How to change DB active config storage of an installed site to config file storage?

Question

The default.settings.php says

/**
 * Active configuration settings.
 *
 * By default, the active configuration is stored in the database in the
 * {config} table. To use a different storage mechanism for the active
 * configuration, do the following prior to installing:
 * - Override the 'bootstrap_config_storage' setting here. It must be set to a
 *   callable that returns an object that implements
 *   \Drupal\Core\Config\StorageInterface.
 * - Override the service definition 'config.storage.active'. Put this
 *   override in a services.yml file in the same directory as settings.php
 *   (definitions in this file will override service definition defaults).
 */
# $settings['bootstrap_config_storage'] = array('Drupal\Core\Config\BootstrapConfigStorageFactory', 'getFileStorage');

I have added above code to my settings.php and this is the piece of code I have added in services.yml before install.

services:
  config.storage.active:
    class: Drupal\Core\Config\FileStorage
    factory_class: Drupal\Core\Config\FileStorageFactory
    factory_method: getActive
    public: false

How can I change the DB config storage to file config storage after site install? We have config_db.module to change it form file storage to DB storage. Do we have a module to change it from DB storage to file storage?

Answer 1

Here are the steps I followed:

1) Export settings to your current $config_directories['sync'] directory (by default it is defined in settings.php and it is something like 'sites/default/files/config_VerYlonGkEY0123/sync')

$ drush cex

2) Create these directories (should be writable):

config/
  active/
  staging/
  sync/

3) Copy/paste all files from $config_directories['sync'] to config/active/

4) Add the new settings to settings.php

$config_directories = array(
  CONFIG_ACTIVE_DIRECTORY => DRUPAL_ROOT . '/config/active',
  CONFIG_STAGING_DIRECTORY => DRUPAL_ROOT . '/config/staging',
  CONFIG_SYNC_DIRECTORY => DRUPAL_ROOT . '/config/sync',
);

$settings['bootstrap_config_storage'] = array('Drupal\Core\Config\BootstrapConfigStorageFactory', 'getFileStorage');

5) Add this to service.yml (in the same directory as the settings.php):

services:
  config.storage:
    class: Drupal\Core\Config\CachedStorage
    arguments: ['@config.storage.active', '@cache.config']
  config.storage.active:
    class: Drupal\Core\Config\FileStorage
    factory: Drupal\Core\Config\FileStorageFactory::getActive

6) Export the settings to sync:

$ drush cex sync

Than you should have the settings in config/sync :)