Drupal Fullstack

File: src/Service/YourService.php

<?php

declare(strict_types=1);

namespace Drupal\your_module\Service;

use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\Logger\LoggerChannelFactoryInterface;
use Drupal\Core\Database\Connection;
use Drupal\Core\Session\AccountProxyInterface;
use Psr\Log\LoggerInterface;

/**
 * Your service description.
 *
 * @todo Add detailed service documentation.
 */
class YourService {

  /**
   * The database connection.
   */
  protected readonly Connection $database;

  /**
   * The configuration factory.
   */
  protected readonly ConfigFactoryInterface $configFactory;

  /**
   * The logger.
   */
  protected readonly LoggerInterface $logger;

  /**
   * The current user.
   */
  protected readonly AccountProxyInterface $currentUser;

  /**
   * Constructs a new YourService object.
   */
  public function __construct(
    Connection $database,
    ConfigFactoryInterface $config_factory,
    LoggerChannelFactoryInterface $logger_factory,
    AccountProxyInterface $current_user
  ) {
    $this->database = $database;
    $this->configFactory = $config_factory;
    $this->logger = $logger_factory->get('your_module');
    $this->currentUser = $current_user;
  }

  /**
   * Example method: Do something useful.
   *
   * @param string $input
   *   The input parameter.
   *
   * @return array
   *   The result.
   */
  public function doSomething(string $input): array {
    $this->logger->info('Processing input: @input', ['@input' => $input]);

    // Your logic here
    $result = ['processed' => TRUE, 'data' => $input];

    return $result;
  }

}

Service Registration

File: your_module.services.yml