Automatic drush aliases from git remotes.

aliases.drushrc.php

<?php
/** 
 * Place this file in e.g ~/.drush.
 * See `drush topic docs-aliases` for more info. 
 */

// Use require_once since this file is invoked multiple times.
require_once('git_remote_alias.php');
git_remote_alias_set('live', $aliases);
git_remote_alias_set('staging', $aliases);

git_remote_alias.php

<?php

function git_remote_alias_set($remote_name, &$aliases) {
  static $cache = array();
  
  if (!isset($cache[$remote_name])) {
    drush_shell_exec("git config --get remote.$remote_name.url");
    $uri = array_shift(drush_shell_exec_output());

    if (empty($uri)) {
      $cache[$remote_name] = FALSE;
    }
    else {
      // Handle ssh://user@host/path as well as user@host:path
      if (strpos($uri, 'ssh://') === false) {
        $uri = 'ssh://' . str_replace(':', '', $uri);
      } 

      $ssh_settings = parse_url($uri);

      $cache[$remote_name] = array(
        'remote-host' => $ssh_settings['host'],
        'remote-user' => $ssh_settings['user'],
        'root' => $ssh_settings['path'],
        'uri' => $ssh_settings['host'],
      );
    }
  };

  // Only add the alias if there is a remote on this repo with the given name.
  if ($cache[$remote_name]) {
    $aliases['self.' . $remote_name] = $cache[$remote_name];
  }
}