@zenweb/cache/dist/locker.js

Zenweb Cache module

import { randomBytes, createHash } from 'node:crypto';
import { runRedisScript } from './utils.js';
const RELEASE_SCRIPT = `
if redis.call("get", KEYS[1]) == ARGV[1] then
    return redis.call("del", KEYS[1])
else
    return 0
end
`;
const RELEASE_SCRIPT_HASH = createHash('sha1').update(RELEASE_SCRIPT).digest('hex');
/**
 * 基于 Redis 的分布式锁
 */
export class Locker {
    redis;
    key;
    timeout;
    value = randomBytes(16).toString('hex');
    /**
     * @param redis Redis 实例
     * @param key 锁KEY
     * @param timeout 锁超时(毫秒) 默认 10秒
     */
    constructor(redis, key, timeout = 10000) {
        this.redis = redis;
        this.key = key;
        this.timeout = timeout;
    }
    /**
     * 取得锁
     * @returns true 取得成功, 否则失败
     */
    async acquire() {
        // NX 不存在key 才创建
        // PX 过期时间
        const result = await this.redis.call('SET', this.key, this.value, 'NX', 'PX', this.timeout);
        return result === 'OK';
    }
    /**
     * 释放锁
     */
    async release() {
        return (await runRedisScript(this.redis, RELEASE_SCRIPT_HASH, RELEASE_SCRIPT, [this.key], [this.value])) === 1;
    }
    /**
     * 使用锁回调
     * @param callback 获取结果回调 true: 成功 false: 失败
     */
    async using(callback) {
        if (await this.acquire()) {
            try {
                await callback(true);
                return;
            }
            finally {
                await this.release();
            }
        }
        callback(false);
    }
}