eventual

eventual

-- import "github.com/fzerorubigd/eventual"

Package eventual is a simple event dispatcher for golang base on channels. The goal is to pass data around, without depending to any package except for this one.

There is some definition :

• Mandatory means publish is not finished unless all subscribers receive the message, in this case, the receiver must always read the channel. TODO : a way to unsub
• Exclusive means there is only and only one receiver for a topic is available

Sample code

package main

import "github.com/fzerorubigd/eventual"

func main() {
    e := &eventual.Eventual{}
    // Create a no mandatory, no exclusive topic
    t ,_ := e.Register("the.topic.name", false, false)
    c1 := t.Sub()

    // In any other part of code, even in another package you can create
    // an exactly same topic with exactly same parameter
    t ,_ := e.Register("the.topic.name", false, false)
    t.Pub(SomeIEventStructure{}) // No there is a data in c1, but if there is no reader the data is lost
}

TODO

• Support for buffer size (aka pre fetch)

• Support for reply back

Usage

type Event

type Event interface {
	Publisher
	Subscriber

	// GetTopic return the current topic
	GetTopic() string
	// IsMandatory return if this event is mandatory or not , mandatory means
	IsMandatory() bool
	// IsExclusive return if this event is exclusive and there is only one subscriber
	// is allowed
	IsExclusive() bool
}

Event is the actual event, must register to get one of this.

type Eventual

type Eventual interface {
	Register(topic string, mandatory, exclusive bool) (Event, error)
}

Eventual is an event bus

func New

func New() Eventual

New return an eventual structure

type IEvent

type IEvent interface {
	// Data is the event data that publisherdecide the type of it
	Data() interface{}
}

IEvent is an interface to handle one instance of an event in system. each IEvent must contain the topic and data that passed to this event

type Publisher

type Publisher interface {
	// Pub is for publish an event. it's panic prof
	Pub(IEvent)
}

Publisher is an interface for publishing event in a system

type Subscriber

type Subscriber interface {
	// Sub is for getting an channel to read the events from it.
	// if the event is exclusive, and there is a subscriber, then
	// it panic.
	Sub() <-chan IEvent
}

Subscriber is an interface to handle subscribers