This demonstrates usage of timer in go. Both one-shot timer and periodic timer. In the periodic timer example, goroutine and select are used.

test_periodic_timer.go

package main

import (
    "fmt"
    "time"
)

// The timeout handler.
func ontimeout(t time.Time) {
    fmt.Println("[timeout] ", t)
}

// Schedule callback every interval milliseconds.
func periodic_timer(interval time.Duration,
                    callback func(time.Time)) {
    var timer *time.Timer
    for {
        // Creates a new Timer that will send the current time on
        // its channel C after (at least) the specified duration.
        timer = time.NewTimer(interval * time.Millisecond)

        // Wait for timeout.
        select {
            case t := <-timer.C:
                ontimeout(t)
        }
    }
}

func main() {
    // Run periodic_timer in main goroutine
    // periodic_timer(1000, ontimeout)

    // Run periodic_timer in another goroutine
    go periodic_timer(1000, ontimeout)  // [1]
    for {
        // the main goroutine has to sleep so that [1] could run
        time.Sleep(5000 * time.Millisecond)
    }
}

test_timer.go

package main

import (
    "log"
    "time"
)

func ontimeout() {
    log.Println("timeout is occurred")
}

func main() {
    for {
        // AfterFunc waits for the duration to elapse and then calls f
        // in its own goroutine. It returns a Timer that can be used to
        // cancel the call using its Stop method. 
        timer := time.AfterFunc(1000 * time.Millisecond, ontimeout)
        log.Println("timer installed: ", timer)
        time.Sleep(5000 * time.Millisecond)
    }
}