node-etcd-lock

Distributed locks powered by etcd v3 for Node.js.

Installation

npm install node-etcd-lock

Usage

'use strict'
const assert = require('assert')
const Locker = require('node-etcd-lock')

const locker = new Locker({ address: '127.0.0.1:2379' })

;(async function () {
  // Acquire a lock for a specified recource.
  const lock = await locker.lock('resource_key', 3 * 1000)
  // This lock will be acquired after 3000 ms.
  const anotherLock = await locker.lock('resource_key', 3 * 1000)
  // Unlock the lock manually.
  await anotherLock.unlock()

  assert((await locker.isLocked('resource_key')) === false)
})(console.error)

API

Class Locker

new Locker({ address, defaultTimeout, rootCerts, privateKey, certChain })

• address String: The address of etcd(v3) server, by default is '127.0.0.1:2379'
• defaultTimeout Number: Milliseconds of lock's default timeout, by default is 5000.
• etcdKeyPrefix String: Prefix of the keys of locks in etcd, by default is '__etcd_lock/'.
• rootCerts, privateKey, certChain Buffer: Options to create a GRPC SSL Credentials object, see https://grpc.io/grpc/node/src_credentials.js.html#line85.

lock({ keyName, timeout = this.defaultTimeout })

• keyName String: The key of the resource to lock.
• timeout Number: Milliseconds of the lock's timeout.

Lock the resource with keyName, return a Promise which will be resolved with a Lock instance when the resource is available.

isLocked(keyName)

• keyName String: The key of the resource which need to be checked.

Check whether the resource with keyName has already been locked.

Class Lock

unlock()

Unlock this lock immediately.