Determine if a migration is running

MigrationIsRunning.php

<?php


namespace Drupal\ras_comments;

use Drupal\migrate\Event\MigrateEvents;
use Drupal\migrate\Event\MigrateImportEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;

/**
 * Class CommentEventSubscriber.
 *
 * Sets a temporary variable to identify that this process is a migration
 * process. Used during the comment mail hook to disable emails.
 *
 * @package Drupal\ras_comments
 */
class CommentEventSubscriber implements EventSubscriberInterface {

  const DISABLE_VARIABLE = 'ras_comments_email_disable';

  /**
   * The drupal_static cache.
   *
   * @var array
   */
  protected $staticCache;

  /**
   * CommentEventSubscriber constructor.
   */
  public function __construct() {
    $this->staticCache = &drupal_static(self::DISABLE_VARIABLE);
  }

  /**
   * Get subscribed events.
   *
   * @inheritdoc
   */
  public static function getSubscribedEvents() {
    return [
      MigrateEvents::PRE_IMPORT => 'onMigratePreImport',
      MigrateEvents::POST_IMPORT => 'onMigratePostImport',
    ];
  }

  /**
   * Listener onMigratePreImport.
   *
   * Set the blocking variable.
   *
   * @param \Drupal\migrate\Event\MigrateImportEvent $importEvent
   *   The import event object.
   */
  public function onMigratePreImport(MigrateImportEvent $importEvent) {
    if ($importEvent->getMigration()->getBaseId() == 'typo3_comment') {
      $this->staticCache = TRUE;
    }
  }

  /**
   * Listener onMigratePostSave.
   *
   * Set the blocking variable to FALSE, in case anything else needs to create
   * a comment in this process.
   *
   * @param \Drupal\migrate\Event\MigrateImportEvent $importEvent
   *   The import event object.
   */
  public function onMigratePostImport(MigrateImportEvent $importEvent) {
    if ($importEvent->getMigration()->getBaseId() == 'typo3_comment') {
      $this->staticCache = FALSE;
    }
  }
}