Request worker pool written in Go.

pool.go

package pool

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

var (
	MaxPoolQueue  = 100
	MaxPoolWorker = 10
)

type Pool struct {
	wg *sync.WaitGroup

	queue  chan *http.Request
	errors chan error
}

func NewPool() *Pool {
	return &Pool{
		wg: &sync.WaitGroup{},

		queue:  make(chan *http.Request, MaxPoolQueue),
		errors: make(chan error),
	}
}

func (p *Pool) Add(r *http.Request) {
	p.wg.Add(1)

	p.queue <- r
}

func (p *Pool) Run() error {
	for i := 0; i < MaxPoolWorker; i++ {
		go p.doWork()
	}

	for {
		select {
		case err := <-p.errors:
			return err
		default:
			p.wg.Wait()
		}
	}

	return nil
}

func (p *Pool) doWork() {
	for r := range p.queue {
		fmt.Printf("Request to %s\n", r.Host)

		p.wg.Done()

		_, err := http.DefaultClient.Do(r)

		if err != nil {
			p.errors <- err
		}
	}
}