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See Release Notes

  • Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
  • Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
  • PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * Redis Cache Store - Main library
 *
 * @package   cachestore_redis
 * @copyright 2013 Adam Durana
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die();

/**
 * Redis Cache Store
 *
 * To allow separation of definitions in Moodle and faster purging, each cache
 * is implemented as a Redis hash.  That is a trade-off between having functionality of TTL
 * and being able to manage many caches in a single redis instance.  Given the recommendation
 * not to use TTL if at all possible and the benefits of having many stores in Redis using the
 * hash configuration, the hash implementation has been used.
 *
 * @copyright   2013 Adam Durana
 * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class cachestore_redis extends cache_store implements cache_is_key_aware, cache_is_lockable,
        cache_is_configurable, cache_is_searchable {
    /**
     * Compressor: none.
     */
    const COMPRESSOR_NONE = 0;

    /**
     * Compressor: PHP GZip.
     */
    const COMPRESSOR_PHP_GZIP = 1;

    /**
     * Compressor: PHP Zstandard.
     */
    const COMPRESSOR_PHP_ZSTD = 2;

    /**
> * @var string Suffix used on key name (for hash) to store the TTL sorted list * Name of this store. > */ * > const TTL_SUFFIX = '_ttl'; * @var string > */ > /** protected $name; > * @var int Number of items to delete from cache in one batch when expiring old TTL data. > */ /** > const TTL_EXPIRE_BATCH = 10000; * The definition hash, used for hash key > * > /**
* @var string */ protected $hash; /** * Flag for readiness! * * @var boolean */ protected $isready = false; /** * Cache definition for this store. * * @var cache_definition */ protected $definition = null; /** * Connection to Redis for this store. * * @var Redis */ protected $redis; /** * Serializer for this store. * * @var int */ protected $serializer = Redis::SERIALIZER_PHP; /** * Compressor for this store. * * @var int */ protected $compressor = self::COMPRESSOR_NONE; /**
> * Bytes read or written by last call to set()/get() or set_many()/get_many(). * Determines if the requirements for this type of store are met. > * * > * @var int * @return bool > */ */ > protected $lastiobytes = 0; public static function are_requirements_met() { > return class_exists('Redis'); > /** @var int Maximum number of seconds to wait for a lock before giving up. */ } > protected $lockwait = 60; > /** > /** @var int Timeout before lock is automatically released (in case of crashes) */ * Determines if this type of store supports a given mode. > protected $locktimeout = 600; * > * @param int $mode > /** @var ?array Array of current locks, or null if we haven't registered shutdown function */ * @return bool > protected $currentlocks = null; */ > public static function is_supported_mode($mode) { > /**
return ($mode === self::MODE_APPLICATION || $mode === self::MODE_SESSION); } /** * Get the features of this type of cache store. * * @param array $configuration * @return int */ public static function get_supported_features(array $configuration = array()) {
> // Although this plugin now supports TTL I did not add SUPPORTS_NATIVE_TTL here, because return self::SUPPORTS_DATA_GUARANTEE + self::DEREFERENCES_OBJECTS + self::IS_SEARCHABLE; > // doing so would cause Moodle to stop adding a 'TTL wrapper' to data items which enforces } > // the precise specified TTL. Unless the scheduled task is set to run rather frequently, > // this could cause change in behaviour. Maybe later this should be reconsidered...
/** * Get the supported modes of this type of cache store. * * @param array $configuration * @return int */ public static function get_supported_modes(array $configuration = array()) { return self::MODE_APPLICATION + self::MODE_SESSION; } /** * Constructs an instance of this type of store. * * @param string $name * @param array $configuration */ public function __construct($name, array $configuration = array()) { $this->name = $name; if (!array_key_exists('server', $configuration) || empty($configuration['server'])) { return; } if (array_key_exists('serializer', $configuration)) { $this->serializer = (int)$configuration['serializer']; } if (array_key_exists('compressor', $configuration)) { $this->compressor = (int)$configuration['compressor']; } $password = !empty($configuration['password']) ? $configuration['password'] : ''; $prefix = !empty($configuration['prefix']) ? $configuration['prefix'] : '';
> if (array_key_exists('lockwait', $configuration)) { $this->redis = $this->new_redis($configuration['server'], $prefix, $password); > $this->lockwait = (int)$configuration['lockwait']; } > } > if (array_key_exists('locktimeout', $configuration)) { /** > $this->locktimeout = (int)$configuration['locktimeout']; * Create a new Redis instance and > }
* connect to the server. * * @param string $server The server connection string * @param string $prefix The key prefix * @param string $password The server connection password * @return Redis */ protected function new_redis($server, $prefix = '', $password = '') { $redis = new Redis();
< // Check if it isn't a Unix socket to set default port. < $port = ($server[0] === '/') ? null : 6379; < if (strpos($server, ':')) {
> // Check for Unix socket. > if ($server[0] === '/') { > $port = 0; > } else { > $port = 6379; // No Unix socket so set default port. > if (strpos($server, ':')) { // Check for custom port.
$serverconf = explode(':', $server); $server = $serverconf[0]; $port = $serverconf[1]; }
> }
try { if ($redis->connect($server, $port)) { if (!empty($password)) { $redis->auth($password); } // If using compressor, serialisation will be done at cachestore level, not php-redis. if ($this->compressor == self::COMPRESSOR_NONE) { $redis->setOption(Redis::OPT_SERIALIZER, $this->serializer); } if (!empty($prefix)) { $redis->setOption(Redis::OPT_PREFIX, $prefix); }
< // Database setting option... < $this->isready = $this->ping($redis);
> $this->isready = true;
} else { $this->isready = false; } } catch (\RedisException $e) { $this->isready = false; } return $redis; } /** * See if we can ping Redis server * * @param Redis $redis * @return bool */ protected function ping(Redis $redis) { try { if ($redis->ping() === false) { return false; } } catch (Exception $e) { return false; } return true; } /** * Get the name of the store. * * @return string */ public function my_name() { return $this->name; } /** * Initialize the store. * * @param cache_definition $definition * @return bool */ public function initialise(cache_definition $definition) { $this->definition = $definition; $this->hash = $definition->generate_definition_hash(); return true; } /** * Determine if the store is initialized. * * @return bool */ public function is_initialised() { return ($this->definition !== null); } /** * Determine if the store is ready for use. * * @return bool */ public function is_ready() { return $this->isready; } /** * Get the value associated with a given key. * * @param string $key The key to get the value of. * @return mixed The value of the key, or false if there is no value associated with the key. */ public function get($key) { $value = $this->redis->hGet($this->hash, $key); if ($this->compressor == self::COMPRESSOR_NONE) { return $value; }
> // When using compression, values are always strings, so strlen will work. return $this->uncompress($value); > $this->lastiobytes = strlen($value); } >
/** * Get the values associated with a list of keys. * * @param array $keys The keys to get the values of. * @return array An array of the values of the given keys. */ public function get_many($keys) { $values = $this->redis->hMGet($this->hash, $keys); if ($this->compressor == self::COMPRESSOR_NONE) { return $values; }
> $this->lastiobytes = 0;
foreach ($values as &$value) {
> $this->lastiobytes += strlen($value);
$value = $this->uncompress($value); } return $values; } /**
> * Gets the number of bytes read from or written to cache as a result of the last action. * Set the value of a key. > * * > * If compression is not enabled, this function always returns IO_BYTES_NOT_SUPPORTED. The reason is that * @param string $key The key to set the value of. > * when compression is not enabled, data sent to the cache is not serialized, and we would * @param mixed $value The value. > * need to serialize it to compute the size, which would have a significant performance cost. * @return bool True if the operation succeeded, false otherwise. > * */ > * @return int Bytes read or written public function set($key, $value) { > * @since Moodle 4.0 if ($this->compressor != self::COMPRESSOR_NONE) { > */ $value = $this->compress($value); > public function get_last_io_bytes(): int { } > if ($this->compressor != self::COMPRESSOR_NONE) { > return $this->lastiobytes; return ($this->redis->hSet($this->hash, $key, $value) !== false); > } else { } > // Not supported unless compression is on. > return parent::get_last_io_bytes(); /** > } * Set the values of many keys. > } * > * @param array $keyvaluearray An array of key/value pairs. Each item in the array is an associative array > /**
* with two keys, 'key' and 'value'.
> $this->lastiobytes = strlen($value);
< return ($this->redis->hSet($this->hash, $key, $value) !== false);
> if ($this->redis->hSet($this->hash, $key, $value) === false) { > return false; > } > if ($this->definition->get_ttl()) { > // When TTL is enabled, we also store the key name in a list sorted by the current time. > $this->redis->zAdd($this->hash . self::TTL_SUFFIX, [], self::get_time(), $key); > // The return value to the zAdd function never indicates whether the operation succeeded > // (it returns zero when there was no error if the item is already in the list) so we > // ignore it. > } > return true;
*/ public function set_many(array $keyvaluearray) { $pairs = [];
> $usettl = false; foreach ($keyvaluearray as $pair) { > if ($this->definition->get_ttl()) { $key = $pair['key']; > $usettl = true; if ($this->compressor != self::COMPRESSOR_NONE) { > $ttlparams = []; $pairs[$key] = $this->compress($pair['value']); > $now = self::get_time(); } else { > } $pairs[$key] = $pair['value']; > } > $this->lastiobytes = 0;
}
> $this->lastiobytes += strlen($pairs[$key]);
if ($this->redis->hMSet($this->hash, $pairs)) {
> if ($usettl) { return count($pairs); > // When TTL is enabled, we also store the key names in a list sorted by the current } > // time. return 0; > $ttlparams[] = $now; } > $ttlparams[] = $key; > } /** > } * Delete the given key. > if ($usettl) { * > // Store all the key values with current time. * @param string $key The key to delete. > $this->redis->zAdd($this->hash . self::TTL_SUFFIX, [], ...$ttlparams); * @return bool True if the delete operation succeeds, false otherwise. > // The return value to the zAdd function never indicates whether the operation succeeded */ > // (it returns zero when there was no error if the item is already in the list) so we public function delete($key) { > // ignore it.
< return ($this->redis->hDel($this->hash, $key) > 0);
> $ok = true; > if (!$this->redis->hDel($this->hash, $key)) { > $ok = false; > } > if ($this->definition->get_ttl()) { > // When TTL is enabled, also remove the key from the TTL list. > $this->redis->zRem($this->hash . self::TTL_SUFFIX, $key); > } > return $ok;
} /** * Delete many keys. * * @param array $keys The keys to delete. * @return int The number of keys successfully deleted. */ public function delete_many(array $keys) {
< // Redis needs the hash as the first argument, so we have to put it at the start of the array. < array_unshift($keys, $this->hash); < return call_user_func_array(array($this->redis, 'hDel'), $keys);
> // If there are no keys to delete, do nothing. > if (!$keys) { > return 0; > } > $count = $this->redis->hDel($this->hash, ...$keys); > if ($this->definition->get_ttl()) { > // When TTL is enabled, also remove the keys from the TTL list. > $this->redis->zRem($this->hash . self::TTL_SUFFIX, ...$keys); > } > return $count;
} /** * Purges all keys from the store. * * @return bool */ public function purge() {
> if ($this->definition->get_ttl()) { return ($this->redis->del($this->hash) !== false); > // Purge the TTL list as well. } > $this->redis->del($this->hash . self::TTL_SUFFIX); > // According to documentation, there is no error return for the 'del' command (it /** > // only returns the number of keys deleted, which could be 0 or 1 in this case) so we * Cleans up after an instance of the store. > // do not need to check the return value. */ > }
public function instance_deleted() {
< $this->purge();
$this->redis->close(); unset($this->redis); } /** * Determines if the store has a given key. * * @see cache_is_key_aware * @param string $key The key to check for. * @return bool True if the key exists, false if it does not. */ public function has($key) { return !empty($this->redis->hExists($this->hash, $key)); } /** * Determines if the store has any of the keys in a list. * * @see cache_is_key_aware * @param array $keys The keys to check for. * @return bool True if any of the keys are found, false none of the keys are found. */ public function has_any(array $keys) { foreach ($keys as $key) { if ($this->has($key)) { return true; } } return false; } /** * Determines if the store has all of the keys in a list. * * @see cache_is_key_aware * @param array $keys The keys to check for. * @return bool True if all of the keys are found, false otherwise. */ public function has_all(array $keys) { foreach ($keys as $key) { if (!$this->has($key)) { return false; } } return true; } /** * Tries to acquire a lock with a given name. * * @see cache_is_lockable * @param string $key Name of the lock to acquire. * @param string $ownerid Information to identify owner of lock if acquired. * @return bool True if the lock was acquired, false if it was not. */ public function acquire_lock($key, $ownerid) {
< return $this->redis->setnx($key, $ownerid);
> $timelimit = time() + $this->lockwait; > do { > // If the key doesn't already exist, grab it and return true. > if ($this->redis->setnx($key, $ownerid)) { > // Ensure Redis deletes the key after a bit in case something goes wrong. > $this->redis->expire($key, $this->locktimeout); > // If we haven't got it already, better register a shutdown function. > if ($this->currentlocks === null) { > core_shutdown_manager::register_function([$this, 'shutdown_release_locks']); > $this->currentlocks = []; > } > $this->currentlocks[$key] = $ownerid; > return true; > } > // Wait 1 second then retry. > sleep(1); > } while (time() < $timelimit); > return false; > } > > /** > * Releases any locks when the system shuts down, in case there is a crash or somebody forgets > * to use 'try-finally'. > * > * Do not call this function manually (except from unit test). > */ > public function shutdown_release_locks() { > foreach ($this->currentlocks as $key => $ownerid) { > debugging('Automatically releasing Redis cache lock: ' . $key . ' (' . $ownerid . > ') - did somebody forget to call release_lock()?', DEBUG_DEVELOPER); > $this->release_lock($key, $ownerid); > }
} /** * Checks a lock with a given name and owner information. * * @see cache_is_lockable * @param string $key Name of the lock to check. * @param string $ownerid Owner information to check existing lock against. * @return mixed True if the lock exists and the owner information matches, null if the lock does not * exist, and false otherwise. */ public function check_lock_state($key, $ownerid) { $result = $this->redis->get($key);
< if ($result === $ownerid) {
> if ($result === (string)$ownerid) {
return true; } if ($result === false) { return null; } return false; } /** * Finds all of the keys being used by this cache store instance. * * @return array of all keys in the hash as a numbered array. */ public function find_all() { return $this->redis->hKeys($this->hash); } /** * Finds all of the keys whose keys start with the given prefix. * * @param string $prefix * * @return array List of keys that match this prefix. */ public function find_by_prefix($prefix) { $return = []; foreach ($this->find_all() as $key) { if (strpos($key, $prefix) === 0) { $return[] = $key; } } return $return; } /** * Releases a given lock if the owner information matches. * * @see cache_is_lockable * @param string $key Name of the lock to release. * @param string $ownerid Owner information to use. * @return bool True if the lock is released, false if it is not. */ public function release_lock($key, $ownerid) { if ($this->check_lock_state($key, $ownerid)) {
> unset($this->currentlocks[$key]);
return ($this->redis->del($key) !== false); } return false; } /**
> * Runs TTL expiry process for this cache. * Creates a configuration array from given 'add instance' form data. > * * > * This is not part of the standard cache API and is intended for use by the scheduled task * @see cache_is_configurable > * \cachestore_redis\ttl. * @param stdClass $data > * * @return array > * @return array Various keys with information about how the expiry went */ > */ public static function config_get_configuration_array($data) { > public function expire_ttl(): array { return array( > $ttl = $this->definition->get_ttl(); 'server' => $data->server, > if (!$ttl) { 'prefix' => $data->prefix, > throw new \coding_exception('Cache definition ' . $this->definition->get_id() . ' does not use TTL'); 'password' => $data->password, > } 'serializer' => $data->serializer, > $limit = self::get_time() - $ttl; 'compressor' => $data->compressor, > $count = 0; ); > $batches = 0; } > $timebefore = microtime(true); > $memorybefore = $this->store_total_size(); /** > do { * Sets form data from a configuration array. > $keys = $this->redis->zRangeByScore($this->hash . self::TTL_SUFFIX, 0, $limit, * > ['limit' => [0, self::TTL_EXPIRE_BATCH]]); * @see cache_is_configurable > $this->delete_many($keys); * @param moodleform $editform > $count += count($keys); * @param array $config > $batches++; */ > } while (count($keys) === self::TTL_EXPIRE_BATCH); public static function config_set_edit_form_data(moodleform $editform, array $config) { > $memoryafter = $this->store_total_size(); $data = array(); > $timeafter = microtime(true); $data['server'] = $config['server']; > $data['prefix'] = !empty($config['prefix']) ? $config['prefix'] : ''; > $result = ['keys' => $count, 'batches' => $batches, 'time' => $timeafter - $timebefore]; $data['password'] = !empty($config['password']) ? $config['password'] : ''; > if ($memorybefore !== null) { if (!empty($config['serializer'])) { > $result['memory'] = $memorybefore - $memoryafter; $data['serializer'] = $config['serializer']; > } } > return $result; if (!empty($config['compressor'])) { > } $data['compressor'] = $config['compressor']; > } > /** $editform->set_data($data); > * Gets the current time for TTL functionality. This wrapper makes it easier to unit-test } > * the TTL behaviour. > * > * @return int Current time /** > */ * Creates an instance of the store for testing. > protected static function get_time(): int { * > global $CFG; * @param cache_definition $definition > if (PHPUNIT_TEST && !empty($CFG->phpunit_cachestore_redis_time)) { * @return mixed An instance of the store, or false if an instance cannot be created. > return $CFG->phpunit_cachestore_redis_time; */ > } public static function initialise_test_instance(cache_definition $definition) { > return time(); if (!self::are_requirements_met()) { > } return false; > } > /** $config = get_config('cachestore_redis'); > * Sets the current time (within unit test) for TTL functionality. if (empty($config->test_server)) { > * return false; > * This setting is stored in $CFG so will be automatically reset if you use resetAfterTest. } > * $configuration = array('server' => $config->test_server); > * @param int $time Current time (set 0 to start using real time). if (!empty($config->test_serializer)) { > */ $configuration['serializer'] = $config->test_serializer; > public static function set_phpunit_time(int $time = 0): void { } > global $CFG; if (!empty($config->test_password)) { > if (!PHPUNIT_TEST) { $configuration['password'] = $config->test_password; > throw new \coding_exception('Function only available during unit test'); } > } $cache = new cachestore_redis('Redis test', $configuration); > if ($time) { $cache->initialise($definition); > $CFG->phpunit_cachestore_redis_time = $time; > } else { return $cache; > unset($CFG->phpunit_cachestore_redis_time); } > } > } /** > * Return configuration to use when unit testing. > /** * > * Estimates the stored size, taking into account whether compression is turned on. * @return array > * */ > * @param mixed $key Key name public static function unit_test_configuration() { > * @param mixed $value Value global $DB; > * @return int Approximate stored size > */ if (!self::are_requirements_met() || !self::ready_to_be_used_for_testing()) { > public function estimate_stored_size($key, $value): int { throw new moodle_exception('TEST_CACHESTORE_REDIS_TESTSERVERS not configured, unable to create test configuration'); > if ($this->compressor == self::COMPRESSOR_NONE) { } > // If uncompressed, use default estimate. > return parent::estimate_stored_size($key, $value); return ['server' => TEST_CACHESTORE_REDIS_TESTSERVERS, > } else { 'prefix' => $DB->get_prefix(), > // If compressed, compress value. ]; > return strlen($this->serialize($key)) + strlen($this->compress($value)); } > } > } /** > * Returns true if this cache store instance is both suitable for testing, and ready for testing. > /** * > * Gets Redis reported memory usage. * When TEST_CACHESTORE_REDIS_TESTSERVERS is set, then we are ready to be use d for testing. > * * > * @return int|null Memory used by Redis or null if we don't know * @return bool > */ */ > public function store_total_size(): ?int { public static function ready_to_be_used_for_testing() { > try { return defined('TEST_CACHESTORE_REDIS_TESTSERVERS'); > $details = $this->redis->info('MEMORY'); } > } catch (\RedisException $e) { > return null; /** > } * Gets an array of options to use as the serialiser. > if (empty($details['used_memory'])) { * @return array > return null; */ > } else { public static function config_get_serializer_options() { > return (int)$details['used_memory']; $options = array( > } Redis::SERIALIZER_PHP => get_string('serializer_php', 'cachestore_redis') > } ); > > /**
if (defined('Redis::SERIALIZER_IGBINARY')) {
> } $options[Redis::SERIALIZER_IGBINARY] = get_string('serializer_igbinary', 'cachestore_redis'); > // Make it possible to test TTL performance by hacking a copy of the cache definition. } > if (!empty($config->test_ttl)) { return $options; > $definition = clone $definition; } > $property = (new ReflectionClass($definition))->getProperty('ttl'); > $property->setAccessible(true); /** > $property->setValue($definition, 999);
* Gets an array of options to use as the compressor. * * @return array */ public static function config_get_compressor_options() { $arr = [ self::COMPRESSOR_NONE => get_string('compressor_none', 'cachestore_redis'), self::COMPRESSOR_PHP_GZIP => get_string('compressor_php_gzip', 'cachestore_redis'), ]; // Check if the Zstandard PHP extension is installed. if (extension_loaded('zstd')) { $arr[self::COMPRESSOR_PHP_ZSTD] = get_string('compressor_php_zstd', 'cachestore_redis'); } return $arr; } /** * Compress the given value, serializing it first. * * @param mixed $value * @return string */ private function compress($value) { $value = $this->serialize($value); switch ($this->compressor) { case self::COMPRESSOR_NONE: return $value; case self::COMPRESSOR_PHP_GZIP: return gzencode($value); case self::COMPRESSOR_PHP_ZSTD: return zstd_compress($value); default: debugging("Invalid compressor: {$this->compressor}"); return $value; } } /** * Uncompresses (deflates) the data, unserialising it afterwards. * * @param string $value * @return mixed */ private function uncompress($value) { if ($value === false) { return false; } switch ($this->compressor) { case self::COMPRESSOR_NONE: break; case self::COMPRESSOR_PHP_GZIP: $value = gzdecode($value); break; case self::COMPRESSOR_PHP_ZSTD: $value = zstd_uncompress($value); break; default: debugging("Invalid compressor: {$this->compressor}"); } return $this->unserialize($value); } /** * Serializes the data according to the configured serializer. * * @param mixed $value * @return string */ private function serialize($value) { switch ($this->serializer) { case Redis::SERIALIZER_NONE: return $value; case Redis::SERIALIZER_PHP: return serialize($value); case defined('Redis::SERIALIZER_IGBINARY') && Redis::SERIALIZER_IGBINARY: return igbinary_serialize($value); default: debugging("Invalid serializer: {$this->serializer}"); return $value; } } /** * Unserializes the data according to the configured serializer * * @param string $value * @return mixed */ private function unserialize($value) { switch ($this->serializer) { case Redis::SERIALIZER_NONE: return $value; case Redis::SERIALIZER_PHP: return unserialize($value); case defined('Redis::SERIALIZER_IGBINARY') && Redis::SERIALIZER_IGBINARY: return igbinary_unserialize($value); default: debugging("Invalid serializer: {$this->serializer}"); return $value; } } }