Golang message broker

broker.go

package protocol

import (
	"fmt"
	"log"
)

// pubsub
type Broker struct {
	Send map[string]*chan *Message
}

func (broker *Broker) Bind(key string, channel *chan *Message) {
	broker.Send[key] = channel
}

func (broker *Broker) Unbind(key string) {
	delete(broker.Send, key)
}

// route
type Notify struct {
	All    bool
	None   bool
	One    string
	Only   []string
	Except []string
}

func (n *Notify) String() string {
	s := "[NOTIFY]"
	if n.All {
		s += " all"
	}
	if n.None {
		s += " mone"
	}
	if n.One != "" {
		s += fmt.Sprintf(" one: %v", n.One)
	}
	if len(n.Except) != 0 {
		s += fmt.Sprintf(" except: %v", n.Except)
	}
	if len(n.Only) != 0 {
		s += fmt.Sprintf(" only: %v", n.Only)
	}
	return s
}

func NewBroker() *Broker {
	return &Broker{
		Send: map[string]*chan *Message{},
	}
}

func (broker *Broker) Dispatch(msg *Message, n *Notify) {
	log.Printf("%s | %s\n", n.String(), msg.String())

	if n.None {
		return
	}

	if n.One != "" {
		*broker.Send[n.One] <- msg
		return
	}

	for key, send := range broker.Send {
		if !n.All {
			var skip bool

			if len(n.Only) != 0 {
				skip = true
				for _, Only := range n.Only {
					if Only == key {
						skip = false
						break
					}
				}
			}
			if len(n.Except) != 0 {
				skip = false
				for _, Except := range n.Except {
					if Except == key {
						skip = true
						break
					}
				}
			}
			if skip {
				continue
			}
		}
		*send <- msg
	}
}