node-file-lock

WHAT IS THIS ##

Just a file system based lock, to avoid multi process Node application(such as pm2) make problems while operating the file system.

USAGE ##

``js
const Locker = require('node-file-lock');

(async() => {
// only the first Locker(file) will success, others with the same file param call will throw error
const lock = new Locker('custom-your-specified-file-name');

// do the async download and fs operating stuff here use await
// codes between lock and unlock will not be executed in parallel between multiple processes
// only the first process will execute this part of the code, others will throw an error at the previous line of code

// unlock the locker, then other process can do the same thing now
lock.unlock();
})();
`

`js
// support the second param, duration in milliseconds, which will make the lock auto-release after the duration exceed
const lock = new Locker('custom-your-specified-file-name', 3000);
const unlock = lock.unlock.bind(lock);

// do the async download and fs operating stuff here

new Promise((res, rej) => {
// codes here
})
.then(unlock, unlock);
``