db-backup

#!/usr/bin/env php
<?php
namespace Loadsys\CakePHPShellScripts\DbBackup;

/**
 * Prints usage information and exits.
 *
 * @param string $script Typically set to basename($argv[0]) when the method is called.
 * @param int $exitCode The numeric exit code to return. 0 = success. >0 = failure.
 * @return void
 */
function usage($script = null, $exitCode = 0) {
	$script = $script ?: basename(__FILE__);
	$usage = <<<EOD

${script}
    Executes a mysqldump of the Cake app's `default` database
    into a ZIP file located in a backups/ folder in the project
    root (created if necessary). Outputs the ZIP file's size as
    a crude verification step. Should be run from the project
    root folder. Will exit with an error code of 1 if database
    credentials could not be obtained from the Cake app via the
    `db-credentials` script.

Usage:
    bin/${script}

EOD;

	echo $usage;
	exit($exitCode);
}

/**
 * Convert numeric bytes into human-readable format.
 *
 * Example: 1535 ==> 1.50K.
 * Note that this only works with integer byte values.
 *
 * @param int $bytes Integer number of bytes to translate.
 * @param int $decimals Number of decimal places to preserve in output.
 * @return string The converted value with the "closest" unit used.
 */
function human_filesize($bytes, $decimals = 2) {
	$sz = 'BKMGTPEZY';
	$factor = floor((strlen(intval($bytes)) - 1) / 3);
	return (sprintf("%.{$decimals}f", intval($bytes) / pow(1024, $factor)) + 0) . @$sz[$factor];
}

/**
 * main() ===================================================================
 */

if (isset($argv[1]) && $argv[1] == '-h') {
	usage();
}

// Set up variables.
$backupDir = 'backups';
$date = date('Ymd-His');
try {
	$credentialsScript = 'bin/db-credentials';
	if (!is_readable($credentialsScript)) {
		echo "!! DB credentials are not available. Aborting.";
		exit(3);
	}

	ob_start(); // Capture the shebang line from db-credentials.
	$db = include($credentialsScript);
	ob_get_clean(); // Flush it.

	if ($db instanceof \Exception) {
		echo $db->getMessage();
		exit(4);
	}
} catch (Exception $e) {
	echo $e->getMessage();
	exit(1);
}

// Create an appropriate password clause for the command line.
if (empty($db->password)) {
	$passClause = '';
} else {
	$passClause = ' --password=' . escapeshellcmd($db->password);
}

// Create the backup directory if it doesn't exist.
if(!file_exists($backupDir) || !is_dir($backupDir)) {
	mkdir($backupDir, 0777);
}

// Build the command lines to execute.
$sqlFile = $backupDir . "/{$db->database}_{$date}.sql";
$zipFile = "{$sqlFile}.zip";
$dumpCmd = "mysqldump --host={$db->host} --user={$db->username}{$passClause} {$db->database} > {$sqlFile}\n";
$compressCmd = "zip -jrq8 {$zipFile} {$sqlFile}; rm {$sqlFile}";
//echo $db->database . ' ' . $db->username . ' ' . $db->password . "\n";

// Execute the commands.
echo "## Backing up database '{$db->database}' to: {$zipFile}\n";
system($dumpCmd);
system($compressCmd);
echo "## Database backup complete: " . human_filesize(filesize($zipFile)) . PHP_EOL;