Event Orchestration with Laravel’s Bus Chain

In the ever-evolving landscape of Laravel, developers are continually discovering new and powerful features that streamline their workflows.

One such gem are the Bus Chain, a robust mechanism for chaining events in order to orchestrate the jobs execution.

In this blog post, we’ll delve into the concept of the Bus Chain in Laravel and explore how it can be a game-changer for handling events seamlessly.

Understanding Laravel’s Bus Chain

The Bus Chain in Laravel provides an elegant solution for executing multiple events in a specific order, creating a well-defined sequence of actions.

This is particularly useful when you need to orchestrate complex workflows or ensure that events are handled in a specific order.

Setting Up the Bus Chain

To start leveraging the Bus Chain, first, ensure you have the necessary Laravel version (5.8 and above). The Laravel documentation provides clear instructions on installing and configuring the Bus Chain.

Chaining Events

Now that your environment is set up, let’s dive into the heart of the matter – chaining events. With the Bus Chain, you can easily string together events, creating a sequential flow of actions.

This is achieved by implementing the ShouldQueue interface on your event classes, allowing Laravel to handle the events in the background, enhancing performance.

class FirstEvent implements ShouldQueue
{
    // Event logic here
}

class SecondEvent implements ShouldQueue
{
    // Event logic here
}

// In your controller or wherever you dispatch events
Bus::chain([
    new FirstEvent(),
    new SecondEvent(),
])->dispatch();

Benefits of Bus Chain

1. Orderly Execution:
   Ensure that your events are executed in a specific order, preventing race conditions and guaranteeing that each event has the necessary data or setup from the preceding one.
2. Improved Performance:
   By implementing the ShouldQueue interface, events in the Bus Chain are processed in the background, preventing any delays in your application’s response time.
3. Simplified Workflow:
   Streamline complex workflows by breaking them down into smaller, manageable events. This not only enhances code readability but also makes maintenance and debugging more straightforward.

Handling Failures in the Chain

Laravel’s Bus Chain includes robust error handling mechanisms. If a job in the chain fails, Laravel’s queue worker will automatically retry the job based on your configured settings.

Sample Configuration for Job Fail Retries:

To configure job fail retries, you can use the $tries property in your job class. For instance:

class SendEmailNotification implements ShouldQueue
{
    public $tries = 3; // Retry the job a maximum of 3 times

    // Event logic here

    public function handle()
    {
        // Job logic here
    }

    // Additional methods...
}

This job will be retried up to three times in case of failure.

Retries

If a job exhausts all its retry attempts and still fails, Laravel will log the failed job. You can configure how long Laravel should wait before retrying the job again using the $backoff property:

class SendEmailNotification implements ShouldQueue
{
    public $tries = 3; // Retry the job a maximum of 3 times
    public $backoff= 60; // Retry the job every 60 seconds

    // Event logic here

    public function handle()
    {
        // Job logic here
    }

    // Additional methods...
}

backoff can be defined also as a function that returns an integer, in case you need to do some calculation to know exactly the amount of time to wait.

After all retries are exhausted, the job will be marked as failed, and you can set up notifications or take other actions based on the failed job.

What Happens if job fails?

A very important point, If one job in the sequence fails, even after the retries, the rest of the jobs will not be run.

Real-World Use Case

Consider a scenario where you want to send a series of notifications to a user. By using the Bus Chain, you can dispatch individual events for each notification type, in this case we will recharge credit to an user, will update the payment status and send an SMS to the user to notify about the recharg, ensuring a sequential and organized delivery process.
We can do it with something like this

Bus::chain([
    new rechargeCredit($user, $amout),
    new updatePaymentStatus($payment),
    new SendSMSNotification($user),
])->dispatch();

Conclusion

In conclusion, Laravel’s Bus Chain is a powerful tool for orchestrating the execution of events in a clear and defined sequence. By leveraging this feature, developers can enhance the maintainability, performance, and organization of their applications.

The bus chain has several options to digg in, this is a quick presentation to know about the benfits of this gem that laravel provides us, for more information see the Laravel Documentation.

Don’t be afraid, Experiment with Bus Chains in your Laravel projects and discover the efficiency and elegance they bring to your event handling workflows.