EventBus for Golang

Description

This is a simple implementation of an event bus in golang. Actually support follwing pattern:

• publish/subscribe
• request/response

Get Started

To start use eventbus in your project, you can run the following command.

go get github.com/stanipetrosyan/go-eventbus

And import

import (
	goeventbus "github.com/stanipetrosyan/go-eventbus"
)

Publish/Subscribe

Simple example of publish/subscribe pattern.

eventbus = goeventbus.NewEventBus()

address := "topic"
options := goeventbus.NewMessageHeadersBuilder().SetHeader("header", "value").Build()
message := goeventbus.NewMessageBuilder().SetPayload("Hi Topic").SetHeaders(options).Build()

eventbus.Channel(address).Subscriber().Listen(func(dc goeventbus.Context) {
	fmt.Printf("Message %s\n", dc.Result().Data)
})

eventbus.Channel(address).Publisher().Publish(message)

Request/Response

Simple example of request/response pattern.

eventbus = goeventbus.NewEventBus()

address := "topic"
message := goeventbus.NewMessageBuilder().SetPayload("Hi Topic").Build()

eventbus.Channel(address).Subscriber().Listen(func(context goeventbus.Context) {
	fmt.Printf("Message %s\n", context.Result().Extract())
	context.Reply("Hello from subscriber")
})

eventbus.Channel(address).Publisher().Request(message, func(context goeventbus.Context) {
	fmt.Printf("Message %s\n", context.Result().Extract())
})

Message

For publishing, you need to create a Message object using this method.

message := goeventbus.NewMessageBuilder().SetPayload("Hi Topic").SetHeaders(options).Build()

Each message can have some options:

options := goeventbus.NewMessageHeadersBuilder().SetHeader("header", "value").Build()
message := goeventbus.NewMessageBuilder().setHeaders(options).Build()

eventBus.Channel("address").Publisher().Publish(message)

Processor

A processor works like a middleware, in fact forwards messages only if the predicate is satisfied. The method accepts a function with message and return must return a boolean.

eventbus.Channel("topic1").Processor(func(message goeventbus.Message) bool {
	return message.Options.Headers().Contains("header")
})

Network Bus

A Network bus create a tcp connection between different services.

NetworkBus is a wrapper of local eventbus.

A simple server/client example is in examples/networkbus directory.