Simple cron job to check if a scheduled backup was uploaded

monitor-backups.php

<?php
// usage: php -f monitor-backups.php -- "./myfolder" "[email protected]" "[email protected]"

$folder = $argv[1];
$email = $argv[2];
$from = $argv[3];
$delay = isset($argv[4]) ? $argv[4] : 2 * 24 * 60 * 60; // 48 hours by default

if (!is_dir($folder)) {
  throw new Exception("Folder does not exist.");
}

if (!$email) {
  throw new Exception("Missing e-mail.");
}

$rii = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($folder));
$files = array();
foreach ($rii as $file) {
    if ($file->isDir()) continue;
    $files[] = $file->getPathname();
}

$files = array_combine($files, array_map("filemtime", $files));
arsort($files);

$last_modified = reset($files);
if ($last_modified == false) {
  throw new Exception("No files found.");
}

if (time() - $last_modified > $delay) {
  $last_date = date("r", $last_modified);
  mail(
    $email,
    "Warning: Backup job failed",
    "No backups were uploaded since $last_date.",
    "From: $from"
  );
}
?>