play.go

package main

import (
	"fmt"
	"time"
)

func timeroutTimer() {
	fmt.Println("Waiting for timer")
	c := time.After(10 * time.Second)
	<-c
	fmt.Println("Timer reached")
}

func cancelTimer() {
	timer := time.NewTimer(10 * time.Second)
	defer timer.Stop()

	a := make(chan int)

	go func() {
		time.Sleep(2 * time.Second)
		a <- 8
	}()

	select {
	case <-timer.C:
		fmt.Println("10 seconds reached")
	case n := <-a:
		// timer.Stop()
		fmt.Printf("Get %d from a, cancel timer", n)
	}

}

func async_chan() {
	ch := make(chan int)
	for i := 0; i < 10; i++ {
		go func(i int) {
			fmt.Printf("%v\n", i)
			ch <- i
		}(i)
	}

	for i := 0; i < 10; i++ {
		<-ch
	}

}

func tickTimer() {
	// run at fixed interval
	for now := range time.Tick(2 * time.Second) {
		fmt.Println(now)
	}
}

func waitAct() {
	timer := time.AfterFunc(3*time.Second, func() {
		fmt.Println("work in timer")
	})
	defer timer.Stop()
	fmt.Println("timer started")
	time.Sleep(5 * time.Second)
	fmt.Println("exit")
}

func main() {
	// async_chan()
	// timeroutTimer()
	// cancelTimer()
	// tickTimer()
	waitAct()
}