Timers and Tickers

Introduction

This lab is about using tickers in Golang. Tickers are used when you want to do something repeatedly at regular intervals.

Skills Graph

Timers and Tickers

In this lab, you need to create a ticker that ticks every 500ms until we stop it. You will use a channel to await the values as they arrive.

• Use the time package to create a ticker.
• Use a channel to await the values as they arrive.
• Use the select statement to receive values from the channel.
• Stop the ticker after 1600ms.

## When we run this program the ticker should tick 3 times
## before we stop it.
$ go run tickers.go
Tick at 2012-09-23 11:29:56.487625 -0700 PDT
Tick at 2012-09-23 11:29:56.988063 -0700 PDT
Tick at 2012-09-23 11:29:57.488076 -0700 PDT
Ticker stopped

There is the full code below:

// [Timers](timers) are for when you want to do
// something once in the future - _tickers_ are for when
// you want to do something repeatedly at regular
// intervals. Here's an example of a ticker that ticks
// periodically until we stop it.

package main

import (
	"fmt"
	"time"
)

func main() {

	// Tickers use a similar mechanism to timers: a
	// channel that is sent values. Here we'll use the
	// `select` builtin on the channel to await the
	// values as they arrive every 500ms.
	ticker := time.NewTicker(500 * time.Millisecond)
	done := make(chan bool)

	go func() {
		for {
			select {
			case <-done:
				return
			case t := <-ticker.C:
				fmt.Println("Tick at", t)
			}
		}
	}()

	// Tickers can be stopped like timers. Once a ticker
	// is stopped it won't receive any more values on its
	// channel. We'll stop ours after 1600ms.
	time.Sleep(1600 * time.Millisecond)
	ticker.Stop()
	done <- true
	fmt.Println("Ticker stopped")
}

Summary

In this lab, you learned how to use tickers in Golang. You created a ticker that ticks every 500ms until we stop it, used a channel to await the values as they arrive, and stopped the ticker after 1600ms.