RemiSan\Lock\LockStore\RedisLockStore

Complexity

Total Complexity

9

Size/Duplication

Total Lines	79
Duplicated Lines	0 %

Coupling/Cohesion

Components	1
Dependencies	1

Test Coverage

Coverage

100%

Importance

Changes	2
Bugs	0	Features	1

5 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	0	7	2
A	set()	0	10	3
A	exists()	0	4	1
A	delete()	0	16	1
A	getDrift()	0	10	2

<?php

namespace RemiSan\Lock\LockStore;

use RemiSan\Lock\Lock;
use RemiSan\Lock\LockStore;

class RedisLockStore implements LockStore
{
    /** @var float */
    const CLOCK_DRIFT_FACTOR = 0.01;

    /** @var int */
    const REDIS_EXPIRES_PRECISION = 2;

    /** @var \Redis */
    private $redis;

    /**
     * RedisLockStore constructor.
     *
     * @param \Redis $redis
     */
    public function __construct(\Redis $redis)
    {
        if (!$redis->isConnected()) {
            throw new \InvalidArgumentException('The Redis instance must be connected.');
        }
        $this->redis = $redis;
    }
    /**
     * {@inheritdoc}
     */
    public function set(Lock $lock, $ttl = null)
    {
        $options = ['NX'];

        if ($ttl !== null && $ttl > 0) {
            $options['PX'] = (int) $ttl;
        }

        return (bool) $this->redis->set($lock->getResource(), (string) $lock->getToken(), $options);
    }

    /**
     * {@inheritdoc}
     */
    public function exists($resource)
    {
        return (bool) $this->redis->get($resource);
    }

    /**
     * {@inheritdoc}
     */
    public function delete(Lock $lock)
    {
        $script = '
            if redis.call("GET", KEYS[1]) == ARGV[1] then
                return redis.call("DEL", KEYS[1])
            else
                return 0
            end
        ';

        return (bool) $this->redis->evaluate(
            $script,
            [$lock->getResource(), (string) $lock->getToken()],
            1
        );
    }

    /**
     * {@inheritdoc}
     */
    public function getDrift($ttl)
    {
        // Add 2 milliseconds to the drift to account for Redis expires
        // precision, which is 1 millisecond, plus 1 millisecond min drift
        // for small TTLs.

        $minDrift = ($ttl) ? (int) ceil($ttl * self::CLOCK_DRIFT_FACTOR) : 0;

        return $minDrift + self::REDIS_EXPIRES_PRECISION;
    }
}