hosting_site_diff

This is an Aegir 2.4 module for comparing site configuration setups. It is cuurently missing its main functionality.

The code can be found at Drupal.org: https://www.drupal.org/sandbox/cahodk/2502585

This is a mini article explaining the module.

Aegir tasks

Aegir has a frontend and a backend (called hosing and provision). The frontend lets the administrator setup new platforms, sites, tasks etc. The backend runs drush commands in the context of the sites controlled by Aegir.

Hosting modules are installed as regular modules in the hostmaster folder, while Provision modules are installed as drush extension in the .drush directory.

This module consist of hosting_site_diff and provision_site_diff.

In hosting_site_diff I define a new hosting task:

/**
 * Implements hook_hosting_tasks().
 */
function hosting_site_diff_hosting_tasks() {
  $tasks = array();

  $tasks['site']['snapshot'] = array(
    'title' => t('Config Snapshot'),
    'description' => t('Make a snapshot available for site diff.'),
    'dialog' => TRUE,
    'hidden' => FALSE,
  );

  return $tasks;
}

/**
 * Implements hook_node_operations().
 */
function hosting_site_diff_node_operations() {
  $operations = array();

  $operations['site-diff-snapshot'] = array(
    'label' => t('Site: Config Snapshot'),
    'callback' => 'site_diff_op_snapshot',
  );

  return $operations;
}

/**
 * Callback for site diff operation.
 */
function hosting_site_diff_op_snapshot($nodes) {
  foreach ($nodes as $nid) {
    hosting_add_task($nid, 'site_diff_snapshot');
  }
}

I now have a new frontend task available Snapshot. But before I can actually execute it, it needs a backend function to get triggered. I define that in provision_site_diff (the drush extension). I leave the function empty, because I'm not going to use it. If all I needed to do, was run commands in the context of a site, I would do it from here, but I need to save to the db of Aegir - the solution is the next step.

/**
 * Implementation of hook_drush_command().
 */
function provision_site_diff_drush_command() {
  $items['provision-snapshot'] = array(
    'description' => 'Saves a timestamped config snapshot of a site.',
    'bootstrap' => DRUSH_BOOTSTRAP_DRUSH,
  );

  return $items;
}

/**
 * Implements the provision-snapshot command.
 */
function drush_provision_site_diff_provision_snapshot() {
  // EMPTY
}

Next, as written above, since I need to write to Aegirs DB, I have to listen for the task in a .drush.inc file in hosting_site_diff:

/**
* Implementation of drush_hook_pre_hosting_task()
*/
function drush_hosting_site_diff_post_hosting_task() {
  $task =& drush_get_context('HOSTING_TASK');
  if ($task->ref->type == 'site' && ($task->task_type == 'snapshot')) {
    //...do stuff
  }
}

The rest is regular Drupal :)