Issue #2004370 by xjm, alexpott, Dean Reilly: Batch the configuration synchronisation process.

core/includes/batch.inc

@@ -411,7 +411,7 @@ function _batch_finished() {
       if (is_callable($batch_set['finished'])) {
         $queue = _batch_queue($batch_set);
         $operations = $queue->getAllItems();
-        $batch_set['finished']($batch_set['success'], $batch_set['results'], $operations, format_interval($batch_set['elapsed'] / 1000));
+        call_user_func_array($batch_set['finished'], array($batch_set['success'], $batch_set['results'], $operations, format_interval($batch_set['elapsed'] / 1000)));
       }
     }
   }

core/lib/Drupal/Core/Config/BatchConfigImporter.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Config\BatchConfigImporter.
+ */
+
+namespace Drupal\Core\Config;
+
+/**
+ * Defines a batch configuration importer.
+ *
+ * @see \Drupal\Core\Config\ConfigImporter
+ */
+class BatchConfigImporter extends ConfigImporter {
+
+  /**
+   * Initializes the config importer in preparation for processing a batch.
+   */
+  public function initialize() {
+    // Ensure that the changes have been validated.
+    $this->validate();
+
+    if (!$this->lock->acquire(static::ID)) {
+      // Another process is synchronizing configuration.
+      throw new ConfigImporterException(sprintf('%s is already importing', static::ID));
+    }
+    $this->totalToProcess = 0;
+    foreach(array('create', 'delete', 'update') as $op) {
+      $this->totalToProcess += count($this->getUnprocessed($op));
+    }
+  }
+
+  /**
+   * Processes batch.
+   *
+   * @param array $context.
+   *   The batch context.
+   */
+  public function processBatch(array &$context) {
+    $operation = $this->getNextOperation();
+    if (!empty($operation)) {
+      $this->process($operation['op'], $operation['name']);
+      $context['message'] = t('Synchronizing @name.', array('@name' => $operation['name']));
+      $context['finished'] = $this->batchProgress();
+    }
+    else {
+      $context['finished'] = 1;
+    }
+    if ($context['finished'] >= 1) {
+      $this->notify('import');
+      // The import is now complete.
+      $this->lock->release(static::ID);
+      $this->reset();
+    }
+  }
+
+  /**
+   * Gets percentage of progress made.
+   *
+   * @return float
+   *   The percentage of progress made expressed as a float between 0 and 1.
+   */
+  protected  function batchProgress() {
+    $processed_count = count($this->processed['create']) + count($this->processed['delete']) + count($this->processed['update']);
+    return $processed_count / $this->totalToProcess;
+  }
+
+  /**
+   * Gets the next operation to perform.
+   *
+   * @return array|bool
+   *   An array containing the next operation and configuration name to perform
+   *   it on. If there is nothing left to do returns FALSE;
+   */
+  protected  function getNextOperation() {
+    foreach(array('create', 'delete', 'update') as $op) {
+      $names = $this->getUnprocessed($op);
+      if (!empty($names)) {
+        return array(
+          'op' => $op,
+          'name' => array_shift($names),
+        );
+      }
+    }
+    return FALSE;
+  }
+}

core/lib/Drupal/Core/Config/ConfigImporter.php

@@ -7,6 +7,7 @@
 
 namespace Drupal\Core\Config;
 
+use Drupal\Core\DependencyInjection\DependencySerialization;
 use Drupal\Core\Lock\LockBackendInterface;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
 
@@ -29,7 +30,7 @@
  *
  * @see \Drupal\Core\Config\ConfigImporterEvent
  */
-class ConfigImporter {
+class ConfigImporter extends DependencySerialization {
 
   /**
    * The name used to identify events and the lock.
@@ -204,8 +205,15 @@ public function import() {
         // Another process is synchronizing configuration.
         throw new ConfigImporterException(sprintf('%s is already importing', static::ID));
       }
-      $this->importInvokeOwner();
-      $this->importConfig();
+      // First pass deleted, then new, and lastly changed configuration, in order
+      // to handle dependencies correctly.
+      // @todo Implement proper dependency ordering using
+      //   https://drupal.org/node/2080823
+      foreach (array('delete', 'create', 'update') as $op) {
+        foreach ($this->getUnprocessed($op) as $name) {
+          $this->process($op, $name);
+        }
+      }
       // Allow modules to react to a import.
       $this->notify('import');
 
@@ -234,25 +242,40 @@ public function validate() {
   }
 
   /**
-   * Writes an array of config changes from the source to the target storage.
+   * Processes a configuration change.
+   *
+   * @param string $op
+   *   The change operation.
+   * @param string $name
+   *   The name of the configuration to process.
    */
-  protected function importConfig() {
-    foreach (array('delete', 'create', 'update') as $op) {
-      foreach ($this->getUnprocessed($op) as $name) {
-        $config = new Config($name, $this->storageComparer->getTargetStorage(), $this->eventDispatcher, $this->typedConfigManager);
-        if ($op == 'delete') {
-          $config->delete();
-        }
-        else {
-          $data = $this->storageComparer->getSourceStorage()->read($name);
-          $config->setData($data ? $data : array());
-          $config->save();
-        }
-        $this->setProcessed($op, $name);
-      }
+  protected function process($op, $name) {
+    if (!$this->importInvokeOwner($op, $name)) {
+      $this->importConfig($op, $name);
     }
   }
 
+  /**
+   * Writes a configuration change from the source to the target storage.
+   *
+   * @param string $op
+   *   The change operation.
+   * @param string $name
+   *   The name of the configuration to process.
+   */
+  protected function importConfig($op, $name) {
+    $config = new Config($name, $this->storageComparer->getTargetStorage(), $this->eventDispatcher, $this->typedConfigManager);
+    if ($op == 'delete') {
+      $config->delete();
+    }
+    else {
+      $data = $this->storageComparer->getSourceStorage()->read($name);
+      $config->setData($data ? $data : array());
+      $config->save();
+    }
+    $this->setProcessed($op, $name);
+  }
+
   /**
    * Invokes import* methods on configuration entity storage controllers.
    *
@@ -260,37 +283,43 @@ protected function importConfig() {
    * configuration data.
    *
    * @todo Add support for other extension types; e.g., themes etc.
+   *
+   * @param string $op
+   *   The change operation to get the unprocessed list for, either delete,
+   *   create or update.
+   * @param string $name
+   *   The name of the configuration to process.
+   *
+   * @return bool
+   *   TRUE if the configuration was imported as a configuration entity. FALSE
+   *   otherwise.
    */
-  protected function importInvokeOwner() {
-    // First pass deleted, then new, and lastly changed configuration, in order
-    // to handle dependencies correctly.
-    foreach (array('delete', 'create', 'update') as $op) {
-      foreach ($this->getUnprocessed($op) as $name) {
-        // Call to the configuration entity's storage controller to handle the
-        // configuration change.
-        $handled_by_module = FALSE;
-        // Validate the configuration object name before importing it.
-        // Config::validateName($name);
-        if ($entity_type = $this->configManager->getEntityTypeIdByName($name)) {
-          $old_config = new Config($name, $this->storageComparer->getTargetStorage(), $this->eventDispatcher, $this->typedConfigManager);
-          if ($old_data = $this->storageComparer->getTargetStorage()->read($name)) {
-            $old_config->initWithData($old_data);
-          }
-
-          $data = $this->storageComparer->getSourceStorage()->read($name);
-          $new_config = new Config($name, $this->storageComparer->getTargetStorage(), $this->eventDispatcher, $this->typedConfigManager);
-          if ($data !== FALSE) {
-            $new_config->setData($data);
-          }
-
-          $method = 'import' . ucfirst($op);
-          $handled_by_module = $this->configManager->getEntityManager()->getStorageController($entity_type)->$method($name, $new_config, $old_config);
-        }
-        if (!empty($handled_by_module)) {
-          $this->setProcessed($op, $name);
-        }
+  protected function importInvokeOwner($op, $name) {
+    // Call to the configuration entity's storage controller to handle the
+    // configuration change.
+    $handled_by_module = FALSE;
+    // Validate the configuration object name before importing it.
+    // Config::validateName($name);
+    if ($entity_type = $this->configManager->getEntityTypeIdByName($name)) {
+      $old_config = new Config($name, $this->storageComparer->getTargetStorage(), $this->eventDispatcher, $this->typedConfigManager);
+      if ($old_data = $this->storageComparer->getTargetStorage()->read($name)) {
+        $old_config->initWithData($old_data);
+      }
+
+      $data = $this->storageComparer->getSourceStorage()->read($name);
+      $new_config = new Config($name, $this->storageComparer->getTargetStorage(), $this->eventDispatcher, $this->typedConfigManager);
+      if ($data !== FALSE) {
+        $new_config->setData($data);
       }
+
+      $method = 'import' . ucfirst($op);
+      $handled_by_module = $this->configManager->getEntityManager()->getStorageController($entity_type)->$method($name, $new_config, $old_config);
+    }
+    if (!empty($handled_by_module)) {
+      $this->setProcessed($op, $name);
+      return TRUE;
     }
+    return FALSE;
   }
 
   /**

core/modules/config/lib/Drupal/config/Form/ConfigSync.php

@@ -11,9 +11,8 @@
 use Drupal\Core\Form\FormBase;
 use Drupal\Core\Config\StorageInterface;
 use Drupal\Core\Lock\LockBackendInterface;
+use Drupal\Core\Config\BatchConfigImporter;
 use Drupal\Core\Config\StorageComparer;
-use Drupal\Core\Config\ConfigImporter;
-use Drupal\Core\Config\ConfigException;
 use Drupal\Core\Config\TypedConfigManager;
 use Drupal\Core\Routing\UrlGeneratorInterface;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
@@ -218,7 +217,7 @@ public function buildForm(array $form, array &$form_state) {
    * {@inheritdoc}
    */
   public function submitForm(array &$form, array &$form_state) {
-    $config_importer = new ConfigImporter(
+    $config_importer = new BatchConfigImporter(
       $form_state['storage_comparer'],
       $this->eventDispatcher,
       $this->configManager,
@@ -229,21 +228,59 @@ public function submitForm(array &$form, array &$form_state) {
       drupal_set_message($this->t('Another request may be synchronizing configuration already.'));
     }
     else{
-      try {
-        $config_importer->import();
-        drupal_flush_all_caches();
-        drupal_set_message($this->t('The configuration was imported successfully.'));
-      }
-      catch (ConfigException $e) {
-        // Return a negative result for UI purposes. We do not differentiate
-        // between an actual synchronization error and a failed lock, because
-        // concurrent synchronizations are an edge-case happening only when
-        // multiple developers or site builders attempt to do it without
-        // coordinating.
-        watchdog_exception('config_import', $e);
-        drupal_set_message($this->t('The import failed due to an error. Any errors have been logged.'), 'error');
-      }
+      $config_importer->initialize();
+      $batch = array(
+        'operations' => array(
+          array(array(get_class($this), 'processBatch'), array($config_importer)),
+        ),
+        'finished' => array(get_class($this), 'finishBatch'),
+        'title' => t('Synchronizing configuration'),
+        'init_message' => t('Starting configuration synchronization.'),
+        'progress_message' => t('Synchronized @current configuration files out of @total.'),
+        'error_message' => t('Configuration synchronization has encountered an error.'),
+        'file' => drupal_get_path('module', 'config') . '/config.admin.inc',
+      );
+
+      batch_set($batch);
+    }
+  }
+
+  /**
+   * Processes the config import batch and persists the importer.
+   *
+   * @param BatchConfigImporter $config_importer
+   *   The batch config importer object to persist.
+   * @param $context
+   *   The batch context.
+   */
+  public static function processBatch(BatchConfigImporter $config_importer, &$context) {
+    if (!isset($context['sandbox']['config_importer'])) {
+      $context['sandbox']['config_importer'] = $config_importer;
     }
+
+    $config_importer = $context['sandbox']['config_importer'];
+    $config_importer->processBatch($context);
+  }
+
+  /**
+   * Finish batch.
+   *
+   * This function is a static function to avoid serialising the ConfigSync
+   * object unnecessarily.
+   */
+  public static function finishBatch($success, $results, $operations) {
+    if ($success) {
+      drupal_set_message(\Drupal::translation()->translate('The configuration was imported successfully.'));
+    }
+    else {
+      // An error occurred.
+      // $operations contains the operations that remained unprocessed.
+      $error_operation = reset($operations);
+      $message = \Drupal::translation()->translate('An error occurred while processing %error_operation with arguments: @arguments', array('%error_operation' => $error_operation[0], '@arguments' => print_r($error_operation[1], TRUE)));
+      drupal_set_message($message, 'error');
+    }
+    drupal_flush_all_caches();
   }
 
+
 }