Worker Pool example

workerpool.go

package main

import (
	"fmt"
	"log"
	"math/rand"
	"sync"
	"time"
)

var settings = struct {
	workers int
}{
	workers: 10,
}

func main() {
	jobNum := 100

	// setup channel an wg
	jobChan := make(chan string, jobNum)
	wg := &sync.WaitGroup{}

	// set up jobs: push into channel to queue them to be processed
	for i := 0; i < jobNum; i++ {
		wg.Add(1)
		jobChan <- fmt.Sprintf("job number %d", i)
	}
	close(jobChan)

	// set up X number workers to process jobs
	for i := 0; i < settings.workers; i++ {
		go func(wg *sync.WaitGroup, workerNum int, jc chan string) {
			log.Println("worker starting:", workerNum)
			for job := range jc {
				log.Printf("worker:%d processing job:%v\n", workerNum, job)
				time.Sleep(time.Duration(rand.Int63n(500)) * time.Millisecond)
				wg.Done()
			}

			log.Println("worker stopping:", workerNum)
		}(wg, i+1, jobChan)
	}

	// wait for them to be finished
	wg.Wait()
	log.Println("done")
}