Drupal 9 batch api example using BatchBuilder

DeleteFeeds.php

<?php

namespace Drupal\miax_content\Command;

use Drupal\Core\Batch\BatchBuilder;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Logger\LoggerChannelFactoryInterface;
use Drupal\Core\StringTranslation\StringTranslationTrait;
use Drush\Commands\DrushCommands;
use Drupal\miax_content\Services\DeleteFeedsBatchService;

/**
 * A Drush commandfile.
 *
 * In addition to this file, you need a drush.services.yml
 * in root of your module, and a composer.json file that provides the name
 * of the services file to use.
 *
 * See these files for an example of injecting Drupal services:
 *   - http://cgit.drupalcode.org/devel/tree/src/Commands/DevelCommands.php
 *   - http://cgit.drupalcode.org/devel/tree/drush.services.yml
 */
class DeleteFeeds extends DrushCommands {

  use StringTranslationTrait;

  /**
   * Entity type service.
   *
   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
   */
  private $entityTypeManager;

  /**
   * Logger service.
   *
   * @var \Drupal\Core\Logger\LoggerChannelFactoryInterface
   */
  private $loggerChannelFactory;

  /**
   * Feeds batch service.
   *
   * @var \Drupal\miax_content\Services\DeleteFeedsBatchService
   */
  private $deleteFeedsBatchService;

  /**
   * Constructs a new UpdateVideosStatsController object.
   *
   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entityTypeManager
   *   Entity type service.
   * @param \Drupal\Core\Logger\LoggerChannelFactoryInterface $loggerChannelFactory
   *   Logger service.
   * @param \Drupal\miax_content\Services\FeedsBatchService $feedsBatchService
   *   Feeds batch service.
   */
  public function __construct(EntityTypeManagerInterface $entityTypeManager, LoggerChannelFactoryInterface $loggerChannelFactory, DeleteFeedsBatchService $deleteFeedsBatchService) {
    $this->entityTypeManager = $entityTypeManager;
    $this->loggerChannelFactory = $loggerChannelFactory;
    $this->deleteFeedsBatchService = $deleteFeedsBatchService;
  }

  /**
   * Delete the feeds of a given type.
   *
   * @param string $type
   *   Type of feed to update
   *   Argument provided to the drush command.
   *
   * @command test:feeds:delete-feeds
   * @aliases test-fdel
   *
   * @usage test:feeds:delete-feeds foo
   *   foo is the type of feeds to delete.
   */
  public function deleteFeed($type = '') {
    // Ask for confirmation as this operation can not be undone.
    $this->io()->warning(dt('This operation can not be undone. Are you sure you want to delete all feeds of type @type?', ['@type' => $type]));

    $confirm = $this->io()->confirm(dt('Are you sure you want to delete all feeds of type @type?', ['@type' => $type]));
    if (!$confirm) {
      return;
    }

    // 1. Log the start of the script.
    $this->loggerChannelFactory->get('miax_content')->info('Feeds @type delete batch operations start', ['@type' => $type]);

    // Check the type of node given as argument, if not, set article as default.
    if (strlen($type) == 0) {
      print "No type of feed given, please provide a type of feed to delete.";
      return;
    }

    // 2. Retrieve all feeds of this type.
    try {
      $storage = $this->entityTypeManager->getStorage('feeds_feed');
      $query = $storage->getQuery()
        ->condition('type', $type);
        // ->range(0, 1);
      $fids = $query->execute();
    }
    catch (\Exception $e) {
      $this->output()->writeln($e);
      $this->loggerChannelFactory->get('miax_content')->warning('Error found @e', ['@e' => $e]);
    }

    // 3. Create the operations array for the batch.
    $batchBuilder = new BatchBuilder();
    // $operations = [];
    $numOperations = 0;
    $batchId = 1;

    if (!empty($fids)) {
      foreach ($fids as $fid) {
        // Prepare the operation. Here we could do other operations on nodes.
        $this->output()->writeln($this->t('Preparing batch: ') . $batchId);

        $batchBuilder->addOperation([$this->deleteFeedsBatchService, 'deleteFeed'], [
          $batchId,
          $fid,
        ]);

        $batchId++;
        $numOperations++;
      }
    }
    else {
      $this->logger->warning($this->t('No feeds of this type @type', ['@type' => $type]));
    }

    // 4. Create the batch.
    $batchBuilder
      ->setTitle($this->t('Deleting @num node(s)', ['@num' => $numOperations]))
      ->setFinishCallback([$this->deleteFeedsBatchService, 'deleteFeedFinished'])
      ->setErrorMessage($this->t('Batch has encountered an error'));

    // 5. Add batch operations as new batch sets.
    batch_set($batchBuilder->toArray());

    // 6. Process the batch sets.
    drush_backend_batch_process();

    // 6. Show some information.
    $this->logger()->notice($this->t("Batch operations end."));
    // 7. Log some information.
    $this->loggerChannelFactory->get('miax_content')->info($this->t('Delete batch operations end.'));
  }

}

DeleteFeedsBatchService.php

<?php

namespace Drupal\miax_content\Services;

use Drupal\Core\StringTranslation\StringTranslationTrait;
use Drupal\Core\DependencyInjection\DependencySerializationTrait;

/**
 * Class DeleteFeedsBatchService provides the batch processing delete for feeds.
 */
class DeleteFeedsBatchService {

  use StringTranslationTrait;
  use DependencySerializationTrait;

  /**
   * Batch process callback.
   *
   * @param int $id
   *   Id of the batch.
   * @param string $fid
   *   Feed id.
   * @param object $context
   *   Context for operations.
   */
  public function deleteFeed($id, $fid, &$context) {

    // Simulate long process by waiting 100 microseconds.
    // usleep(100);

    // Delete the feed.
    $feed = \Drupal::entityTypeManager()->getStorage('feeds_feed')->load($fid);
    // print($feed->label());
    // die;
    // $feed->delete();

    // Store some results for post-processing in the 'finished' callback.
    // The contents of 'results' will be available as $results in the
    // 'finished' function (in this example, batch_example_finished()).
    $context['results'][] = $id;
    $context['results'][] = $feed->label();

    // Optional message displayed under the progressbar.
    $context['message'] = $this->t('Running Batch "@id" @fid',
      ['@id' => $id, '@fid' => $feed->label()]
    );

  }

  /**
   * Batch Finished callback.
   *
   * @param bool $success
   *   Success of the operation.
   * @param array $results
   *   Array of results for post processing.
   * @param array $operations
   *   Array of operations.
   */
  public function deleteFeedFinished($success, array $results, array $operations) {
    $messenger = \Drupal::messenger();
    if ($success) {
      // Here we could do something meaningful with the results.
      // We just display the number of nodes we processed...
      $messenger->addMessage($this->t('@count results processed.', ['@count' => count($results)]));
    }
    else {
      // An error occurred.
      // $operations contains the operations that remained unprocessed.
      $error_operation = reset($operations);
      $messenger->addMessage(
        $this->t('An error occurred while processing @operation with arguments : @args',
          [
            '@operation' => $error_operation[0],
            '@args' => print_r($error_operation[0], TRUE),
          ]
        )
      );
    }
  }

}