Example for multiple producers and consumers for a channel

channel_concurrency.go

package main

import (
	"fmt"
	"sync"
)

func main() {
	eventBus := make(chan string)

	wg := &sync.WaitGroup{}
	wg.Add(20)
	go eventProducers(eventBus, wg)

	for i := 1; i <= 15; i++ {
		go func(eventBus chan string, id int, wg *sync.WaitGroup) {
			select {
			case msg := <-eventBus:
				fmt.Printf("id: %v, event: %v\n", id, msg)
			}
			wg.Done()
		}(eventBus, i, wg)
	}
	wg.Wait()
	close(eventBus)
	fmt.Println("exiting")
}

func eventProducers(eventBus chan string, wg *sync.WaitGroup) {
	for i := 1; i <= 5; i++ {
		go func(wg *sync.WaitGroup, eventBus chan string, id int) {
			for j := 1; j <= 3; j++ {
				eventBus <- fmt.Sprintf("%v.%v", id, j)
			}
			wg.Done()
		}(wg, eventBus, i)
	}
}