如何定期安排任务？

Question

Is there any native library or third party support like ScheduledExecutorService by java native library at go lang for production use case?

Please find the code snippet in java 1.8 :

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;


public class TaskScheduler {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Runnable runnable = ()-> {
                // task to run goes here
                System.out.println("Hello !!");
        };
        ScheduledExecutorService service = Executors.newScheduledThreadPool(1);
        service.scheduleAtFixedRate(runnable, 0, 1, TimeUnit.SECONDS);

    }

}

It will print Hello !! in every one second.

Answer 1

No need to use 3rd party library to achieve that. Simply take the advantage of goroutine and use available time.Sleep() API from time package, then the very same result can be achieved.

Example:

go func() {
    for true {
        fmt.Println("Hello !!")
        time.Sleep(1 * time.Second)
    }
}()

Playground: https://play.golang.org/p/IMV_IAt-VQX

---

Example using ticker #1

As per suggestion from Siddhanta. Here is one example to achieve the same result by using ticker (taken from go documentation page of ticker, with some modifications following your requirement).

done := make(chan bool)
ticker := time.NewTicker(1 * time.Second)

go func() {
    for {
        select {
        case <-done:
            ticker.Stop()
            return
        case <-ticker.C:
            fmt.Println("Hello !!")
        }
    }
}()

// wait for 10 seconds
time.Sleep(10 *time.Second)
done <- true

The ticker time information (the time when the Hello !! executed) can be taken from ticker.C channel.

case t := <-ticker.C:
    fmt.Println(t)

Playground: https://play.golang.org/p/TN2M-AMr39L

---

Example using ticker #2

Another simplified example of ticker, taken from https://gobyexample.com/tickers

ticker := time.NewTicker(1 * time.Second)
go func() {
    for t := range ticker.C {
        _ = t // we don't print the ticker time, so assign this `t` variable to underscore `_` to avoid error
        fmt.Println("Hello !!")
    }
}()

// wait for 10 seconds
time.Sleep(10 *time.Second)
ticker.Stop()