Programmatically import configs

import_configs.php

/**
 * Import configs that may be needed for any further updates.
 * These files should be placed in config/install/[update_id] in this module for initial
 * installation. The configs should also be placed in /config/default for all future
 * modifications.
 *
 * Based on https://stackoverflow.com/a/52277490/1650120.
 *
 * @param string $update_id
 *  The name of the folder in containing the yml files.
 *  Folder should be placed in this helper module in config/install.
 *
 * @return array
 *  Array of updated and created entity ids.
 */
function _import_configs(string $update_id) {
  // Get list of all files in $update_id directory.
  $path = drupal_get_path('DEMO', 'DEMO_helper') . '/config/install/' . $update_id;
  $files = array();
  $directory = new DirectoryIterator($path);
  foreach ($directory as $fileinfo) {
    if (!$fileinfo->isDot()) {
      $files[] = $path . '/' . $fileinfo->getFilename();
    }
  }
  // The ConfigManager class provides helper functions for the configuration system.
  $config_manager = \Drupal::service('config.manager');
  // Create empty arrays for returning update information.
  $updated = array();
  $created = array();
  // Import the configs from each file.
  foreach ($files as $file) {
    // Get configuration information from yml file.
    $raw = file_get_contents($file);
    $value = \Drupal\Component\Serialization\Yaml::decode($raw);
    if(!is_array($value)) {
      throw new \RuntimeException(sprintf('Invalid YAML file %s'), $file);
    }
    // Gets EntityManagerInterface - the entity manager.
    $entity_manager = $config_manager->getEntityManager();
    // Get the entity type of a configuration object - ie
    // block_content.type.homepage_hero.yml will get block_content_type.
    $entity_type = $config_manager->getEntityTypeIdByName(basename($file));
    // Gets EntityTypeInterface of entity type in current config.
    $definition = $entity_manager->getDefinition($entity_type);
    // Gets entity id.
    $id_key = $definition->getKey('id');
    // Yml config file has been serialized into an array. Get the id.
    // For example from field.storage.block_content.field_paragraph.yml it is
    // 'homepage_hero'
    $id = $value[$id_key];
    // Gets EntityStorageInterface - a storage instance.
    $entity_storage = $entity_manager->getStorage($entity_type);
    // Load an entity based on its entity id.
    $entity = $entity_storage->load($id);
    // If entity already exists, update. Else create a new one.
    if ($entity) {
      $entity = $entity_storage->updateFromStorageRecord($entity, $value);
      $entity->save();
      $updated[] = $id;
    }
    else {
      $entity = $entity_storage->createFromStorageRecord($value);
      $entity->save();
      $created[] = $id;
    }
  }
  // Return results of update/create entities (if needed).
  return [
    'updated' => $updated,
    'created' => $created,
  ];
}