Drupal 8 Configuration Dependency Injection

my_module.module.php

<?php

/**
 * Get my setting.
 */
function get_my_setting() {
  return /Drupal::service('my_module.my_service')->getMySetting();
}

my_module.services.yml

services:
  my_module.my_service:
    class: Drupal\my_module\Services\MyService
    arguments:
      - '@config.factory'

my_module.settings.yml

# /my_module/config/install/
my_setting: "Foo"

MyService.php

<?php

namespace Drupal\my_module\Services;

use Drupal\Core\Config\ConfigFactory;

/**
 * Class MyService.
 *
 * @package Drupal\my_module\Services
 */
class MyService {
  
  /**
   * Configuration Factory.
   *
   * @var \Drupal\Core\Config\ConfigFactory
   */
  protected $configFactory;
  
  /**
   * Constructor.
   */
  public function __construct(ConfigFactory $configFactory) {
    $this->configFactory = $configFactory;
  }
  
  /**
   * Gets my setting.
   */
  public function getMySetting() {
    $config = $this->configFactory->get('my_module.settings');
    return $config->get('my_setting');
  }
  
}

Thank you for posting

👍