throttle-goroutine.go

package main

import (
	"fmt"
	"sync"
	"time"
)

type Task struct {
	id int
}

func main() {
	tasks := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

	jobs := make(chan Task, 3)
	var wg sync.WaitGroup
	wg.Add(len(tasks))

	for _, e := range []int{1, 2, 3} {
		worker := func(id int) {
			for t := range jobs {
				defer wg.Done()
				d := time.Duration(500) * time.Millisecond
				fmt.Printf("worker[%v] task[%v] %v\n", id, t.id, d)
				time.Sleep(d)
			}
		}
		go worker(e)
	}

	for _, e := range tasks {
		jobs <- Task{e}
	}
	close(jobs)

	wg.Wait()
}