two ways to call a function every 2 seconds

golang-nuts.go

package main

import (
	"fmt"
	"time"
)

// Suggestions from golang-nuts
// http://play.golang.org/p/Ctg3_AQisl

func doEvery(d time.Duration, f func(time.Time)) {
	for x := range time.Tick(d) {
		f(x)
	}
}

func helloworld(t time.Time) {
	fmt.Printf("%v: Hello, World!\n", t)
}

func main() {
	doEvery(20*time.Millisecond, helloworld)
}

polling.go

package main

import (
  "fmt"
  "time"
  "net/http"
)

func doSomething(s string) {
  fmt.Println("doing something", s)
}

func startPolling1() {
  for {
    time.Sleep(2 * time.Second)
    go doSomething("from polling 1")
  }
}

func startPolling2() {
  for {
    <-time.After(2 * time.Second)
    go doSomething("from polling 2")
  }
}

func handler(w http.ResponseWriter, r *http.Request) {
  fmt.Fprintf(w, "Hi there, I love %s!", r.URL.Path[1:])
}

func main() {
  go startPolling1()
  go startPolling2()

  http.HandleFunc("/", handler)
  http.ListenAndServe(":8080", nil)
}

You just saved me, thanks for posting this!

Wow, the way of keeping service running using HandleFunc & ListenAndServe is very clever. I've never thought about that.

Nice, for what Im looking for

Thank you for posting this ;)
And thank you search engines for indexing this post :D

why not just using something like select{} or waitgroup?

Thank you for posting...

Great.

doEvery(20*time.Millisecond, helloworld)

calls helloworld every 0.02 seconds, not every 2 seconds

ty, still good solution for 2020, haha

How to stop the polling?

@IgorDePaula take a look at this playground:
https://play.golang.org/p/l_9R0d71iIJ
I've altered the time.Tick solution to use a select together with Context.

@q42jaap Thank you

thanks <3

Thank you !

Nice