go-eventlistener-example

README

go-eventlistener-example

Go Lang REST API example with event listeners

This project is a demo of a very basic implementation of Observer Pattern with one event publisher and many listeners.

Each commit in master branch represent development progressions from a basic rest api server (before implementing event listeners) to the very end of the commit (after implements event listeners). You can compare the difference between each commits.

Running

To run the example:

go run .

User Event

In this source code, we have one event publisher UserEvent which implement ApplicationEvent interface.

Also we have two listeners:

• 1st listening on UserCreated channel
• 2nd listening on SlackNotifier channel

All channel accept arbitraty interface{} as object that we can pass everytime an event is published.

Example below showing 2 listener subscibed to user_created event:

var userEvent *events.UserEvent = &events.UserEvent{}
userEvent.Subscribe("user_created", listeners.UserCreated)
userEvent.Subscribe("user_created", listeners.SlackNotifier)

Then, whenever user_created event is published, it will be broadcasted to all its listeners

userEvent.Publish("user_created", user)

in the code above, the user is the arbitraty object passed to all the listeners, so then they can do further logic to it.

Example code showing a listener doing its job:

var SlackNotifier = make(chan interface{})

func init() {
	go func() {
		for {
			user := <-SlackNotifier
			fmt.Println("Notify about user to slack ", user)
		}
	}()
}