Laravel Cloud Pub/Sub.

Why?

Build a scalable Laravel apps using event-driven microservices architecture (Pub/Sub), this tool adds the ability for your Laravel applications to communicate with each other using Google Cloud Pub/Sub.

Define your architecture.

First of all, you need to create subscriptions and topics in Google Cloud Platform, or you can use the cli.

• Quickstart using the gcloud command-line tool

Installation.

• composer require gdg-tangier/cloud-pubsub

Configuration.

• config/queue.php

You can define multiple subscribers (queue connections) config in config/queue.php, the app can subscribe to multiple subscriptions.

Example.

'pubsub' => [
      'driver' => 'pubsub',
      'queue'  => env('SUBSCRIPTION'),
      'credentials' => [
          'keyFilePath' => storage_path(env('PUBSUB_CLIENT_KEY')), // credentials file path '.json'
          'projectId'   => env('GCP_PROJECT_ID'),
      ],
  ],

• config/pubsub.php

Here where you can define your subscriptions jobs, events and topics mappings.

Example.

<?php

return [
    /*
     * GCP Credentials.
     */
    'credentials' => [
        'keyFilePath' => storage_path(env('PUBSUB_CLIENT_KEY', 'client')),
        'projectId'   => env('GCP_PROJECT_ID'),
    ],

    /*
     * Here where you map events name with Google Pub/Sub topics.
     *
     * Means, map each event name to specific Google Pub/Sub topic.
     */
    'events'      => [
        'event_name' => '__YOUR_TOPIC_NAME__',
    ],

    /*
     * Here where you can tie the subscription classes (jobs) to topics.
     *
     * Means, map each subscription job to a specific Google pubsub topic.
     * The subscription job is responsible for handling the incoming data
     * from a Google Pub/Sub topic.
     */
    'subscriptions'        => [
        \App\PubSub\DummyJob::class => '__YOUR_TOPIC_NAME__',
    ],
];

Create subscription class.

• php artisan pubsub:make-subscriber <Name>

A subscription class will be created at app/Subscribers

Example.

<?php

namespace App\Subscribers;

use GDGTangier\PubSub\Subscriber\SubscriberJob;
use GDGTangier\PubSub\Subscriber\Traits\JobHandler;

class UserUpdated
{
    use JobHandler;

    /**
     * @var mixed
     */
    public $payload;

    /**
     * @var \GDGTangier\PubSub\Subscriber\SubscriberJob
     */
    public $job;

    /**
     * UserUpdated constructor.
     *
     * @param \GDGTangier\PubSub\Subscriber\SubscriberJob $job
     * @param $payload
     */
    public function __construct(SubscriberJob $job, $payload)
    {
        $this->job = $job;
        $this->payload = $payload;
    }

    /**
     * Execute the job.
     *
     * @return void
     */
    public function handle()
    {
        // 
    }
}

Publishing data to the cloud.

• Using facade.

use GDGTangier\PubSub\Publisher\Facades\PublisherFacade;

PublisherFacade::publish('MyData', 'event_name');

• Using service container.

$publisher = app('gcloud.publisher.connection');

$publisher->publish('MyData', 'event_name');

• Using artisan command.

php artisan pubsub:publish <message> <event>

Subscriptions worker.

• php artisan pubsub:subscribe <connection>

Or alternatively you can run php artisan queue:work <connection>

Note: To keep the queue:subscribe process running permanently in the background, you should use a process monitor such as supervisor to ensure that the queue worker does not stop running.

Using GCP Pub/Sub emulator.

You need to install GCP command line tool and Setup Topics/Subscriptions

To use the emulator:

1. Go to the AppServiceProvider@register and add PubSub::useEmulatorCredentials()

2. Export the pubsub emulator host export PUBSUB_EMULATOR_HOST=localhost:8085

3. Run the emulator, php artisan pubsub:emulator

Testing.

You need to install GCP command line tool.

1. Run the pubsub emulator./emulator.sh
2. Export the pubsub emulator host export PUBSUB_EMULATOR_HOST=localhost:8085
3. Run phpunit