streams/Code/Lib/DB_Upgrade.php

<?php

namespace Code\Lib;

use App;
use Code\Render\Theme;


class DB_Upgrade
{

    public $config_name = '';
    public $func_prefix = '';

    public function __construct($db_revision)
    {

        $this->config_name = 'db_version';
        $this->func_prefix = '_';

        $build = get_config('system', 'db_version', 0);
        if (!(int)$build) {
            $build = set_config('system', 'db_version', $db_revision);
        }

        if ((int)$build === (int)$db_revision) {
            // Nothing to be done.
            return;
        } else {
            $storedVersion = (int)$build;
            if (!$storedVersion) {
                logger('Critical: check_config unable to determine database schema version');
                return;
            }

            $newVersion = (int)$db_revision;

            if ($storedVersion < $newVersion) {
                // The last update we performed was $stored.
                // Start at $stored + 1 and continue until we have completed $current

                for ($currentUpdate = $storedVersion + 1; $currentUpdate <= $newVersion; $currentUpdate++) {
                    $configString = '_' . $currentUpdate;
                    $updateClass = '\\Code\Update\\' . $configString;
                    if (!class_exists($updateClass)) {
                        return;
                    }

                    // There could be a lot of processes running or about to run.
                    // We want exactly one process to run the update command.
                    // So store the fact that we're taking responsibility
                    // after first checking to see if somebody else already has.

                    // If the update fails or times-out completely you may need to
                    // delete the config entry to try again.

                    Config::Load('database');

                    if (get_config('database', $configString)) {
                        break;
                    }
                    set_config('database', $configString, '1');


                    $update = new $updateClass();

                    $retval = $update->run();

                    if ($retval != UPDATE_SUCCESS) {
                        $source = t('Source code of failed update: ') . "\n\n" . @file_get_contents('Code/Update/' . $configString . '.php');


                        // Prevent sending hundreds of thousands of emails by creating
                        // a lockfile.

                        $lockfile = 'cache/mailsent';

                        if ((file_exists($lockfile)) && (filemtime($lockfile) > (time() - 86400))) {
                            return;
                        }
                        @unlink($lockfile);
                        //send the administrator an e-mail
                        file_put_contents($lockfile, $currentUpdate);

                        $r = q(
                            "select account_language from account where account_email = '%s' limit 1",
                            dbesc(App::$config['system']['admin_email'])
                        );
                        push_lang(($r) ? $r[0]['account_language'] : 'en');
                        z_mail(
                            [
                                'toEmail' => App::$config['system']['admin_email'],
                                'messageSubject' => sprintf(t('Update Error at %s'), z_root()),
                                'textVersion' => replace_macros(
                                    Theme::get_email_template('update_fail_eml.tpl'),
                                    [
                                        '$sitename' => App::$config['system']['sitename'],
                                        '$siteurl' => z_root(),
                                        '$update' => $currentUpdate,
                                        '$error' => sprintf(t('Update %s failed. See error logs.'), $currentUpdate),
                                        '$baseurl' => z_root(),
                                        '$source' => $source
                                    ]
                                )
                            ]
                        );

                        //try the logger
                        logger('CRITICAL: Update Failed: ' . $currentUpdate);
                        pop_lang();
                    } else {
                        set_config('database', $configString, 'success');
                    }
                }
            }
            set_config('system', 'db_version', $db_revision);
        }
    }
}