periodic

Documentation

Overview

Package periodic provides a way to execute a given function periodically at a specified time interval.

It allows for the configuration of a maximum random jitter time between each function call and a timeout applied to each function call via Context. The jitter is useful for avoiding the Thundering herd problem (https://en.wikipedia.org/wiki/Thundering_herd_problem).

Index

• type Periodic
  • func New(interval time.Duration, jitter time.Duration, timeout time.Duration, ...) (*Periodic, error)
  • func (p *Periodic) Start(ctx context.Context)
  • func (p *Periodic) Stop()
• type TaskFn

Examples

• New

Types

type Periodic

type Periodic struct {
	// contains filtered or unexported fields
}

Periodic instance.

func New

func New(interval time.Duration, jitter time.Duration, timeout time.Duration, task TaskFn) (*Periodic, error)

New creates a new Periodic instance. The jitter parameter is the maximum random Jitter time between each function call. This is useful to avoid the Thundering herd problem (https://en.wikipedia.org/wiki/Thundering_herd_problem).

Example

package main

import (
	"context"
	"fmt"
	"log"
	"time"

	"github.com/Vonage/gosrvlib/pkg/periodic"
)

func main() {
	count := make(chan int, 1)

	count <- 0

	// example task to execute periodically
	task := func(_ context.Context) {
		v := <-count
		count <- (v + 1)
	}

	interval := 20 * time.Millisecond
	jitter := 2 * time.Millisecond
	timeout := 2 * time.Millisecond

	// create a new periodic job
	p, err := periodic.New(interval, jitter, timeout, task)
	if err != nil {
		close(count)
		log.Fatal(err)
	}

	// start the periodic job
	p.Start(context.TODO())

	// wait for 3 times the interval
	wait := 3 * interval
	time.Sleep(wait)

	// stop the periodic job
	p.Stop()

	fmt.Println(<-count)

	close(count)

}

Output:

3

func (*Periodic) Start

func (p *Periodic) Start(ctx context.Context)

Start the periodic execution.

func (*Periodic) Stop

func (p *Periodic) Stop()

Stop the periodic execution. It may block until the last running function returns.

type TaskFn

type TaskFn func(context.Context)

TaskFn is the type of function to be periodically executed.