Update Cron expression in SpringBoot @Scheduled

Question

I have around 10 jobs scheduled with @Scheduled and a hardcoded cron expression like this:

@Scheduled(cron = "* * 1 * * *")
public void testMethod(){
    doSomething();
}

Now i want to be able to through the database update this cron expression and reschedule the specific job in runtime.

Does anyone knows how to do this?

Thanks

Not. That is not what cronjobs are used for / how they are supposed to work. — luk2302, Nov 10 '17 at 10:29
See e.g. how to changed `fixedDelay`: https://stackoverflow.com/q/14630539/2442804 - `cron` is even more complex. — luk2302, Nov 10 '17 at 10:30
Reimplement the entire cron job setup, debug into spring code and analyze where the annotation gets evaluated and try to reproduce that. — luk2302, Nov 10 '17 at 10:34
That is too much effort for this task. I thought that something was already done to handle this. Maybe create an answer with that so i can accept it — tiagocarvalho92, Nov 10 '17 at 10:41
If configuration is dynamic, how do you imagine an application should know, when to look for schedule in database? Each query to DB costs much — WeGa, Nov 10 '17 at 10:45
We could store the expression in a variable, and then in the GUI the user updates that variable, not that expensive i guess — tiagocarvalho92, Nov 10 '17 at 10:47

Mickael · Accepted Answer · 2017-11-10T12:31:49.953

11

If you want to configure the scheduling of job at runtime, I don't think you can use the annotation @Scheduled.

You can use your own scheduler instead from Spring documentation :

scheduler.schedule(task, new CronTrigger("0 15 9-17 * * MON-FRI"));

Then, if you want to change the configuration, you can cancel the scheduling and create a new one.

TaskScheduler return a ScheduledFuture that you should save somewhere and it can be cancelled with cancel(...) method.

edited Nov 10 '17 at 12:31

answered Nov 10 '17 at 10:47

Mickael

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... and keep track of the previous task and cancel its schedule as soon as you have a new schedule for it. – luk2302 Nov 10 '17 at 10:49
i'm trying to implement this and i came up with one question. Now that i won't have the annotation where in time and code should i load from the database all the cron expressions and schedule all the jobs? – tiagocarvalho92 Nov 10 '17 at 13:24
It's hard to say because I don't really know what your application is supposed to do. IMO, a good solution is to have a dedicated `Component` for this. Your `Component` will init all the jobs using `init-method` or `post-construct`. – Mickael Nov 10 '17 at 13:53
1

I found one way to do it ;) thanks for all the suggestions. – tiagocarvalho92 Nov 10 '17 at 14:33
@tiagocarvalho92 can you mention how you handled that, is it by using `Component`? – Yachitha Sandaruwan Feb 28 '23 at 07:10

score 4 · Answer 2 · edited May 29 '20 at 18:53

I think that @Scheduled no support this feature (must be interesting implement that). For advance scheduling feature you need to use quartz or other scheduler solution. My answer is based on Quartz Solution:

@Component
class ReschedulerComponent{

    @Autowired
    private SchedulerFactoryBean schedulerFactoryBean;

    public void reSchedule(){

    Trigger oldTriger = schedulerFactoryBean.getScheduler().getTrigger("my_custom_trigger");

        Trigger myNewTrigger = TriggerBuilder
                .newTrigger()
                .forJob(jobDetail) // Name of your job
                .withIdentity("my_custom_trigger")
                .startAt(myNewDATE)
                .withSchedule(SimpleScheduleBuilder.simpleSchedule().withMisfireHandlingInstructionFireNow())
                .build();

    schedulerFactoryBean.getScheduler().rescheduleJob(oldTriger.getKey(), myNewTrigger);
    }

}

Quick introduction: https://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/scheduling.html

score 1 · Answer 3 · answered Nov 10 '17 at 10:49

This can be done by specifying the cron expression in your property place holder as mentioned below. Add below code in @configuration class.

@Bean
    public PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {

        PropertySourcesPlaceholderConfigurer properties = new PropertySourcesPlaceholderConfigurer();
        properties.setLocation(new ClassPathResource("test.properties"));
    return properties;
    }

Now test.properties will be available in your placeholder. Test.properties shown below

variable.name.inside.properties= 00 39 05 * * *

Then inside your scheduler class add

    @Scheduled(cron = "${variable.name.inside.properties}")
public void testMethod(){
    doSomething();
}

with this solution you can't update the cron expression everytime you want :/ — tiagocarvalho92, Nov 10 '17 at 10:51
This perfectly worked for me , the values from the properties file can be picked now — Guruprasad, Apr 04 '22 at 03:56

WeGa · Answer 4 · 2017-11-10T10:48:26.183

0

If you want to configure schedule of the job, so that you don't need to change the code, I suggest you to extract value in property stored in some configuration.properties, then access to it in code with @Value.

UPD: found this topic, maybe you find it useful Spring Scheduler change cron expression dynamically

edited Nov 10 '17 at 10:48

answered Nov 10 '17 at 10:32

WeGa

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That's one option but i want to be able to change that in runtime. Your solution is the same as hardcoded values because it's not possible to change without a deploy – tiagocarvalho92 Nov 10 '17 at 10:33
Oh, I see. Please update your question with that information – WeGa Nov 10 '17 at 10:33
1

@WeGa that is already in the question: *"Now i want to be able to through the database update this cron expression and reschedule the specific job"*. – luk2302 Nov 10 '17 at 10:35
@luk2302, actually, it's only told about where OP wants to hold his configuration, and not how dynamically it should be. I just want to have more concise question)) – WeGa Nov 10 '17 at 10:42

score 0 · Answer 5 · answered Nov 10 '17 at 10:43

I think you should look at this resource You can programmatically create scheduled jobs. So if you annotate your method with @PostConstruct it should pick it when the application starts and run at the scheduled time

https://www.programcreek.com/java-api-examples/index.php?api=org.quartz.impl.triggers.SimpleTriggerImpl

http://www.quartz-scheduler.org/api/2.2.1/org/quartz/impl/triggers/SimpleTriggerImpl.html

Update Cron expression in SpringBoot @Scheduled

5 Answers5