How to Define Commands as Services
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Read the updated version of this page for Symfony 7.1 (the current stable version).
By default, Symfony will take a look in the Command
directory of each
bundle and automatically register your commands. If a command extends the
ContainerAwareCommand,
Symfony will even inject the container.
While making life easier, this has some limitations:
- Your command must live in the
Command
directory; - There's no way to conditionally register your command based on the environment or availability of some dependencies;
- You can't access the container in the
configure()
method (becausesetContainer()
hasn't been called yet); - You can't use the same class to create many commands (i.e. each with different configuration).
To solve these problems, you can register your command as a service and tag it
with console.command
:
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# app/config/services.yml
services:
app.command.my_command:
class: AppBundle\Command\MyCommand
tags:
- { name: console.command }
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<!-- app/config/services.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://symfony.com/schema/dic/services
http://symfony.com/schema/dic/services/services-1.0.xsd">
<services>
<service id="app.command.my_command"
class="AppBundle\Command\MyCommand">
<tag name="console.command" />
</service>
</services>
</container>
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// app/config/services.php
use AppBundle\Command\MyCommand;
$container
->register('app.command.my_command', MyCommand::class)
->addTag('console.command')
;
Using Dependencies and Parameters to Set Default Values for Options
Imagine you want to provide a default value for the name
option. You could
pass one of the following as the 5th argument of addOption()
:
- a hardcoded string;
- a container parameter (e.g. something from
parameters.yml
); - a value computed by a service (e.g. a repository).
By extending ContainerAwareCommand
, only the first is possible, because you
can't access the container inside the configure()
method. Instead, inject
any parameter or service you need into the constructor. For example, suppose you
store the default value in some %command.default_name%
parameter:
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// src/AppBundle/Command/GreetCommand.php
namespace AppBundle\Command;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;
class GreetCommand extends Command
{
protected $defaultName;
public function __construct($defaultName)
{
$this->defaultName = $defaultName;
parent::__construct();
}
protected function configure()
{
// try to avoid work here (e.g. database query)
// this method is *always* called - see warning below
$this
->setName('demo:greet')
->setDescription('Greet someone')
->addOption(
'name',
'-n',
InputOption::VALUE_REQUIRED,
'Who do you want to greet?',
$this->defaultName
)
;
}
protected function execute(InputInterface $input, OutputInterface $output)
{
$name = $input->getOption('name');
$output->writeln($name);
}
}
Now, just update the arguments of your service configuration like normal to
inject the command.default_name
parameter:
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# app/config/config.yml
parameters:
command.default_name: Javier
services:
app.command.my_command:
class: AppBundle\Command\MyCommand
arguments: ["%command.default_name%"]
tags:
- { name: console.command }
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<!-- app/config/config.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://symfony.com/schema/dic/services
http://symfony.com/schema/dic/services/services-1.0.xsd">
<parameters>
<parameter key="command.default_name">Javier</parameter>
</parameters>
<services>
<service id="app.command.my_command"
class="AppBundle\Command\MyCommand">
<argument>%command.default_name%</argument>
<tag name="console.command" />
</service>
</services>
</container>
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// app/config/config.php
use AppBundle\Command\MyCommand;
$container->setParameter('command.default_name', 'Javier');
$container
->register('app.command.my_command', MyCommand::class)
->setArguments(array('%command.default_name%'))
->addTag('console.command')
;
Great, you now have a dynamic default value!
Caution
Be careful not to actually do any work in configure
(e.g. make database
queries), as your code will be run, even if you're using the console to
execute a different command.