PubSub

pubsub.go

package main

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

type PubSub struct {
	mux sync.RWMutex
	sub map[string][]chan string
}

func NewPubSub() *PubSub {
	s := make(map[string][]chan string, 0)
	ps := &PubSub{
		sub: s,
	}
	return ps
}

func (ps *PubSub) Subscribe(topic string) chan string {
	ps.mux.Lock()
	defer ps.mux.Unlock()

	ch := make(chan string, 1)
	ps.sub[topic] = append(ps.sub[topic], ch)
	return ch
}

func (ps *PubSub) Publish(topic string, message string) {
	for _, ch := range ps.sub[topic] {
		ch <- message
	}
}

func main() {
	ps := NewPubSub()
	ch1 := ps.Subscribe("test")
	ch2 := ps.Subscribe("test")

	go func() {
		for {
			select {
			case msg := <-ch1:
				fmt.Println(msg + " to ch1")
			case msg := <-ch2:
				fmt.Println(msg + " to ch2")
			}
		}
	}()

	for {
		ps.Publish("test", "sample")
		time.Sleep(time.Second * 1)
	}
}