Drush configuration for git repositories

aliases.drushrc.php

<?php
/**
 * @file
 * Drush alias file for git repositories
 * with predefined options for sql-dump command
 * 
 * Place as etc/drush/aliases.drushrc.php 
 * within your git repository 
 *
 * @see http://netzaffe.de/node/1608 for details about repository structure
 * @see http://drupal.org/project/drush_sql_dump_hold for hold option
 * @see etc/drush/git.drushrc.php for modifying structure-tables-key array
 */

exec('git rev-parse --git-dir 2> /dev/null', $output);
if (!empty($output)) {
  $repo = $output[0];
  $aliases['git'] = array(
    'uri' => 'default',
    'root' =>  realpath($repo . '/../drupal'),
    'command-specific' => array (
      'sql-dump' => array(
        'result-file' => TRUE,
        'result-file' => realpath($repo . '/../dumps/') . '/@DATABASE_@DATE.sql',
        'gzip' => TRUE,
        'structure-tables-key' => 'common',
        // Do not use strict, 
        // suppress errors, if drush_dump_hold (hold option) is not available.
        'strict' => FALSE,
        // Additional hold option from https://drupal.org/project/drush_sql_dump_hold.
        'hold' => 31,
        // Always confirm purge with yes.
        'yes' => TRUE,
      ),
    ),
  );
}

example.drushrc.php

<?php

/**
 * @file
 * example.drushrc.php for git repositories
 * 
 * Tries to load git.drushrc.php as additional config
 * and searches for aliases in specified $options['alias-path'] 
 * if we are within a git repository.
 *
 * @see http://netzaffe.de/node/1608 for details about git repository structure.
 *
 * Rename this file to drushrc.php and optionally copy it to one of
 * convenient places, or append the code below to the end of 
 * listed below locations in order of precedence: 
 *
 * 1. Drupal site folder (e.g sites/{default|example.com}/drushrc.php).
 * 2. Drupal installation root.
 * 3. In any location, as specified by the --config (-c) option.
 * 4. User's .drush folder (i.e. ~/.drush/drushrc.php).
 * 5. System wide configuration folder (e.g. /etc/drush/drushrc.php).
 * 6. Drush installation folder.
 * 
 */

exec('git rev-parse --git-dir 2> /dev/null', $output);
if (!empty($output)) {
  $repo = $output[0];
  $options['config'] = $repo . '/../etc/drush/git.drushrc.php';
  $options['alias-path'] = $repo . '/../etc/drush';
}

git.drushrc.php

<?php
/**
 * @file
 * Specifific drushrc.php for git repositories
 *
 * Place as etc/drush/git.drushrc.php 
 * within your git repository
 *
 * @see http://netzaffe.de/node/1608 for details about repository structure
 */

exec('git rev-parse --git-dir 2> /dev/null', $output);
if (!empty($output)) {
  $repo = $output[0];
  $options['r'] = realpath($repo . '/../drupal');
  $options['l'] = 'default';
  $options['structure-tables']['common'] = array(
    'accesslog', 'cache', 'cache_block', 
    'cache_filter', 'cache_form', 'cache_menu', 
    'cache_page', 'cache_update', 'history', 
    'search_dataset', 'search_index', 'search_total', 
    'sessions', 'watchdog',
  );
}