ove*_*nge -3 design-patterns go publish-subscribe
根据这个答案,
消息总线是一种消息传递基础结构,允许不同的系统通过一组共享的接口(消息总线)进行通信。
以下是创建消息中心以将发布者与多个订阅者进行通信所启动的createHub()
功能和Run()
方法main()
:
type PubHub struct {
subscribers map[*subscriptionmediator.HandlerSubscription]struct{}
Register chan *subscriptionmediator.HandlerSubscription
Unregister chan *subscriptionmediator.HandlerSubscription
Broadcast chan *events.Env
}
func createHub() *PubHub {
return &PubHub{
subscribers: map[*subscriptionmediator.HandlerSubscription]struct{}{},
Register: make(chan *subscriptionmediator.HandlerSubscription),
Unregister: make(chan *subscriptionmediator.HandlerSubscription),
Broadcast: make(chan *events.Envelope),
}
}
func (h *PubHub) Run() {
for {
select {
case subscriber := <-h.Register:
h.subscribers[subscriber] = struct{}{}
case subscriber := <-h.Unregister:
if _, ok := h.subscribers[subscriber]; ok {
delete(h.subscribers, subscriber)
}
case message := <-h.Broadcast:
for subscriber := range h.subscribers {
subscriber.DataChannel <- message
}
}
}
}
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每个订阅者注册的地方,如下图:
subscription := &subscriptionmediator.HandlerSubscription{
conn,
make(chan *events.Envelope),
}
hub.Register <- subscription
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DataChannel
用于发布者和多个订阅者之间的通信
type HandlerSubscription struct {
ConnInstance *websocket.Conn
DataChannel chan *events.Envelope
}
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1) 是否可以将上述代码视为遵循基于消息总线的 pub-sub 模式?
2)如何避免一个订阅者阻止所有订阅者在频道上发信号? subscriber.DataChannel <- message