00mjk / fork

A lightweight solution for running code concurrently in PHP

A lightweight solution for running PHP code concurrently

This package makes it easy to run PHP concurrently. Behind the scenes, concurrency is achieved by forking the main PHP process to one or more child tasks.

In this example, where we are going to call an imaginary slow API, all three closures will run at the same time.

use Spatie\Fork\Fork;

$results = Fork::new()
    ->run(
        fn () => (new Api)->fetchData(userId: 1),
        fn () => (new Api)->fetchData(userId: 2),
        fn () => (new Api)->fetchData(userId: 3),
    );

$results[0]; // fetched data of user 1
$results[1]; // fetched data of user 2
$results[2]; // fetched data of user 3

How it works under the hood

✨ In this video on YouTube, we explain how the package works internally.

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Requirements

This package requires PHP 8 and the pcntl extensions which is installed in many Unix and Mac systems by default.

❗️ pcntl only works in CLI processes, not in a web context.

Installation

You can install the package via composer:

composer require spatie/fork

Usage

You can pass as many closures as you want to run. They will be run concurrently. The run function will return an array with the return values of the executed closures.

use Spatie\Fork\Fork;

$results = Fork::new()
    ->run(
        function ()  {
            sleep(1);

            return 'result from task 1';
        },
        function ()  {
            sleep(1);

            return 'result from task 2';
        },
        function ()  {
            sleep(1);

            return 'result from task 3';
        },
    );

// this code will be reached this point after 1 second
$results[0]; // contains 'result from task 1'
$results[1]; // contains 'result from task 2'
$results[2]; // contains 'result from task 3'

Running code before and after each closure

If you need to execute some code before or after each callable passed to run, you can pass a callable to before or after methods. This callable passed will be executed in the child process right before or after the execution of the callable passed to run.

Using before and after in the child task

Here's an example where we are going to get a value from the database using a Laravel Eloquent model. In order to let the child task use the DB, it is necessary to reconnect to the DB. The closure passed to before will run in both child tasks that are created for the closures passed to run.

use App\Models\User;
use Illuminate\Support\Facades\DB;
use Spatie\Fork\Fork;

 Fork::new()
    ->before(fn () => DB::connection('mysql')->reconnect())
    ->run(
        fn () => User::find(1)->someLongRunningFunction(),
        fn () => User::find(2)->someLongRunningFunction(),
    );

If you need to perform some cleanup in the child task after the callable has run, you can use the after method on a Spatie\Fork\Fork instance.

Using before and after in the parent task.

If you need to let the callable passed to before or after run in the parent task, then you need to pass that callable to the parent argument.

use App\Models\User;
use Illuminate\Support\Facades\DB;
use Spatie\Fork\Fork;

 Fork::new()
    ->before(
        parent: fn() => echo 'this runs in the parent task'
    )
    ->run(
        fn () => User::find(1)->someLongRunningFunction(),
        fn () => User::find(2)->someLongRunningFunction(),
    );

You can also pass different closures, to be run in the child and the parent task

use Spatie\Fork\Fork;

Fork::new()
    ->before(
        child: fn() => echo 'this runs in the child task',
        parent: fn() => echo 'this runs in the parent task',
    )
    ->run(
        fn () => User::find(1)->someLongRunningFunction(),
        fn () => User::find(2)->someLongRunningFunction(),
    );

Returning data

All output data is gathered in an array and available as soon as all children are done. In this example, $results will contain three items:

$results = Fork::new()
    ->run(
        fn () => (new Api)->fetchData(userId: 1),
        fn () => (new Api)->fetchData(userId: 2),
        fn () => (new Api)->fetchData(userId: 3),
    );

The output is also available in the after callbacks, which are called whenever a child is done and not at the very end:

$results = Fork::new()
    ->after(
        child: fn (int $i) => echo $i, // 1, 2 and 3
        parent: fn (int $i) => echo $i, // 1, 2 and 3
    )
    ->run(
        fn () => 1,
        fn () => 2,
        fn () => 3,
    );

Finally, return values from child tasks are serialized using PHP's built-in serialize method. This means that you can return anything you can normally serialize in PHP, including objects:

$result = Fork::new()
    ->run(
        fn () => new DateTime('2021-01-01'),
        fn () => new DateTime('2021-01-02'),
    );

Configuring concurrency

By default, all callables will be run in parallel. You can however configure a maximum amount of concurrent processes:

$results = Fork::new()
    ->concurrent(2)
    ->run(
        fn () => 1,
        fn () => 2,
        fn () => 3,
    );

In this case, the first two functions will be run immediately and as soon as one of them finishes, the last one will start as well.

Testing

composer test

Changelog

Please see CHANGELOG for more information on what has changed recently.

Contributing

Please see CONTRIBUTING for details.

Security Vulnerabilities

Please review our security policy on how to report security vulnerabilities.

Credits

• Brent Roose
• Freek Van der Herten
• All Contributors

License

The MIT License (MIT). Please see License File for more information.