grails

Is it possible to run a cron job on demand in services? The job will be called once after an hour, for example.

Quartz supports kicking off arbitrarily so yeah

With the Grails Quartz Plugin, schedule the job once an hour: 

package <http://myapp.jobs|myapp.jobs>

import grails.plugins.quartz.Job

class MyJob implements Job {

    static triggers = {
        cron name: 'hourlyTrigger', cronExpression: '0 0 * * * ?'
    }

    def execute(context) {
        println "Eseguito alle ${new Date()}"
    }
}

Then trigger it just once in your app:

MyJob.triggerNow()

I've used <https://www.jobrunr.io/en/documentation/configuration/spring/> in Grails 5, 6 and 7.