How to Make Commands Lazily Loaded

Warning: You are browsing the documentation for Symfony 6.2, which is no longer maintained.

Read the updated version of this page for Symfony 7.2 (the current stable version).

How to Make Commands Lazily Loaded

Note

If you are using the Symfony full-stack framework, you are probably looking for details about creating lazy commands

The traditional way of adding commands to your application is to use add(), which expects a Command instance as an argument.

In order to lazy-load commands, you need to register an intermediate loader which will be responsible for returning Command instances:

1
2
3
4
5
6
7
8
9
10
11
12
use App\Command\HeavyCommand;
use Symfony\Component\Console\Application;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\CommandLoader\FactoryCommandLoader;

$commandLoader = new FactoryCommandLoader([
    'app:heavy' => function (): Command { return new HeavyCommand(); },
]);

$application = new Application();
$application->setCommandLoader($commandLoader);
$application->run();

This way, the HeavyCommand instance will be created only when the app:heavy command is actually called.

This example makes use of the built-in FactoryCommandLoader class, but the setCommandLoader() method accepts any CommandLoaderInterface instance so you can use your own implementation.

Built-in Command Loaders

FactoryCommandLoader

The FactoryCommandLoader class provides a way of getting commands lazily loaded as it takes an array of Command factories as its only constructor argument:

1
2
3
4
5
6
7
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\CommandLoader\FactoryCommandLoader;

$commandLoader = new FactoryCommandLoader([
    'app:foo' => function (): Command { return new FooCommand(); },
    'app:bar' => [BarCommand::class, 'create'],
]);

Factories can be any PHP callable and will be executed each time get() is called.

ContainerCommandLoader

The ContainerCommandLoader class can be used to load commands from a PSR-11 container. As such, its constructor takes a PSR-11 ContainerInterface implementation as its first argument and a command map as its last argument. The command map must be an array with command names as keys and service identifiers as values:

1
2
3
4
5
6
7
8
9
10
use Symfony\Component\Console\CommandLoader\ContainerCommandLoader;
use Symfony\Component\DependencyInjection\ContainerBuilder;

$container = new ContainerBuilder();
$container->register(FooCommand::class, FooCommand::class);
$container->compile();

$commandLoader = new ContainerCommandLoader($container, [
    'app:foo' => FooCommand::class,
]);

Like this, executing the app:foo command will load the FooCommand service by calling $container->get(FooCommand::class).

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.
TOC
    Version