Event Bus NSQ

• A tiny wrapper around go-nsq topic and channel.
• Protect nsq calls with gobreaker.

Installation

go get -u github.com/rafaeljesus/nsq-event-bus

Usage

The nsq-event-bus package exposes a interface for emitting and listening events.

Emitter

import "github.com/rafaeljesus/nsq-event-bus"

topic := "events"
emitter, err := bus.NewEmitter(bus.EmitterConfig{
  Address: "localhost:4150",
  MaxInFlight: 25,
})

e := event{}
if err = emitter.Emit(topic, &e); err != nil {
  // handle failure to emit message
}

// emitting messages on a async fashion
if err = emitter.EmitAsync(topic, &e); err != nil {
  // handle failure to emit message
}

Listener

import "github.com/rafaeljesus/nsq-event-bus"

if err = bus.On(bus.ListenerConfig{
  Topic:              "topic",
  Channel:            "test_on",
  HandlerFunc:        handler,
  HandlerConcurrency: 4,
}); err != nil {
  // handle failure to listen a message
}

func handler(message *Message) (reply interface{}, err error) {
  e := event{}
  if err = message.DecodePayload(&e); err != nil {
    message.Finish()
    return
  }

  if message.Attempts > MAX_DELIVERY_ATTEMPTS {
    message.Finish()
    return
  }

  err, _ = doWork(&e)
  if err != nil {
    message.Requeue(BACKOFF_TIME)
    return
  }

  message.Finish()
  return
}

Request (Request/Reply)

import "github.com/rafaeljesus/nsq-event-bus"

topic := "user_signup"
emitter, err = bus.NewEmitter(bus.EmitterConfig{})

e := event{Login: "rafa", Password: "ilhabela_is_the_place"}
if err = bus.Request(topic, &e, handler); err != nil {
  // handle failure to listen a message
}

func handler(message *Message) (reply interface{}, err error) {
  e := event{}
  if err = message.DecodePayload(&e); err != nil {
    message.Finish()
    return
  }

  reply = &Reply{}
  message.Finish()
  return
}

Contributing

• Fork it
• Create your feature branch (git checkout -b my-new-feature)
• Commit your changes (git commit -am 'Add some feature')
• Push to the branch (git push origin my-new-feature)
• Create new Pull Request

Badges

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GitHub @rafaeljesus  ·  Medium @_jesus_rafael  ·  Twitter @_jesus_rafael