How to cancel kotlin coroutine if it takes longer than a certain period of time?

Question

I want to cancel kotlin coroutine if it takes longer than a certain time.

This is what I am doing:

    GlobalScope.launch(Dispatchers.Main) {
        val userOne = async(Dispatchers.IO) { Page_Load_Times() }.await()

        Log.d("Tag", "Long Running task: $userOne")
    }


suspend fun Page_Load_Times(): String? {
    val startTime: Long = 0
    var endTime: Long = 0

    delay(5000) // if it is greater a certain time, eg 1000, I want to cancel the thread and return 

    return "Hey there"

}

How to cancel kotlin coroutine if it takes longer than a certain period of time?

Answer 1

There are built in suspending functions for that: withTimeout and withTimeoutOrNull.

Just invoke it with specified timeout:

GlobalScope.launch(Dispatchers.Main) {
    val userOne = withContext(Dispatchers.IO) {
        withTimeoutOrNull(5000) { Page_Load_Times() }
    }

    Log.d("Tag", "Long Running task: $userOne")
}

Then your userOne becomes null if it times out.

Answer 2

I want to share a good example with you through the documentation. I hope it inspires.

 val job = launch {
        repeat(1000) { i ->
            println("job: I'm sleeping $i ...")
            delay(500L)
        }
    }
    delay(1300L) // delay a bit
    println("main: I'm tired of waiting!")
    job.cancel() // cancels the job
    job.join() // waits for job's completion 
    println("main: Now I can quit.")

It produces the following output:

job: I'm sleeping 0 ...
job: I'm sleeping 1 ...
job: I'm sleeping 2 ...
main: I'm tired of waiting!
main: Now I can quit.

Source-Doc