Enabling Drupal modules in update hooks

Parent Feed:

It is becoming more and more common with instances of continuous integration and testing to do any configuration through code. This is true of enabling modules as well reverting Features using hook_update_N() to carry those actions out. The problem with just putting module_enable() in an update hook is that even if the module enable fails, the hook_update_N is considered a success, so there is no way to re-run the specific hook_update. With a pair of helper functions, it is possible for the update hook to be considered a failure if a module does not enable. Considering it a failure allows you to resolve the issue and re-attempt the update hook.

Here is what the update hook to enable two modules might look like. Notice it calls a custom function rather than just module_enable().

/**
 * Enables book and og_book.
 */
function mymodule_update_7001(&$sandbox) {
  $modules = array(
    'book',
    'og_book',
  );
  $return = mymodule_module_enable($modules);

return </span>$return;
}
?>

Here are the two helper functions that enable the modules and check to makes sure they were actually enabled.

/**
 * Check to see if the modules are actually enabled.
 *
 * @param array $modules
 *   An array of module machine names to check for being enabled.
 *
 * @return string
 *   Messsage indicating the modules are enabled
 *
 * @throws DrupalUpdateException
 *   Calls the update a failure, preventing it from registering the update_N.
 */
function mymodule_check_modules_enabled($modules = array()) {
  $modules = (array) $modules;
  $return = TRUE;
  $enabled_modules = array();
  $t = get_t();
  // Check to see if each module is enabled.
  foreach ($modules as $module) {
    if (!module_exists($module)) {
      // This module is not enabled, throw an exception.
      throw new DrupalUpdateException($t('The module @module was supposed to be enabled by this update, but was not. Please investigate the problem and re-run this update.',array('@module' => $module)));
    }
  }
  $module_list = implode(', ', $modules);
  return </span>$t('The modules @enabled were enabled successfully.', array('@enabled' => $module_list));
}
/**
 * Enables an array of modules and checks to make sure they were truly enabled.
 *
 * @param array $modules
 *   An array of module machine names to check for being enabled.
 *
 * @return string
 *   Messsage indicating the modules are enabled.
 *
 * @throws DrupalUpdateException
 *   Calls the update a failure, preventing it from registering the update_N.
 */
function mymodule_module_enable($modules = array()) {
  $modules = (array) $modules;
  $enable_good = module_enable($modules);
  if (!$enable_good) {
    // Enable command failed.
    $module_list = implode(', ', $modules);
    $t = get_t();
    throw new DrupalUpdateException($t('The requested modules @modules to be enabled by this update, were not, because one of them does not exist in the codebase. Please investigate the problem and re-run this update.',array('@modules' => $module_list)));
  }
  // There are cases where $enable_good is TRUE but the module may not have enabled, so double check.
  $success = mymodule_check_modules_enabled($modules);

return </span>$success;
}
?>

Author:

swirt

Original Post:

http://web-dev.wirt.us/info/drupal/enabling-drupal-modules-update-hooks

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