redlock-js

RedLock-JS

RedLock is a TypeScript library for acquiring and releasing locks using Redis, designed for use in Node.js applications.

Installation

Install the RedLock library using npm:

npm install redlock-js

Usage

To use RedLock in your Node.js application, follow these steps:

1. Import the RedLock class:

import RedLock, { LockOptions } from 'redlock-js';

1. Create an instance of RedLock with the required configuration:

const lockOptions: LockOptions = {
  redis: {
    host: 'localhost',
    port: 6379,
  },
  key: 'my-lock',
  interval: 100, // Optional, specify the retry interval in milliseconds
};

const redlock = new RedLock(lockOptions);

1. Acquire and release locks as needed:

// Acquire a lock
await redlock.lock();

// Perform your critical section of code here

// Release the lock when done
await redlock.release();

Configuration Options

You can configure RedLock by providing options when creating an instance:

• redis: Redis connection options.
• cluster: If you're using a Redis cluster, provide cluster configuration.
• key: The unique key for your lock.
• interval (default: 100): Retry interval in milliseconds when attempting to acquire the lock.
• expire (default: 300): Expiration time in seconds for the lock key. Setting an expiration time allows you to automatically release the lock after a certain duration, effectively locking a resource without needing an explicit release operation.

Additional Functionality

Automatic Cleanup

RedLock includes an automatic cleanup function that can be used to clean up leftover lock keys. You can use the clean method to scan and delete expired lock keys from the Redis database.

await redlock.clean();

By calling the clean method, you can ensure that expired lock keys are removed, preventing potential issues with stale locks.

Checking Lock Status

You can also check whether a lock is currently active using the isLocking method:

const lockingStatus = await redlock.isLocking();
console.log(`Is locking: ${lockingStatus}`);

The isLocking method returns a boolean indicating whether the lock is currently active or not.

Close the Redis Connection

To properly release resources and end the Redis connection, use the end method:

await redlock.end();

Calling the end method will gracefully close the connection to the Redis server. Additionally, when you call the release method, the lock will be released and the associated Redis connection will be closed.