hook_init() equivalent for console command

Question

I have a module which subscribes to the kernel.request event to set some environment variables for use with LDAP. E.g. setting the LDAP_CACERT environment variable. I'm using it to replace hook_init() as recommended at https://www.drupal.org/node/2013014. However, I've noticed that it does not seem to set the environment variables at the start of Drush commands. E.g. I'd want the environment variables set in a PHP console or a cron run. This is part of a re-useable module so just adding it to settings.php is suboptimal.

What's the best way to execute code before any arbitrary Drush command runs?

I've found the console.command event which says:

The COMMAND event allows you to attach listeners before any command is executed by the console. It also allows you to modify the command, input and output before they are handled to the command.

I had hoped that would work with Drush 9. I've added it to my subscriber like so:

/**
  * {@inheritdoc}
  */
public static function getSubscribedEvents() {
  $events['kernel.request'] = ['setLdapEnvVariablesWeb'];
  $events['console.command'] = ['setLdapEnvVariablesCli'];
  return $events;
}

public function setLdapEnvVariablesCli(ConsoleCommandEvent $event) {
  $this->setLdapEnvVariables();
}

but unfortunately it never seems to be hit, even though I can see from drupal debug:event console.command that Drupal does recognize I am subscribed to it.

It would be nice if I could handle this in the same subscriber as for web requests but I am not set on it.

Answer 1

I've found out what's going on with this. It appears that Drush uses its own event dispatcher separate from Drupal's and that's where the console command event is actually dispatched. That means I need to manually add a listener to Drush's event dispatcher like so:

\Drush\Drush::service('eventDispatcher')->addListener('console.command', 'Drupal\mymodule\EventSubscriber\DefaultSubscriber::setLdapEnvVariablesCli');

Unfortunately there's still a problem: I need to add that subscriber somewhere that's called before the start of the command in order to be able to call things before the start of the command.

I ended up having to actually subscribe to the Drush event dispatcher event in settings.php:

if (function_exists('drush_main') && method_exists('Drush\Drush', 'service')) {
  \Drush\Drush::service('eventDispatcher')->addListener('console.command', 'Drupal\mymodule\EventSubscriber\DefaultSubscriber::setLdapEnvVariablesCli');
}

This isn't ideal but it does at least let me keep most of the actual logic in the subscriber.

then I made the CLI callback method and the common method static:

public static function setLdapEnvVariablesCli(ConsoleCommandEvent $event) {
  self::setLdapEnvVariables();
}

protected static function setLdapEnvVariables() {
  // ...
}

It's a bit ugly but it works. I'll just have to document that a settings.php change is needed in the module README.

Answer 2

I had a similar requirement to load environment variables for the request (vault) but the console.command event didn't seem to dispatch in drush (v10) so I just did this, as an alternative:

/**
 * Load environment variables for drush CLI
 */
if(PHP_SAPI === 'cli') {
  \Drupal\my_module\EventSubscriber\EnvironmentVariable::load();
}

with a static function in the event listener similar to:

public static function load() {
  // Load vault variables
  self::loadVault();
}

edit: here's another way to add an init hook for current drush, using @hook in the Drush command file

<?php
namespace Drupal\my_module\Commands;

use Consolidation\AnnotatedCommand\AnnotationData;
use Symfony\Component\Console\Input\InputInterface;
use Drupal\my_module\EventSubscriber\EnvironmentVariable;

class MyModuleDrushCommands extends DrushCommands {

  /**
   * @hook init *
   */
  public function loadEnvironmentVariables(InputInterface $input, AnnotationData $annotationData) {
    EnvironmentVariable::load();
  }

  // ..
}

More info: https://github.com/consolidation/annotated-command#initialize-hook