How to schedule tasks in Ktor microservice app

Question

I am trying to schedule a task in my Ktor application, however I have not been able to find anything online about how to do this. Does anyone have any recommendations or been able to do this before?

Standard

Answer 1

Ktor doesn't have a built-in scheduler, so you'd have to implement your own.

I've written a small class using Java's Executors for this task for myself, you might find it useful:

class Scheduler(private val task: Runnable) {
    private val executor = Executors.newScheduledThreadPool(1)!!

    fun scheduleExecution(every: Every) {

        val taskWrapper = Runnable {
            task.run()
        }

        executor.scheduleWithFixedDelay(taskWrapper, every.n, every.n, every.unit)
    }


    fun stop() {
        executor.shutdown()

        try {
            executor.awaitTermination(1, TimeUnit.HOURS)
        } catch (e: InterruptedException) {
        }

    }
}

data class Every(val n: Long, val unit: TimeUnit)

Knowitall

awesome this works. Currently I am starting the Runnable when an api call is made. Is there a way to have the runnable running at all times? – Standard

Could you please elaborate on what you mean by "runnable running at all times"? You mean as soon as you create Scheduler? You could create init {} block and scheduleExecution in it – Knowitall

Evgeny, please provide how to call it from running thread – Courson