Understanding Laravel pipelines

1.ProcessClass.php

<?php
namespace App\Features;

use App\Features\FirstTask;
use App\Features\SecondTask;
use Illuminate\Pipeline\Pipeline;

// *Naming things is hard* ... So, this is a class called `ProcessClass` that `run()` some text ¯\_(ツ)_/¯

class ProcessClass
{
    protected $pipes;

    public function __construct()
    {
        $this->pipes = $this->loadPipes();
    }

    public function loadPipes()
    {
        return [
            FirstTask::class,
            SecondTask::class
        ];
    }

    public function run($text)
    {
        return app(Pipeline::class)
            ->send($text)
            ->through($this->pipes)
            ->then(function ($text) {
                return $text . "finally";
            });
    }
}

2.FirstTask.php

<?php

namespace App\Features;

use Closure;

class FirstTask
{
    /**
     * Changes the given text and return the result
     **/
    public function handle($text, Closure $next)
    {
        return $next($text . ' [first task] ');
    }
}

3.SecondTask.php

<?php

namespace App\Features;

use Closure;

class SecondTask
{
    /**
     * Changes the given text and return the result
     **/
    public function handle($text, Closure $next)
    {
        return $next($text . ' [second task] ');
    }
}

4.PipelineTest.php

<?php

namespace Tests\Feature;

use Tests\TestCase;
use App\Features\ProcessClass;

class PipelineTest extends TestCase
{

    public function testExample()
    {
        $text = 'Initial test';
        $object = new ProcessClass($text);
        $result = $object->run($text);
        $this->assertEquals('Initial test [first task]  [second task] finally', $result);
    }
}

5.RESULT.md

PHPUnit 6.2.4 by Sebastian Bergmann and contributors.

...                                                                 3 / 3 (100%)

Time: 136 ms, Memory: 14.00MB

OK (3 tests, 3 assertions)

Quick question: jumping out of a pipeline midway through - is that only possible by throwing an exception? For example, how does the Laravel middleware auth provider break the chain and issue a redirect if an auth task finds the user is not authenticated?

@judgej found anything? I was struggling with the same and found this to be good enough:

Registered a global exception handler for any exception a pipe might throw (bootstrap/app.php, ->withExceptions(function (Exceptions $exceptions) { in newer Laravel versions).

Example:

->withExceptions(function (Exceptions $exceptions) {
        $exceptions->render(function (\App\Exceptions\BusinessRuleViolationException $e, Request $request) {
             // return back() with errors

Each individual pipe would then of course throw new BusinessRuleViolationException when applicable, break the chain, and the user would see the error message I set.