/// <summary>
/// Tries to lock the given key.
/// </summary>
/// <param name="key">The key to lock.</param>
/// <param name="luaScript">The lua script to lock the key.</param>
/// <param name="extraKeys">The extra keys that will be provided to the <paramref name="luaScript"/></param>
/// <param name="extraValues">The extra values that will be provided to the <paramref name="luaScript"/></param>
/// <returns>The lock value used to lock the key.</returns>
/// <exception cref="CacheException">Thrown if the lock was not acquired.</exception>
public string Lock(string key, string luaScript, RedisKey[] extraKeys, RedisValue[] extraValues)
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
var lockKey = $"{key}{_lockKeySuffix}";
string Context() => lockKey;
return(_retryPolicy.Execute(() =>
{
var lockValue = _lockValueProvider.GetValue();
if (!string.IsNullOrEmpty(luaScript))
{
var keys = new RedisKey[] { lockKey };
if (extraKeys != null)
{
keys = keys.Concat(extraKeys).ToArray();
}
var values = new RedisValue[] { lockValue, (long)_lockTimeout.TotalMilliseconds };
if (extraValues != null)
{
values = values.Concat(extraValues).ToArray();
}
var result = (RedisValue[])_database.ScriptEvaluate(luaScript, keys, values);
if ((bool)result[0])
{
return lockValue;
}
}
else if (_database.LockTake(lockKey, lockValue, _lockTimeout))
{
return lockValue;
}
return null; // retry
}, Context));
}
