zmqpubsub is a simple Go pubsub implementation on top of ZeroMQ.

It abstracts the underlying ZeroMQ machinery to provide a Go-friendly API for the publish-subscribe messaging pattern.

go get -tags zmq_3_x github.com/hpcloud/zmqpubsub

First setup a broker:

var Broker zmqpubsub.Broker

func init() {
	Broker.PubAddr = "tcp://127.0.0.1:4000"
	Broker.SubAddr = "tcp://127.0.0.1:4001"
	Broker.BufferSize = 100
}

func main() {
    ...
    Broker.MustRun()
}

The broker specifies the addresses to which publishers/subscribers will connect to/from.

Subscription messages are sent in a Go channel. Thanks to Tomb, subscriptions can be stopped at any time by calling Stop.

sub := Broker.Subscribe("")
defer sub.Stop()

for msg := range sub.Ch {
    fmt.Printf("%s => %s\n", msg.Key, msg.Value)
}

The publisher part is equivalently simple. It should be noted however that as publishers are not thread-safe they must be managed from the same goroutine that created them.

pub := Broker.NewPublisherMust()
defer pub.Stop()

pub.MustPublish("key", "hello world")
pub.MustPublish("key", "hello universe")

To run the provided example,

go run -tags zmq_3_x example/pubsub.go