memcacheSync.php

#!/usr/bin/env php
<?php


// Check that the memcache library is enabled
if (!class_exists('Memcache')) {
    echo("Error: the memcache library appears to be unavailable.\n");
    echo("\n");
    echo("This is most likely because PHP doesn't load it for the command line\n");
    echo("version. You probably need to enable it somehow.\n");
    echo("\n");
    if (is_dir('/etc/php5/cli/conf.d')) {
        echo("It is possible that running the following command as root will fix it:\n");
        echo(" echo 'extension=memcache.so' >/etc/php5/cli/conf.d/memcache.ini\n");
    }

    exit(1);
}

// This is the base directory of the SimpleSAMLphp installation
$baseDir = dirname(dirname(__FILE__));

// Add library autoloader
require_once($baseDir.'/lib/_autoload.php');

// Initialize the configuration
$configdir = SimpleSAML\Utils\Config::getConfigDir();
SimpleSAML_Configuration::setConfigDir($configdir);

// Things we should warn the user about
$warnServerDown = 0;
$warnBigSlab = 0;

// We use the stats interface to determine which servers exists
$stats = SimpleSAML_Memcache::getRawStats();

$keys = array();
foreach ($stats as $group) {
    foreach ($group as $server => $state) {

        if ($state === false) {
            echo("WARNING: Server ".$server." is down.\n");
            $warnServerDown++;
            continue;
        }

        $items = $state['curr_items'];
        echo("Server ".$server." has ".$items." items.\n");
        $serverKeys = getServerKeys($server);
        $keys = array_merge($keys, $serverKeys);
    }
}

echo("Total number of keys: ".count($keys)."\n");
$keys = array_unique($keys);
echo("Total number of unique keys: ".count($keys)."\n");

echo("Starting synchronization.\n");

$skipped = 0;
$sync = 0;
foreach ($keys as $key) {
    $res = SimpleSAML_Memcache::get($key);
    if ($res === null) {
        $skipped += 1;
    } else {
        $sync += 1;
    }
}


echo("Synchronization done.\n");
echo($sync." keys in sync.\n");
if ($skipped > 0) {
    echo($skipped." keys skipped.\n");
    echo("Keys are skipped because they are either expired, or are of a type unknown\n");
    echo("to SimpleSAMLphp.\n");
}

if ($warnServerDown > 0) {
    echo("WARNING: ".$warnServerDown." server(s) down. Not all servers are synchronized.\n");
}

if ($warnBigSlab > 0) {
    echo("WARNING: ".$warnBigSlab." slab(s) may have contained more keys than we were told about.\n");
}

/**
 * Fetch all keys available in an server.
 *
 * @param string $server The server, as a string with <hostname>:<port>.
 *
 * @return array An array with all the keys available on the server.
 */
function getServerKeys($server)
{
    $server = explode(':', $server);
    $host = $server[0];
    $port = (int) $server[1];

    echo("Connecting to: ".$host.":".$port."\n");
    $socket = fsockopen($host, $port);
    echo("Connected. Finding keys.\n");

    if (fwrite($socket, "stats slabs\r\n") === false) {
        echo("Error requesting slab dump from server.\n");
        exit(1);
    }

    // Read list of slabs
    $slabs = array();
    while (($line = fgets($socket)) !== false) {
        $line = rtrim($line);
        if ($line === 'END') {
            break;
        }

        if (preg_match('/^STAT (\d+):/', $line, $matches)) {
            $slab = (int) $matches[1];
            if (!in_array($slab, $slabs, true)) {
                $slabs[] = $slab;
            }
        }
    }

    // Dump keys in slabs
    $keys = array();
    foreach ($slabs as $slab) {

        if (fwrite($socket, "stats cachedump ".$slab." 1000000\r\n") === false) {
            echo("Error requesting cache dump from server.\n");
            exit(1);
        }

        /* We keep track of the result size, to be able to warn the user if it is
         * so big that keys may have been lost.
         */
        $resultSize = 0;

        while (($line = fgets($socket)) !== false) {
            $resultSize += strlen($line);

            $line = rtrim($line);
            if ($line === 'END') {
                break;
            }

            if (preg_match('/^ITEM (.*) \[\d+ b; \d+ s\]/', $line, $matches)) {
                $keys[] = $matches[1];
            } else {
                echo("Unknown result from cache dump: ".$line."\n");
            }
        }
        if ($resultSize > 1900000 || count($keys) >= 1000000) {
            echo("WARNING: Slab ".$slab." on server ".$host.":".$port.
                " may have contained more keys than we were told about.\n");
            $GLOBALS['warnBigSlab'] += 1;
        }
    }

    echo("Found ".count($keys)." key(s).\n");
    fclose($socket);

    return $keys;
}