Automatic drush alias generation based on directory

localhost.aliases.drushrc.php

<?php

$root = "/home/rob/Sites/";
$allowed_dirs = [
	'web',
	'wwwroot',
	'build',
];

foreach (new DirectoryIterator($root) as $main_dir) {
	if ($main_dir->isDot() || !$main_dir->isDir()) { continue; }
	foreach (new DirectoryIterator($main_dir->getPath() . '/' . $main_dir->getFilename()) as $sub_dir) {
		if ($sub_dir->isDot() || !$sub_dir->isDir()) { continue; }
		if ($sub_dir->getFilename() == '.git') { continue; }
		foreach ($allowed_dirs as $check_dir) {
			if (file_exists($sub_dir->getPath() . '/' . $sub_dir->getFilename() . '/' . $check_dir)) {
				$dir = $check_dir;
				break;
			}
		}	
		if (isset($dir)) {
			$aliases[$sub_dir->getFilename()] = [
				'root' => $sub_dir->getPath() . '/' . $sub_dir->getFilename() . '/' . $dir, 
				'uri' => $main_dir->getFilename() . '.' . $sub_dir->getFilename() . '.' . $dir . '.dev',
			];
			unset($dir);
		}
	}
}