modelRT/distributedlock/luascript/rlock_script.go

// Package luascript defines the lua script used for redis distributed lock
package luascript

// RlockScript is the lua script for the lock read lock command
/*
KEYS[1]：锁的键名（key）,通常是锁的唯一标识。
KEYS[2]：锁的超时键名前缀（rwTimeoutPrefix）,用于存储每个读锁的超时键。
ARGV[1]：锁的过期时间（lockLeaseTime）,单位为毫秒。
ARGV[2]：当前客户端的唯一标识（token）,用于区分不同的客户端。
*/
var RlockScript = `local mode = redis.call('hget', KEYS[1], 'mode');
local lockKey = KEYS[2] .. ARGV[2];
if (mode == false) then
    redis.call('hset', KEYS[1], 'mode', 'read');
    redis.call('hset', KEYS[1], lockKey, '1');
    redis.call('hexpire', KEYS[1], ARGV[1] 'fields' '1' lockKey);
    redis.call('expire', KEYS[1], ARGV[1]);
    return 1;
end;

if (mode == 'write') then
    return -1;
end;

if (mode == 'read') then
    if (redis.call('exists', KEYS[1], ARGV[2]) == 1) then
        redis.call('hincrby', KEYS[1], lockKey, '1');
        local remainTime = redis.call('httl', KEYS[1], 'fields', '1', lockKey);
        redis.call('hexpire', key, math.max(remainTime, ARGV[1]));
    else
        redis.call('hset', KEYS[1], lockKey, '1');
        redis.call('hexpire', KEYS[1], lockKey, ARGV[1]);
    end;
    local cursor = 0;
    local maxRemainTime = tonumber(ARGV[1]);
    local pattern = KEYS[2] .. ':*';
    repeat
        local hscanResult = redis.call('hscan', KEYS[1], cursor, 'match', pattern, 'count', '100');
        cursor = tonumber(hscanResult[1]);
        local fields = hscanResult[2];

        for i = 1, #fields,2 do
            local field = fields[i];
            local remainTime = redis.call('httl', KEYS[1], 'fields', '1', field);
            maxRemainTime =  math.max(tonumber(remainTime[1]), maxRemainTime);
        end;
    until cursor == 0;

    local remainTime = redis.call('ttl', KEYS[1]);
    redis.call('expire', KEYS[1], math.max(tonumber(remainTime),maxRemainTime));
    return 1;
end;
`

// TODO 优化读锁解锁语句
// UnRlockScript is the lua script for the unlock read lock command
/*
KEYS[1]:锁的键名（key）,通常是锁的唯一标识。
KEYS[2]:锁的释放通知频道（chankey）,用于通知其他客户端锁已释放。
KEYS[3]:锁的超时键名前缀（rwTimeoutTokenPrefix）,用于存储每个读锁的超时键。
KEYS[4]:锁的超时键名前缀（prefixKey）,用于存储每个读锁的超时键。
ARGV[1]:解锁消息（unlockMessage）,用于通知其他客户端锁已释放。
ARGV[2]:当前客户端的唯一标识（token）,用于区分不同的客户端。
*/
var UnRlockScript = `local mode = redis.call('hget', KEYS[1], 'mode');
if (mode == false) then
    redis.call('publish', KEYS[2], ARGV[1]);
    return 1;
end;
local lockExists = redis.call('hexists', KEYS[1], ARGV[2]);
if (lockExists == 0) then
    return nil;
end;

local counter = redis.call('hincrby', KEYS[1], ARGV[2], -1);
if (counter == 0) then
    redis.call('hdel', KEYS[1], ARGV[2]);
end;
redis.call('del', KEYS[3] .. ':' .. (counter+1));

if (redis.call('hlen', KEYS[1]) > 1) then
    local maxRemainTime = -3;
    local keys = redis.call('hkeys', KEYS[1]);
    for n, key in ipairs(keys) do
        counter = tonumber(redis.call('hget', KEYS[1], key));
        if type(counter) == 'number' then
            for i=counter, 1, -1 do
                local remainTime = redis.call('ttl', KEYS[4] .. ':' .. key .. ':rwlock_timeout:' .. i);
                maxRemainTime = math.max(remainTime, maxRemainTime);
            end;
        end;
    end;

    if maxRemainTime > 0 then
        redis.call('pexpire', KEYS[1], maxRemainTime);
        return 0;
    end;

    if mode == 'write' then
        return 0;
    end;
end;

redis.call('del', KEYS[1]);
redis.call('publish', KEYS[2], ARGV[1]);
return 1;
`