Method tryLock

packages/cache/src/service.ts:214–243

* Try to acquire a distributed lock (atomic SET NX operation) * @param key - Lock key * @param value - Lock value (typically "locked" or instance identifier) * @param ttlMs - Time to live in milliseconds (lock expiration) * @returns Result containing boolean indicating if lock was acquir

(key: CacheKey, value: string, ttlMs: number)

   * @returns Result containing boolean indicating if lock was acquired, or an error
   */
  async tryLock(key: CacheKey, value: string, ttlMs: number): Promise<Result<boolean, CacheError>> {
    // Check Redis availability first
    if (!this.isRedisClientReady()) {
      return err({
        code: ErrorCode.RedisConnectionError,
      });
    }

    const validation = validateInputs([key, ZCacheKey], [ttlMs, ZTtlMs]);
    if (!validation.ok) {
      return validation;
    }

    try {
      // Use SET with NX (only set if not exists) and PX (expiration in milliseconds) for atomic lock acquisition
      const result = await this.withTimeout(
        this.redis.set(key, value, {
          NX: true,
          PX: ttlMs,
        })
      );
      // SET returns "OK" if lock was acquired, null if key already exists
      return ok(result === "OK");
    } catch (error) {
      logger.error({ error, key, ttlMs }, "Cache lock operation failed");
      return err({
        code: ErrorCode.RedisOperationError,
      });
    }
  }

  /**
   * Cache wrapper for functions (cache-aside).