Summary

Add centralised lock support in NodeJS. Underneath, its a simple lock system using TCP communication. Also on Promise. Good luck!

This made to tackles:

• I can't f$%W! (frankly) use Redis
• Race condition in concurrent running async tasks
• Wild access to a resource from multiple node processes
• Yeah those kind of things

Installation

Install gudlock using the npm package manager:

$ npm install gudlock

User Guide

After deciding up how lock-server is run, using locks is as simple as these:

import { client as gudlock } from 'gudlock'

// A. Prerequisites
// Do this if you set your server in custom host:port
gudlock.attach({ port: 8827, host: '127.0.0.1' })

// B. Using Locks and Releasing
// acquiring lock will return function to release lock
// releasing lock is done by calling returned function

const release = await gudlock.lock()
console.log('important processing is running...')
await release()

Its also possible to give the locks name, so its possible to have >1 lock active in the same time, example:

// specify lock name/identifier on acquire. 
// to release the lock, no need to specify lock's name

const release = await gudlock.lock('LOCK_NAME_HERE')

console.log('important processing is running...')

await release()

Setting up Lock-Server

This will add package called gudlock in your project. There are two options on using this package depending on where you want to run the locks-server:

1. Run server inside a node app
2. Run server as separate node app

1. Running server in node app

This method will attach server to process & runtime of another node app (parent app).

PROS: Generally lighter resources consumption. CONS: Lock service will dies when parent node go down.

How to use this method:

// basically include and start listening in node-app's entry point

import { server } from 'gudlock'

server.start({ port: 8827, host: '127.0.0.1' })

console.log(`Lock server running on 127.0.0.1:8827`)

2. Running server as separate node process

This method will start server as individual process & runtime.

PROS: Lock service wont depend on any other node app's state. CONS: Generally bigger resources consumption.

How to use this method:

# run this command 
$ node node_modules/gudlock/bin/server

# to specify custom host:port 
$ node node_modules/gudlock/bin/server --port=7676 --host=128.23.12.3

# this will start a new node process
# default port is 6969 and ip 127.0.0.1

Contributing

Documentation is an OPEN Open Source Project. This means that:

Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit.