go-eventbus

Event bus for Go, leveraging ants for worker pool management.

Installation

$ go get -u github.com/pilagod/go-eventbus

Usage

You should import eventbus module under go-eventbus:

import "github.com/pilagod/go-eventbus/eventbus"

Initialization

Event bus must be setup beforehead:

var workerPoolSize = 4

func main() {
    // ...

    eb, err := eventbus.Setup(workerPoolSize)
    if err != nil {
        panic(err.Error())
    }
    // don't forget to release workers
    defer eb.Release()

    // ...
}

Event Subscriber

type Event struct {
    Message string
}

type EventHandler struct {}

func (h *EventHandler) Handle(event eventbus.Event) error {
    e, ok := event.(Event)
    if !ok {
        // just ignore this event
        return nil
    }
    fmt.Println(e.Message)
    return nil
}

es := eventbus.GetEventSubscriber() // GetEventSubscriber will panic if event bus hasn't setup

// Subscribe handler to specific event
es.Subscribe(Event{}, &EventHandler{})

// Subscribe handler to all events
es.SubscribeAll(&EventHandler{})

You can hook common handler logic by Use method:

func LogHandler(h eventbus.EventHandler) eventbus.EventHandler {
    return &logHandler{h}
}

type logHandler struct {
    eventbus.EventHandler
}

func (h *logHandler) Handle(event eventbus.Event) error {
    fmt.Println("Log event: %v", event)
    return h.EventHandler.Handle(event)
}

es := eventbus.GetEventSubscriber()

// Hook logger for handler
es.Use(LogHandler)

Event Publisher

type Event struct {
    Message string
}

ep := eventbus.GetEventPublisher() // GetEventPublisher will panic if event bus hasn't setup

// Publish specific event
e := Event{
    Message: "Hello World",
}
ep.Publish(e)

// Publish multiple events
es := []eventbus.Event{
   Event{Message: "A"}, 
   Event{Message: "B"}, 
   Event{Message: "C"}, 
}
ep.Publish(es...)

License

© Cyan Ho (pilagod), 2021-NOW

Released under the MIT License