syncguard/redis/operations/is-locked.js

Functional TypeScript library for distributed locking across microservices. Prevents race conditions with Redis, PostgreSQL, Firestore, and custom backends. Features automatic lock management, timeout handling, and extensible architecture.

// SPDX-FileCopyrightText: 2025-present Kriasoft
// SPDX-License-Identifier: MIT
import { LockError, makeStorageKey, normalizeAndValidateKey, } from "../../common/backend.js";
import { TIME_TOLERANCE_MS } from "../../common/time-predicates.js";
import { checkAborted, mapRedisError } from "../errors.js";
import { IS_LOCKED_SCRIPT } from "../scripts.js";
/**
 * Creates isLocked operation using Lua script for atomicity.
 * Script checks expiration and optionally cleans up with safety guard.
 * @see ../scripts.ts for IS_LOCKED_SCRIPT implementation
 */
export function createIsLockedOperation(redis, config) {
    return async (opts) => {
        try {
            // Pre-dispatch abort check (ioredis does not accept AbortSignal)
            checkAborted(opts.signal);
            const normalizedKey = normalizeAndValidateKey(opts.key);
            const REDIS_LIMIT_BYTES = 1000;
            const RESERVE_BYTES = 26; // ":id:" (4 bytes) + 22-char lockId
            const lockKey = makeStorageKey(config.keyPrefix, normalizedKey, REDIS_LIMIT_BYTES, RESERVE_BYTES);
            // Prefer cached command (ioredis) over eval for better performance
            const scriptResult = redis.checkLock
                ? await redis.checkLock(lockKey, config.keyPrefix, TIME_TOLERANCE_MS.toString(), config.cleanupInIsLocked.toString())
                : (await redis.eval(IS_LOCKED_SCRIPT, 1, lockKey, config.keyPrefix, TIME_TOLERANCE_MS.toString(), config.cleanupInIsLocked.toString()));
            return scriptResult === 1;
        }
        catch (error) {
            if (error instanceof LockError) {
                throw error;
            }
            throw mapRedisError(error);
        }
    };
}