of primary keys. Like this:
@GetMapping(value = "/dbs-enque-cron-job", produces = {MediaType.TEXT_PLAIN_VALUE})
public String dbsNewCronJob(@RequestParam(value = "cron_expression", defaultValue = "0 */1 * * * *") String cronExpression) {
log.info("Provided cron value:" + cronExpression);
//get task definition
Task<PlainScheduleAndData> task = taskConfiguration.dynamicCronTask();
//define run schedule
Schedule cron = Schedules.cron(cronExpression);
PlainScheduleAndData when = new PlainScheduleAndData(cron);
//create instance based on task definition and run schedule
String randomTaskInstanceId = UUID.randomUUID().toString();
SchedulableInstance<?> taskInstanceOne = task.schedulableInstance(randomTaskInstanceId, new PlainScheduleAndData(Schedules.fixedDelay(Duration.ofSeconds(1))));
SchedulableInstance<?> taskInstanceTwo = task.schedulableInstance(randomTaskInstanceId, when);
//schedule instance for recurring execution (e.g: add to Postgres scheduled_tasks table)
//1st add serializable FixedDelay task instance
this.schedulingService.getDbScheduler().schedule(taskInstanceOne);
//2nd override FixedDelay task instance with a cron expression
this.schedulingService.getDbScheduler().schedule(taskInstanceTwo);
return "Recurring Job enqueued with an id of: " + taskInstanceTwo.getId() + " and cron schedule:" + when.getSchedule().toString();
}So essentially in this scenario we will end up with running taskInstanceTwo logic on taskInstanceOne schedule.
kagkarlsson
@kagkarlsson I was looking at your library, trying to figure out how would one go about creating dynamic CRON task ?
My current understanding is that due to the fact that CronSchedule is not Seriallizable it is not a good fit for this kind of operation.
Here is what I was trying to achieve.
In a SpringBoot app define task configuration such us:
Try to schedule the task above from a Spring controller:
Outcome: