Class yii\redis\Mutex

All Classes | Properties | Methods

Inheritance	yii\redis\Mutex » yii\mutex\Mutex
Uses Traits	yii\mutex\RetryAcquireTrait
Available since extension's version	2.0.6
Source Code	https://github.com/yiisoft/yii2-redis/blob/master/src/Mutex.php

Redis Mutex implements a mutex component using redis as the storage medium.

Redis Mutex requires redis version 2.6.12 or higher to work properly.

It needs to be configured with a redis yii\redis\Connection that is also configured as an application component. By default it will use the redis application component.

To use redis Mutex as the application component, configure the application as follows:

[
    'components' => [
        'mutex' => [
            'class' => 'yii\redis\Mutex',
            'redis' => [
                'hostname' => 'localhost',
                'port' => 6379,
                'database' => 0,
            ]
        ],
    ],
]

Or if you have configured the redis yii\redis\Connection as an application component, the following is sufficient:

[
    'components' => [
        'mutex' => [
            'class' => 'yii\redis\Mutex',
            // 'redis' => 'redis' // id of the connection application component
        ],
    ],
]

Public Properties

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Property	Type	Description	Defined By
$expire	integer	The number of seconds in which the lock will be auto released.	yii\redis\Mutex
$keyPrefix	string	A string prefixed to every cache key so that it is unique.	yii\redis\Mutex
$redis	yii\redis\Connection\|string\|array	The Redis yii\redis\Connection object or the application component ID of the Redis yii\redis\Connection.	yii\redis\Mutex

Public Methods

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Method	Description	Defined By
init()	Initializes the redis Mutex component.	yii\redis\Mutex

Protected Methods

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Method	Description	Defined By
acquireLock()	Acquires a lock by name.	yii\redis\Mutex
calculateKey()	Generates a unique key used for storing the mutex in Redis.	yii\redis\Mutex
releaseLock()	Releases acquired lock. This method will return `false` in case the lock was not found or Redis command failed.	yii\redis\Mutex

Property Details

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$expire public property

The number of seconds in which the lock will be auto released.

public integer $expire = 30

$keyPrefix public property

A string prefixed to every cache key so that it is unique. If not set, it will use a prefix generated from Application::id. You may set this property to be an empty string if you don't want to use key prefix. It is recommended that you explicitly set this property to some static value if the cached data needs to be shared among multiple applications.

public string $keyPrefix = null

$redis public property

The Redis yii\redis\Connection object or the application component ID of the Redis yii\redis\Connection. This can also be an array that is used to create a redis yii\redis\Connection instance in case you do not want do configure redis connection as an application component. After the Mutex object is created, if you want to change this property, you should only assign it with a Redis yii\redis\Connection object.

public yii\redis\Connection|string|array $redis = 'redis'

Method Details

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acquireLock() protected method

Acquires a lock by name.

protected boolean acquireLock ( string $name, integer $timeout = 0 )
$name	string	Of the lock to be acquired. Must be unique.
$timeout	integer	Time (in seconds) to wait for lock to be released. Defaults to `0` meaning that method will return false immediately in case lock was already acquired.
return	boolean	Lock acquiring result.

Source code

                protected function acquireLock($name, $timeout = 0)
{
    $key = $this->calculateKey($name);
    $value = Yii::$app->security->generateRandomString(20);
    $result = $this->retryAcquire($timeout, function () use ($key, $value) {
        return $this->redis->executeCommand('SET', [$key, $value, 'NX', 'PX', (int) ($this->expire * 1000)]);
    });
    if ($result) {
        $this->_lockValues[$name] = $value;
    }
    return $result;
}

calculateKey() protected method

Generates a unique key used for storing the mutex in Redis.

protected string calculateKey ( string $name )
$name	string	Mutex name.
return	string	A safe cache key associated with the mutex name.

Source code

                protected function calculateKey($name)
{
    return $this->keyPrefix . md5(json_encode([__CLASS__, $name]));
}

init() public method

Initializes the redis Mutex component.

This method will initialize the $redis property to make sure it refers to a valid redis connection.

public mixed init ( )
throws	\yii\base\InvalidConfigException	if $redis is invalid.

Source code

                public function init()
{
    parent::init();
    $this->redis = Instance::ensure($this->redis, Connection::className());
    if ($this->keyPrefix === null) {
        $this->keyPrefix = substr(md5(Yii::$app->id), 0, 5);
    }
}

releaseLock() protected method

Releases acquired lock. This method will return false in case the lock was not found or Redis command failed.

protected boolean releaseLock ( string $name )
$name	string	Of the lock to be released. This lock must already exist.
return	boolean	Lock release result: `false` in case named lock was not found or Redis command failed.

Source code

                protected function releaseLock($name)
{
    static $releaseLuaScript = <<<LUA
edis.call("GET",KEYS[1])==ARGV[1] then
return redis.call("DEL",KEYS[1])

return 0

    if (
        !isset($this->_lockValues[$name])
        || !$this->redis->executeCommand('EVAL', [
            $releaseLuaScript,
            1,
            $this->calculateKey($name),
            $this->_lockValues[$name],
        ])
    ) {
        return false;
    }
    unset($this->_lockValues[$name]);
    return true;
}