PubSub library for Brickchain

Abstraction layer and helper for PubSub systems
The PubSubInterface interface has three methods:

• Publish(topic string, data string) error, Publish a message to a topic
• Subscribe(topic string) (*Subscriber, error), Start a subscriber on a topic and return a Subscriber
• DeleteTopic(topic string) error, Clean up a topic

The Subscriber interface has two methods:

• Pull(timeout time.Duration) (string, int), Get a message. The integer returned is 0 for success or 1 for timeout
• Stop(timeout time.Duration), Stop the subscriber

Publisher using Google PubSub

import (
    "github.com/Brickchain/go-pubsub.v1"
)

func Publish(msg string) {
	p, err := pubsub.NewGCloudPubSub("project-id", "/path/to/credentials.json")
	if err != nil {
		panic(err)
	}
	
	err = p.Publish("some-topic", "some message to publish")
	if err != nil {
	    panic(err)
	}
}

Subscriber using Google PubSub

import (
    "fmt"
    "github.com/Brickchain/go-pubsub.v1"
)

func Subscriber() {
    	p, err := pubsub.NewGCloudPubSub("project-id", "/path/to/credentials.json")
    	if err != nil {
    		panic(err)
    	}
    	
        sub, err := p.Subscribe("subscriber_group_name", "some-topic")
        if err != nil {
            t.Error(err)
        }
        
        for i := 0; i < 10; i++ {
            msg, ok := sub.Pull(10)
            if ok == TIMEOUT {
                fmt.Println("Pull timed out")
            }
            fmt.Println("Received message:", msg)
        }
}

Start the Google Cloud PubSub emulator

gcloud beta emulators pubsub start --host-port=localhost:9111

Then run export PUBSUB_EMULATOR_HOST=localhost:9111 in the shell where you will run the tests.