BatchAPIHookUpdate

batch_api_example.php

<?php

use Drupal\node\Entity\Node;

/**
 * Implements hook_update_N().
 * Patch Content of Type article.
 */
function xyz_update_9001(&$sandbox) {
  // Get count only if $sandbox['max'] is not set i.e the first time.
  if (!isset($sandbox['max'])) {
    // Get total number of articles in the site.
    $articlesCount = \Drupal::entityQuery('node')
      ->condition('type', 'article', '=')
      ->count()
      ->execute();
  }

  // Use the sandbox to store the information needed to track progression.
  if (!isset($sandbox['current']))
  {
    // Initialize the current count first time.
    $sandbox['current'] = 0;
    // Set Total number of entities first time.
    $sandbox['max'] = $articlesCount ?? 0;
  }

  // Process entities in groups of 30. 
  // When a group is processed, the batch update engine determines
  // whether it should continue processing in the same request or provide
  // progress feedback to the user and wait for the next request.
  
  // Possiblle get this value from config or environment variable.
  $limit = 30;
  
  // Limit to 30 article in one batch.
  $articles = \Drupal::entityQuery('node')
    ->condition('type', 'article', '=')
    ->fetchAll()
    ->range($sandbox['current'], $limit)
    ->execute();

  foreach ($articles as $key => $value) {
    $node = Node::load($value->uid);
    if ($node->get('field_author') === 'XYZ') {
      $node->set('field_publication', 'Penguin');
    }
    else if ($node->get('field_author') === 'PQR') {
      $node->set('field_publication', 'Ether');
    }
    // Save the node.
    $node->save();
    // Increment the number of processed nodes.
    $sandbox['current']++;
    // Decrement the reamining nodes count.
    $sandbox['max']--;
  }

  // check if we have processed all the nodes.
  if ($sandbox['max'] == 0) {
    // Setting #finished >= 1, stops the batch,
    $sandbox['#finished'] = 1;
  } else {
    $sandbox['#finished'] = ($sandbox['current'] / $sandbox['max']);
  }
}