Batch API drush command running once then shows Solr error

Question

I am trying to create a drush command to run a batch process. When I run the command, the batch runs just once, and I get this error :

in Drupal\search_api_solr\SolrConnector\SolrConnectorPluginBase->handleHttpException() (line 1026 of /var/www/html/web/modules/contrib/search_api_solr/src/SolrConnector/SolrConnectorPluginBase.php). Drupal\search_api_solr\SearchApiSolrException: Solr endpoint http://solr:8983/ not found (code: 404

This is my code, am I doing something wrong? Thanks for your help:

class Drush9CustomCommands extends DrushCommands {

  use StringTranslationTrait;
  private $entityTypeManager;
  protected $logger;
  protected $batchService;
  
  public function __construct(EntityTypeManagerInterface $entityTypeManager, LoggerInterface $logger, BatchService $batch_service) {
    parent::__construct();
    $this->entityTypeManager = $entityTypeManager;
    $this->logger = $logger;
    $this->batchService = $batch_service;
  }

  /**
   * Update Node.
   *
   * @command update:node
   * @aliases update-node
   *
   * @usage update:node foo
   *   foo is the type of node to update
   */
  public function updateNode() {

    $batch = array(
      'title' => t('Exporting'),
      'operations' => array(
        array([$this->batchService,'processMyNode'], array()),
      ),
      'finished' => [$this->batchService,'processMyNodeFinished'],
    );
    batch_set($batch);

    drush_backend_batch_process();
  }
}

Batchservice.php

class BatchService implements ContainerInjectionInterface {

  use StringTranslationTrait;
  protected $messenger;

  public function __construct(MessengerInterface $messenger) {
    $this->messenger = $messenger;
  }

  /**
   * {@inheritDoc}
   */
  public static function create(ContainerInterface $container) {
    return new static(
      $container->get('messenger')
    );
  }

  /**
   * Batch process callback.
   *
   * @param int $id
   *   Id of the batch.
   * @param string $operation_details
   *   Details of the operation.
   * @param object $context
   *   Context for operations.
   */
  public function processMyNode( &$context) {
    if (!isset($context['sandbox']['total'])) {
      // Get node experience ids.
      $query = \Drupal::entityTypeManager()->getStorage('node')->getQuery();
      $nids = $query
        ->condition('type', 'mynode')
        ->range(0,1000)
        ->accessCheck(FALSE)
        ->execute();

      $context['sandbox']['total'] = count($nids);
      $context['sandbox']['node_ids'] = $nids;
      $context['sandbox']['current'] = 0;
    }
    $node_ids = array_slice($context['sandbox']['node_ids'], $context['sandbox']['current'], 25);

    foreach ($node_ids as $nid) {
      $node = \Drupal::entityTypeManager()->getStorage('node')->load($nid);
      $node->set('field_my_field', 'my field value');
      $node->save();
    }

    $context['sandbox']['current'] += count($node_ids);

    \Drupal::logger('test')->notice($context['sandbox']['current'] . ' Experiences passed / ' . $context['sandbox']['total']);

    if ($context['sandbox']['total'] == 0) {
      $context['sandbox']['#finished'] = 1;
    }
    else {

      $context['sandbox']['#finished'] = ($context['sandbox']['current'] / $context['sandbox']['total']);
    }
  }

  /**
   * Batch Finished callback.
   *
   * @param bool $success
   *   Success of the operation.
   * @param array $results
   *   Array of results for post processing.
   * @param array $operations
   *   Array of operations.
   */
  public  function processMyNodeFinished($success, array $results, array $operations) {

    if ($success) {
      $message = \Drupal::translation()->formatPlural(count($results), 'One post processed.', '@count posts processed.');
    }
    else {
      $message = t('Finished with an error.');
    }
    \Drupal::logger('teset')->notice($message);
  }

}

Answer 1

Search API Solr module cannot connect to the configured Solr server instance each time the script saves a node. The configured Solr instance is http://solr:8983/. You must configure a reachable instance.

Answer 2

Adding to @cilefen's answer, there was en error in the code : it should be $context['finished'] instead of $context['sandbox']['#finished'].After modifying this, the batch was running successfully.