gobus

README

PubSub Event bus for Go

Package go-bus is a thread-safe, zero-alloc, pub-sub event bus for embebbed go apps and microservices.

Install

go get github.com/zerjioang/go-bus

TL;DR

func TestExampleCalculationBus(t *testing.T) {
	//define a global bus instance
	bus := mutex.NewBus()

	//register our subscriber: the calculation engine
	bus.Subscribe("calc", func(message gobus.EventMessage) {
		println("new calculation request arrived")
		a := message.Get("a").(int)
		b := message.Get("b").(int)
		println("received a = ", a)
		println("received b = ", b)
		println("the sum is", a+b)
	})

	//register our data publisher
	bus.Send("calc", gobus.EventPayload{
		"a": 5,
		"b": 10,
	})

	bus.Send("calc", gobus.EventPayload{
		"a": 8,
		"b": 12,
	})

	bus.Shutdown()
}

new calculation request arrived
new calculation request arrived
received a =  5
received b =  10
received a =  8
received b =  12
the sum is 15
the sum is 20

Benchmarking

Always do benchmarking with your own data. Here are mine:

For mutex based version

BenchmarkEventBus/instantiation-4                     2000000000	         0.42 ns/op	2394.34 MB/s	       0 B/op	       0 allocs/op
BenchmarkEventBus/instantiation-ptr-                  2000000000	         0.43 ns/op	2310.56 MB/s	       0 B/op	       0 allocs/op
BenchmarkEventBus/str-to-uint32-4                       50000000	        37.6 ns/op	  26.56 MB/s	       0 B/op	       0 allocs/op
BenchmarkEventBus/subscribe-4                            5000000	       274 ns/op	   3.64 MB/s	      43 B/op	       0 allocs/op
BenchmarkEventBus/subscribe-invalid-no-name-4          500000000	         3.38 ns/op	 295.51 MB/s	       0 B/op	       0 allocs/op
BenchmarkEventBus/subscribe-invalid-no-listener-4      300000000	         4.20 ns/op	 238.03 MB/s	       0 B/op	       0 allocs/op
BenchmarkEventBus/publish-no-subscriber-4                3000000	       468 ns/op	   2.13 MB/s	       0 B/op	       0 allocs/op
BenchmarkEventBus/publish-with-subscriber-4              3000000	       476 ns/op	   2.10 MB/s	       0 B/op	       0 allocs/op
BenchmarkEventBus/pub-sub-4                               100000	     79957 ns/op	   0.01 MB/s	      48 B/op	       0 allocs/op
PASS

Special thanks to http://ernestmicklei.com/2014/11/guava-like-eventbus-for-go/ for it's original approach

License

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Uses GPL license described below

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Documentation

Index

• type EventListener
• type EventMessage
  • func NewEventMessage(id string, data map[string]interface{}) EventMessage
  • func (m *EventMessage) Get(key string) interface{}
• type EventPayload

Types

type EventListener

type EventListener func(EventMessage)

EventListener is the signature of functions that can handle an EventMessage.

type EventMessage

type EventMessage struct {
	// contains filtered or unexported fields
}

EventMessage is send on the bus to all subscribed listeners

func NewEventMessage

func NewEventMessage(id string, data map[string]interface{}) EventMessage

func (*EventMessage) Get

func (m *EventMessage) Get(key string) interface{}

type EventPayload

type EventPayload map[string]interface{}

EventPayload represents the context of an event, a simple key-value map.