queues

README

Queues

A simple sync.WaitGroup like queue and goroutine execution controller.

Features

• Limit maximum goroutine execution/count.
• Wait for all the goroutines to finish.
• Run goroutines like a queue batch.

Import

import "github.com/hsblhsn/queues"

Example

🔗 Go Playground: Limit maximum goroutine counts to 3.

package main

import (
	"fmt"
	"time"

	"github.com/hsblhsn/queues"
)

func main() {
	q := queues.New(3)
	for i := 0; i < 30; i++ {
		q.Add(1)
		go func(n int) {
			defer q.Done()
			time.Sleep(time.Second)
			fmt.Println(n)
		}(i)
	}
	q.Wait()
}

🔗 Go Playground: Batched queue for async jobs.

package main

import (
	"fmt"
	"time"

	"github.com/hsblhsn/queues"
)

func main() {
	urls := []string{
		"https://google.com",
		"https://github.com",
		"https://twitter.com",
		"https://facebook.com",
		"https://youtube.com",
	}
	q := queues.New(2)
	for _, v := range urls {
		q.Add(1)
		go crawl(q, v)
	}
	q.Wait()
}

func crawl(q *queues.Q, url string) {
	defer q.Done()
	fmt.Println("Crawling: ", url)
	time.Sleep(time.Second)
}

Documentation

Index

• type Q
  • func New(max uint) *Q
  • func (q *Q) Add(delta int)
  • func (q *Q) Done()
  • func (q *Q) Exit()
  • func (q *Q) Wait()

Types

type Q

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

Q is a queue. Uses Go Channel and sync.WaitGroup under the hood.

func New

func New(max uint) *Q

New returns a new queue with the given max size. No more than max size items can be added to the queue. It uses Golang's channel under the hood. Think this function as make(chan int, maxSize). So, if you set the max size to 0, it will not work as a queue or buffer.

func (*Q) Add

func (q *Q) Add(delta int)

Add adds an item to the queue. It uses wg.Add(n) to keep track of the number of items in the queue.

func (*Q) Done

func (q *Q) Done()

Done removes an item from the queue. It uses wg.Done() to keep track of the number of items in the queue.

func (*Q) Exit

func (q *Q) Exit()

Exit calls q.Done() first then calls runtime.Goexit(). If called inside a goroutine, the goroutine will exit immediately. See https://golang.org/pkg/runtime/#Goexit for the documentation.

func (*Q) Wait

func (q *Q) Wait()

Wait for the queue to be empty. It uses wg.Wait() to wait for the queue to be empty.